

June 2020

Prepared for:

Department of Veterans Affairs

Veterans Health Administration

Health Services Research & Development Service

Washington, DC 20420 

Prepared by:

Evidence Synthesis Program (ESP) Center

West Los Angeles VA Medical Center

Los Angeles, CA 

Paul G. Shekelle, MD, PhD, Director 

Robot-assisted Procedures in 

General Surgery: 

Cholecystectomy, Inguinal and 

Ventral Hernia Repairs

Authors: 

Principal Investigators: 

Melinda Maggard-Gibbons, MD 

Paul G. Shekelle, MD, PhD 

Co-Investigators: 

Mark Girgis, MD

Linda Ye, MD 

Rivfka Shenoy, MD 

Michael Mederos, MD

Christopher P. Childers, MD, PhD

Amber Tang, BA 

Research Associates: 

Selene Mak, PhD, MPH

Meron Begashaw, MPH

Marika S. Booth, MS 

Evidence Synthesis Program

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Robot-assisted Procedures in General Surgery Evidence Synthesis Program

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PREFACE 

The VA Evidence Synthesis Program (ESP) was established in 2007 to provide timely and accurate 

syntheses of targeted healthcare topics of importance to clinicians, managers, and policymakers as they 

work to improve the health and healthcare of Veterans. These reports help: 

• Develop clinical policies informed by evidence; 

• Implement effective services to improve patient outcomes and to support VA clinical practice 

guidelines and performance measures; and 

• Set the direction for future research to address gaps in clinical knowledge. 

The program is comprised of 4 ESP Centers across the US and a Coordinating Center located in 

Portland, Oregon. Center Directors are VA clinicians and recognized leaders in the field of evidence 

synthesis with close ties to the AHRQ Evidence-based Practice Center Program and Cochrane 

Collaboration. The Coordinating Center was created to manage program operations, ensure 

methodological consistency and quality of products, and interface with stakeholders. To ensure 

responsiveness to the needs of decision-makers, the program is governed by a Steering Committee 

comprised of health system leadership and researchers. The program solicits nominations for review 

topics several times a year via the program website. 

Comments on this evidence report are welcome and can be sent to Nicole Floyd, Deputy Director, ESP

Coordinating Center at Nicole.Floyd@va.gov. 

Recommended citation: Maggard-Gibbons M, Girgis M, Ye L, Shenoy R, Mederos M, Childers CP, 

Tang A, Mak SS, Begashaw M, Booth MS, Shekelle PG, Robot-Assisted Procedures in General 

Surgery: Cholecystectomy, Inguinal and Ventral Hernia Repairs. Los Angeles: Evidence Synthesis 

Program, Health Services Research and Development Service, Office of Research and Development, 

Department of Veterans Affairs. VA ESP Project #05-226; 2020. Available at: 

https://www.hsrd.research.va.gov/publications/esp/reports.cfm. 

This report is based on research conducted by the Evidence Synthesis Program (ESP) Center located at the West 

Los Angeles VA Medical Center, Los Angeles, CA, funded by the Department of Veterans Affairs, Veterans 

Health Administration, Health Services Research and Development. The findings and conclusions in this document 

are those of the author(s) who are responsible for its contents; the findings and conclusions do not necessarily 

represent the views of the Department of Veterans Affairs or the United States government. Therefore, no statement 

in this article should be construed as an official position of the Department of Veterans Affairs. No investigators 

have any affiliations or financial involvement (eg, employment, consultancies, honoraria, stock ownership or 

options, expert testimony, grants or patents received or pending, or royalties) that conflict with material presented 

in the report.
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ACKNOWLEDGMENTS 

This topic was developed in response to a nomination by Dr. Mark Wilson, National Director of 

Surgery, and Dr. William Gunnar, Executive Director, National Center for Patient Safety and 

former National Director of Surgery. The scope was further developed with input from the topic 

nominators (ie, Operational Partners), the ESP Coordinating Center, the review team, and the 

technical expert panel (TEP).

In designing the study questions and methodology at the outset of this report, the ESP consulted 

several technical and content experts. Broad expertise and perspectives were sought. Divergent 

and conflicting opinions are common and perceived as healthy scientific discourse that results in 

a thoughtful, relevant systematic review. Therefore, in the end, study questions, design, 

methodologic approaches, and/or conclusions do not necessarily represent the views of 

individual technical and content experts. 

The authors gratefully acknowledge Roberta Shanman, Jon Bergman, and the following 

individuals for their contributions to this project: 

Operational Partners

Operational partners are system-level stakeholders who have requested the report to inform 

decision-making. They recommend Technical Expert Panel (TEP) participants; assure VA 

relevance; help develop and approve final project scope and timeframe for completion; provide 

feedback on draft report; and provide consultation on strategies for dissemination of the report to 

field and relevant groups. 

Mark Wilson, MD, PhD 

National Director of Surgery 

Department of Veterans Affairs

William Gunnar, MD

Executive Director, National Center for Patient Safety

Former National Director of Surgery 

Department of Veterans Affairs

Technical Expert Panel (TEP)

To ensure robust, scientifically relevant work, the TEP guides topic refinement; provides input 

on key questions and eligibility criteria, advising on substantive issues or possibly overlooked 

areas of research; assures VA relevance; and provides feedback on work in progress. TEP 

members are listed below: 

Bryanna Emr, MD 

General Surgeon, Clinical Assistant Professor, University of Pittsburgh and VA Pittsburgh 

Healthcare System

Timothy Frankel, MD 

Assistant Professor, General Surgery and Surgical Oncology, University of Michigan HospitalsMichigan Medicine and Veterans Affairs Ann Arbor Healthcare System 
Robot-assisted Procedures in General Surgery Evidence Synthesis Program

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Tomas Heimann, MD

Professor of Surgery, Colorectal Surgeon, Mount Sinai Hospital, New York, Chief of Surgery at 

James J. Peters VA Medical Center in New York, an affiliate of the Mount Sinai School of 

Medicine. 

Frederick Luchette, MD

Chief of Surgical Service Line, Edward Hines Jr., VA Hospital; Professor of Surgery, 

Department of Surgery Stritch School of Medicine, Loyola University of Chicago 

Peer Reviewers

The Coordinating Center sought input from external peer reviewers to review the draft report and 

provide feedback on the objectives, scope, methods used, perception of bias, and omitted 

evidence. Peer reviewers must disclose any relevant financial or non-financial conflicts of 

interest. Because of their unique clinical or content expertise, individuals with potential conflicts 

may be retained. The Coordinating Center and the ESP Center work to balance, manage, or 

mitigate any potential nonfinancial conflicts of interest identified. 
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TABLE OF CONTENTS 

ACKNOWLEDGMENTS ........................................................................................................... II

EXECUTIVE SUMMARY .......................................................................................................... 8

Introduction .................................................................................................................................. 8

Methods........................................................................................................................................ 8

Data Sources and Searches .......................................................................................................... 9

Study Selection ............................................................................................................................ 9

Data Abstraction and Quality Assessment ................................................................................... 9

Data Synthesis and Analysis ........................................................................................................ 9

Results ........................................................................................................................................ 10

Results of Literature Search ....................................................................................................... 10

Summary of Results for Key Questions ..................................................................................... 11

Discussion .................................................................................................................................. 13

Key Findings and Strength of Evidence .................................................................................... 13

Applicability .............................................................................................................................. 13

Research Gaps/Future Research ................................................................................................ 14

Conclusions ................................................................................................................................ 16

Abbreviations Table ................................................................................................................... 17

EVIDENCE REPORT ................................................................................................................ 18

INTRODUCTION....................................................................................................................... 18

METHODS .................................................................................................................................. 19

Topic Development .................................................................................................................... 19

Search Strategy .......................................................................................................................... 19

Study Selection .......................................................................................................................... 20

Data Abstraction ........................................................................................................................ 20

Quality Assessment .................................................................................................................... 20

Data Synthesis ............................................................................................................................ 21

Rating the Body of Evidence ..................................................................................................... 22

Peer Review ............................................................................................................................... 23

RESULTS .................................................................................................................................... 24

The Risk of Bias of Studies ....................................................................................................... 25

Key Question 1A – Cholecystectomy: What is the clinical effectiveness of robot-assisted 

surgery compared to conventional laparoscopic surgery for cholecystectomy? ....................... 29

Certainty of Evidence for Key Question 1A .............................................................................. 35
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Key Question 2A – Cholecystectomy: What is the cost-effectiveness of robot-assisted 

surgery compared to conventional laparoscopic surgery for cholecystectomy? ....................... 37

Summary of Findings ................................................................................................................. 46

Certainty of Evidence for Key Question 2A .............................................................................. 46

Key Question 1B – Inguinal Hernia Surgery: What is the clinical effectiveness of robotassisted surgery compared to conventional laparoscopic or open surgery for inguinal hernia 

repair? ........................................................................................................................................ 46

Summary of Findings ................................................................................................................. 55

Certainty of Evidence for Key Question 1B .............................................................................. 55

Key Question 2B – Inguinal Hernia Surgery: What is the cost-effectiveness of robotassisted surgery compared to conventional laparoscopic or open surgery for inguinal 

hernia repair? ............................................................................................................................. 56

Summary of Findings ................................................................................................................. 58

Certainty of Evidence for Key Question 2B .............................................................................. 59

Key Question 1C – Ventral Hernia Surgery: What is the clinical effectiveness of 

robot-assisted surgery compared to conventional laparoscopic or open surgery for 

ventral hernia repair? ................................................................................................................. 59

Summary of Findings ................................................................................................................. 68

Certainty of Evidence for Key Question 1C .............................................................................. 68

Key Question 2C – Ventral Hernia Surgery: what is the cost-effectiveness of robotassisted surgery compared to conventional laparoscopic or open surgery for ventral 

hernia repair? ............................................................................................................................. 70

Summary of Findings ................................................................................................................. 72

Certainty of Evidence for Key Question 2C .............................................................................. 72

SUMMARY AND DISCUSSION .............................................................................................. 73

Summary of Evidence by Key Question .................................................................................... 73

Limitations ................................................................................................................................. 74

Publication Bias ......................................................................................................................... 74

Study Quality ............................................................................................................................. 75

Heterogeneity ............................................................................................................................. 75

Applicability of Findings to the VA Population ........................................................................ 75

Research Gaps/Future Research ................................................................................................ 75

Conclusions ................................................................................................................................ 78

REFERENCES ............................................................................................................................ 79

TABLES

Table 1. Certainty of Evidence for Cholecystectomy Studies ................................................... 36

Table 2. Evidence Table for Cholecystectomy Cost Studies ..................................................... 38
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Table 3. Certainty of Evidence for Inguinal Hernia Repair Studies .......................................... 55

Table 4. Evidence Table for Inguinal Hernia Cost Studies ....................................................... 57

Table 5. Certainty of Evidence for Ventral Hernia Repair Studies ........................................... 69

Table 6. Evidence Table for Ventral Hernia Cost Studies ......................................................... 71

FIGURES

Figure 1A. Literature Flow Chart .............................................................................................. 26

Figure 1B. Literature Flow Chart............................................................................................... 27

Figure 1C. Literature Flow Chart............................................................................................... 28

Figure 2. Cholecystectomy Intraoperative Outcomes ................................................................ 30

Figure 3. Cholecystectomy Short-term Outcomes ..................................................................... 32

Figure 4. Cholecystectomy Long-term Outcomes ..................................................................... 34

Figure 5. Inguinal Hernia Intraoperative Outcomes .................................................................. 48

Figure 6. Inguinal Hernia Postoperative Short-term Outcomes ................................................. 50

Figure 7. Inguinal Hernia Postoperative Long-term Outcomes ................................................. 52

Figure 8. Inguinal Hernia Postoperative Pain Outcomes ........................................................... 54

Figure 9. Ventral Hernia Intraoperative Outcomes .................................................................... 61

Figure 10. Ventral Hernia Postoperative Short-term Outcomes ................................................ 64

Figure 11. Ventral Hernia Postoperative Long-term Outcomes ................................................ 66

Figure 12. Ventral Hernia Postoperative Pain Outcomes .......................................................... 67

APPENDIX A. SEARCH STRATEGIES ................................................................................. 87

APPENDIX B. PEER REVIEWER COMMENTS AND RESPONSES ............................... 92

APPENDIX C. COCHRANE RISK OF BIAS TOOL ............................................................ 99

APPENDIX D. RISK OF BIAS IN NON-RANDOMISED STUDIES – OF 

INTERVENTIONS (ROBINS-I) ............................................................................................. 100

APPENDIX E. QUALITY ASSESSMENT FOR INCLUDED RCT STUDIES ................. 101

Cholecystectomy ...................................................................................................................... 101

Inguinal Hernia Repair ............................................................................................................. 101

APPENDIX F. QUALITY ASSESSMENT FOR INCLUDED OBSERVATIONAL 

STUDIES ................................................................................................................................... 102

Cholecystectomy ...................................................................................................................... 102

Inguinal Hernia Repair ............................................................................................................. 108

Ventral Hernia Repair .............................................................................................................. 112

APPENDIX G. EVIDENCE TABLES .................................................................................... 116

Cholecystectomy ...................................................................................................................... 116

Demographics and Pre-operative Factors ................................................................................ 116
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Intra-operative Outcomes ......................................................................................................... 128

Short-term Outcomes ............................................................................................................... 135

Long-term Outcomes ............................................................................................................... 143

Inguinal Hernia Repair ............................................................................................................. 149

Ventral Hernia Repair .............................................................................................................. 159

APPENDIX H. CITATIONS FOR EXCLUDED PUBLICATIONS ................................... 170
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EXECUTIVE SUMMARY

INTRODUCTION

General surgery procedures make up a large volume of operations performed in the US. For 

example there are approximately 1 million cholecystectomies and 800,000 ventral and inguinal 

hernia cases performed each year. Within this field we are experiencing dramatic recent growth 

in the number of robot-assisted cases. Questions about the utility of robot-assisted surgery as 

compared to laparoscopic and open surgery persist. In particular, does the use of the robot 

translate to better or similar clinical outcomes for patients? Are operating room times and length 

of stay comparable or improved with use of robot versus laparoscopic or open techniques? And 

what are costs of robot-assisted surgery and are they justified? Yet there is no consensus or 

guidelines on when to use which surgical approach and decisions are left up to individual 

practitioners or hospital leadership. To help clinicians, patients, and policymakers better assess

the appropriateness of robot-assisted compared to other surgical approaches, we were asked to 

conduct a systematic review of the literature on 3 of the most common general surgery 

operations: cholecystectomy, inguinal hernia repair, and incisional hernia repair. 

METHODS

This topic was developed in response to a nomination by Dr. Mark Wilson, National Director of 

Surgery, and Dr. William Gunnar, Executive Director, National Center for Patient Safety and 

former National Director of Surgery. Key questions were then developed with input from the 

topic nominator, the ESP coordinating center, the review team, and the technical expert panel 

(TEP).

The Key Questions are: 

KQ1A: What is the clinical effectiveness of robot-assisted surgery compared to conventional 

laparoscopic surgery for cholecystectomy?

KQ2A: What is the cost-effectiveness of robot-assisted surgery compared to conventional 

laparoscopic surgery for cholecystectomy?

KQ1B: What is the clinical effectiveness of robot-assisted surgery compared to conventional 

laparoscopic or open surgery for inguinal hernia repair? 

KQ2B: What is the cost-effectiveness of robot-assisted surgery compared to conventional 

laparoscopic or open surgery for inguinal hernia repair? 

KQ1C: What is the clinical effectiveness of robot-assisted surgery compared to conventional 

laparoscopic or open surgery for ventral hernia surgery?

KQ2C: What is the cost-effectiveness of robot-assisted surgery compared to conventional 

laparoscopic or open surgery for ventral hernia surgery? 
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Data Sources and Searches

We conducted separate searches for cholecystectomy, inguinal hernia repair, and ventral hernia 

repair. All searches included PubMed, Embase, and Cochrane (all databases) from 2010 to 

March 2020. For inguinal and ventral hernia repairs, Medline was also searched from 2010 to 

2020. 

Study Selection

Studies were included if they were randomized control trials or observational studies comparing 

robot-assisted surgery with either conventional laparoscopic or open surgical approaches for 

either of the included surgical procedures. We included all randomized controlled trials (RCTs) 

regardless of outcomes studied. We did not have sample size restrictions for cholecystectomy, 

but excluded studies with sample size <10 for inguinal and ventral hernia repairs. Specifically, 

each comparative arm needed to have a sample of more than 10. The cholecystectomy technique 

is very standard (with the exception of the number of ports used). However, both hernia repair 

techniques are widely variable including factors such as mesh location, size of hernia, type of 

sutures, use of tacks, use of sutureless mesh, etcetera, and these continue to evolve. These factors 

were not consistently reported. As such, we made the decision that the small studies (<10 sample 

size) would have the potential for substantial unmeasured bias. 

We also included publications of cost-effectiveness models or cost that compared robot-assisted

surgery with laparoscopic or open surgical approaches. 

Data Abstraction and Quality Assessment

We abstracted data on the following: study design, patient characteristics, sample size, 

intraoperative outcomes, postoperative outcomes, long-term functional outcomes, duration of 

follow-up, and data needed for the Cochrane Risk of Bias tool or Cochrane Risk of Bias In Nonrandomized Studies – of Interventions (ROBINS-I).

Data Synthesis and Analysis

Because the few RCTs were too heterogeneous, we did not conduct a meta-analysis of trials. 

Additionally, the observational studies were too clinically heterogeneous to support metaanalysis; hence, our synthesis is narrative. We assessed robot-assisted and laparoscopic approach 

for cholecystectomy, as open cholecystectomy is typically performed for cancer pathology or in 

the setting of significant inflammation or adhesive disease. We assessed robot-assisted, 

laparoscopic, and open approaches for inguinal and ventral hernia repairs. Of note, 

cholecystectomy (for benign disease) and most inguinal hernias are performed as outpatient 

surgery. 

Further, since there were limited RCTs and the observational studies had considerable 

differences between comparative arms (within and between studies), specific considerations for 

each of the 3 operations was warranted, in order to lessen confounding factors. Specifically, we 

needed to account for variations in patient factors and surgical techniques, which could impact 

clinical outcomes. For example, if a robot-assisted surgery study arm had a higher number of 

bilateral hernias than the laparoscopic group, this could account for longer operative times or 

higher rate of complications. Studies that performed matching (propensity matching) in our 
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review would account for a number of important variables but typically did not control for all 

relevant patient or technical factors (ie, extent of fascial closure, hernia size, etc). Of note, our 

research team made the following judgments to facilitate comparisons of the studies identified 

(which were mainly observational data). 

• For cholecystectomy, we present the data by grouping studies based on the number of 

surgical access ports used: 

o robot single-port compared to laparoscopic single-port or robot multi-port 

compared to laparoscopic multi-port; 

o robot single-port compared to laparoscopic multi-port; 

o robot compared to laparoscopic for those with unknown number of ports (in terms 

of outcomes). 

We did not identify any study reporting robot multi-port to laparoscopic single-port. 

• For inguinal hernia repair, we present the data by grouping studies where hernia laterality 

(unilateral or bilateral) was:

o known and at least <25% between comparative arms, or outcomes reported by 

laterality; 

o laterality not known. 

• For ventral hernia repair, we present the data by grouping studies that: 

o attempted matching on patient, hernia or technique factors;

o matching not performed. 

We used the criteria of the Grading of Recommendations Assessment, Development and 

Evaluation (GRADE) working group to assess the certainty of evidence across studies.

RESULTS

Results of Literature Search

For cholecystectomy, we identified 887 potentially relevant citations, of which 169 were 

included for abstract screening. A total of 47 publications were identified at full-text review as 

meeting initial inclusion criteria: RCT with cost and clinical data (n=1), RCTs with clinical data 

only (n=3), observational studies with cost data only (n=3), observational studies with clinical 

outcomes only (n=25), and observational studies with both clinical and cost data (n=15). 

For inguinal hernia repair, we identified 3,319 potentially relevant citations and 9 publications 

recommended by experts. From these, 185 were included for abstract screening. A total of 23 

publications were identified at full-text review as meeting initial inclusion criteria: RCT with 

clinical and cost data (n=1), observational studies with clinical outcomes only (n=18), and 

observational studies with both clinical and cost data (n=4). 

For ventral hernia repair, we identified 3,458 potentially relevant citations and 5 publications 

recommended by experts. From these, 369 were included for abstract screening. A total of 22 

publications were identified at full-text review as meeting initial inclusion criteria: RCT with 

clinical data only (n=1), observational study with cost data only (n=1), observational studies with 

clinical data only (n=15), and observations studies with both clinical and cost data (n=5). 
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Summary of Results for Key Questions

KQ1A: What is the clinical effectiveness of robot-assisted surgery compared to 

conventional laparoscopic surgery for cholecystectomy?

In general, operative room (OR) time was longer in patients treated with robot-assisted 

cholecystectomy compared to laparoscopic cholecystectomy. While not always statistically 

significant, data are consistent across RCTs and observational studies. There was no evidence of 

differences in total intraoperative complications or conversions, and most studies had point 

estimates close to the null value. Only 6 studies reported common bile duct injuries, and there 

was no difference between robot-assisted cholecystectomy and laparoscopic cholecystectomy. 

There was no evidence that conversion rates were different between the approaches, regardless 

of the port comparisons. Most studies did not demonstrate a significant difference in length of 

stay (LOS), postoperative complications, or surgical site infections (SSI). However, there may be 

a trend toward lower LOS for single-port robot-assisted cholecystectomy to single-port 

laparoscopic approach. Postoperative pain was reported inconsistently among the studies and did 

not demonstrate a pattern favoring robot-assisted or laparoscopic surgery. There may also be a 

trend toward a lower readmission rate for the robot-assisted approach. The rate of developing a 

postoperative incisional hernia may be higher in single-port robot-assisted cholecystectomy. All 

of the studies that demonstrated a statistically significant difference in incisional hernia rate 

compared single-port robot-assisted cholecystectomy to multi-port laparoscopic 

cholecystectomy. Studies that compared single-port robot-assisted cholecystectomy and singleport laparoscopic cholecystectomy or multi-port robot-assisted to multi-port laparoscopicassisted did not report different rates for incisional hernias. This may be because the single-port 

approach with robot-assisted cholecystectomy or laparoscopic cholecystectomy involves a larger 

incision and has a higher risk for developing an incisional hernia. 

KQ2A: What is the cost-effectiveness of robot-assisted surgery compared to 

conventional laparoscopic surgery for cholecystectomy?

While there are a number of studies comparing the cost-effectiveness of robot-assisted versus

laparoscopic surgery for cholecystectomy, all had significant limitations, primarily surrounding 

the cost methodology. None were formal cost-effectiveness analysis studies. Nevertheless, there 

was an almost unanimous finding, including in the randomized data, that the robot-assisted

approach is more expensive than the laparoscopic approach. We therefore have moderate 

certainty that robot-assisted surgery is more expensive than laparoscopic cholecystectomy. How 

much more expensive is not known with precision. The lack of cost-effectiveness studies 

suggests that weighing the balance between the added cost against possible benefits and risks of 

the robot-assisted approach is not possible 

KQ1B: What is the clinical effectiveness of robot-assisted surgery compared to 

conventional laparoscopic or open surgery for inguinal hernia repair? 

Operative room time was longer in patients treated with robot-assisted inguinal hernia repair 

compared to laparoscopic and open repair, particularly for unilateral repairs. There was no

evidence of a difference in conversions for the 3 studies reporting conversion rates between 

robot-assisted and laparoscopic approaches. In terms of LOS, there may be a signal of a small 

benefit favoring the robot-assisted approach compared to open surgery for inpatient stays. There 

does not appear to be a signal of benefit with regard to SSI for the robot-assisted approach 
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compared to laparoscopic or open surgery. There may be a small signal of benefit for lower 

readmissions with the robot-assisted approach for bilateral and unilateral hernia repairs as 

compared to open approach. Most studies demonstrated no difference among approaches when 

assessing complications and postoperative pain. There was no evidence of difference in hernia 

recurrence among all approaches. 

KQ2B: What is the cost-effectiveness of robot-assisted surgery compared to 

conventional laparoscopic or open surgery for inguinal hernia repair?

Five studies compared costs of robot-assisted to laparoscopic or open surgery for inguinal hernia 

repair. All had significant limitations, primarily surrounding the cost methodology. Robotassisted surgery was more expensive in all 5 studies as compared to laparoscopic or open 

inguinal hernia repair. However, we judged this evidence to be of moderate certainty. 

Additionally, no formal cost-effectiveness analysis was performed, and thus no definitive 

conclusion regarding cost can be made.

KQ1C: What is the clinical effectiveness of robot-assisted surgery compared to 

conventional laparoscopic or open surgery for ventral hernia repair?

Operative room time was significantly longer in robot-assisted ventral hernia repair compared to 

both the laparoscopic and open approaches in all but 1 of the included studies. There was no 

evidence of difference in intraoperative complication rate among the approaches. There is a 

possible trend toward decreased transfusion rate with robot-assisted surgery compared to 

laparoscopic and open repairs, with 1 study demonstrating a significant difference favoring 

robot-assisted surgery and another demonstrating no difference. Conversion rate may have a 

small signal of being lower with robot-assisted surgery compared to the laparoscopic approach.

Robot-assisted ventral hernia repair appears to significantly decrease LOS compared to open 

repair; however, this difference may be less than when compared to laparoscopic repair. There is 

a likely decrease in postoperative complication rate following robot-assisted repair compared to 

both open and laparoscopic approaches based on the results of matched studies (unmatched 

studies do not support this trend). There may be a small signal of decreased SSI rates in the 

robot-assisted group as compared to the open approach. There is no evidence of difference in the 

following specific postoperative events: readmission, mortality, or postoperative pain rates 

among the surgical approaches. Finally, in terms of hernia recurrence, 1 matched study showed 

decreased rate as compared to laparoscopic surgery and 1 study did not. The 1 matched study for 

open surgery showed no difference.

KQ2C: What is the cost-effectiveness of robot-assisted surgery compared to 

conventional laparoscopic or open surgery for ventral hernia repair?

There are a handful of cases comparing the costs of robot-assisted to laparoscopic or open 

surgery for ventral hernia repair. All had significant limitations, primarily surrounding the cost 

methodology. However, 4 of the 6 studies reported that the robot-assisted approach was more 

expensive than either the laparoscopic or open approach (with large effect size) and the other 2

studies reported no difference in cost as compared to laparoscopic repair. As seen for 

cholecystectomy and inguinal hernia, no cost-effectiveness studies were identified and definitive 

conclusions cannot be made. 
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DISCUSSION

Key Findings and Strength of Evidence

Robot-assisted surgery for cholecystectomy, inguinal hernia repair, and ventral hernia repair is 

associated with longer OR times, in general, and the strength of evidence ranged from high to 

low, depending on the procedure. The differences are possibly related to the additional docking 

times needed for the robot-assisted console. Of note, there is variability with how OR time was 

measured across the studies. Similarly, there is a learning curve effect as surgeons become more 

experienced on the robot over time, which some of the studies were likely capturing and others 

specifically addressed. For other intraoperative events, there were small signals noted favoring 

less transfusions and conversions to open procedure for ventral hernia repair. However, the 

strength of evidence was low. For postoperative LOS, there were trends favoring each procedure: 

moderate certainty in evidence for ventral hernia repair, and moderate certainty for LOS for 

inguinal hernia repair. For inguinal and ventral hernia repairs, there are signals that some 

postoperative complications may be lower with the robot-assisted approach for these procedures

as compared to open. Likewise, there is evidence that a number of other postoperative events are 

lower for ventral hernia repair – specifically, postoperative complications and SSI (as compared 

to open approach) – but these both had low certainty of evidence. In general, the certainty of 

evidence is low or very low, as there were few RCTs. Readmissions may also be lower for robotassisted approach for cholecystectomy (low certainty of evidence). 

On the crucial issues of long-term outcomes, such as recurrences or chronic pain (for the 2 types 

of hernia repairs), data are too sparse and imprecise to reach any conclusions. Overall, the 

comparator arms for these procedures were limited by differences in patient factors, hernia 

factors (ie, laterality, hernia size), and varying techniques (ie, type of fascial closure).

Cost studies found higher expense associated with robot-assisted surgery, which was consistently 

reported, but these are limited by the wide variability in the methodologies and definitions used

to measure cost. Formal cost-effectiveness for these 3 procedures has not been estimated and 

definitive conclusions regarding the balance between benefits, risks, and cost cannot be made. If 

efficiencies in the robot-assisted approach improve over time (as the learning curve is achieved), 

this in turn may bring down some of the costs. Unfortunately, we are not aware of any robotassisted cost data within VA, but utilization data are available and this may serve as a first step 

towards future research in this area.

Applicability

There were a limited number of studies specific to VA populations; 1 was on cholecystectomy, 1 

was on inguinal hernia repair, and none on ventral hernia repair. As such, we are unable to make 

specific conclusions from VA data. 

Non-VA studies account for most of our evidence. Applicability of these results to VA 

populations may depend on both the similarity of the patients studied to VA patients and the 

experience of the surgical teams using robot-assisted surgery to VA surgical team experience. 

However, the benefits for robot-assisted approach may still be realized despite patient-level 

differences (VA patient population has greater burden of comorbidities than the general 

population), which will need to be confirmed in future studies. Urologic surgery has been widely 
Robot-assisted Procedures in General Surgery Evidence Synthesis Program

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adopted in the VA, so this experience for the staff may translate into an easy implementation to 

the robot-assisted general surgery field.

Research Gaps/Future Research

Numerous research gaps are apparent. There is a need for randomized data or propensity 

matching that addresses patient- and technique-related factors. The variability in the use of the 

robot-assisted approach based on these factors currently limits the ability to compare across 

study arms, as variations at baseline or differences in how the operation was performed are large 

and may likely be responsible for realized clinical differences or lack thereof. Importantly, there 

are advantages of the robot-assisted approach that are clear and notable – enhanced, threedimensional visualization, augmented dexterity and range of motion, and reduction of tremor, to 

name a few. The heterogeneous nature of the studies limited the ability to show how these 

features translate into better clinical outcomes. Studies that control for key patient factors, case 

complexity, technical aspects of procedures, and surgeon experience may provide insight into 

this overarching question. Additionally, adequate long-term follow-up for certain outcomes is 

greatly needed. Several areas warrant specific discussion. 

Surgeon Learning Curve

The surgeon learning curve is a well-characterized surgical concept that has similarly been 

applied to robot-assisted surgery. As with any new platform, the need for training, practice, and 

experience is needed. Even open surgical procedures, such as pancreatectomy, suffer from 

inexperienced surgeons that require tutelage before displaying mastery of a technique. The 

advent of laparoscopy more than 30 years ago brought this concept more into the forefront and 

showed the impact of surgeon learning curves on clinical patient outcomes. Likewise, surgeon 

learning curve for robot-assisted cases is a multifaceted issue. Previous reviews found that the 

surgeon experience (ie, ability as a function of cases completed) is fluid as it has multiple phases 

and surgeons tend to add increasingly complex patient cases as they gain experience.

1 In our 

review, we found that 90% of the studies for robot-assisted cholecystectomy acknowledged the 

possibility of a learning curve; however only 5/46 provided data/assessment (and findings on OR 

time and incisional hernia occurrence were mixed). A learning curve impact may likely vary by 

procedure as well. Research assessing surgeon experience needs to include a variety of clinical 

outcomes, not just efficiency such as OR time. With emerging technologies, research should 

routinely comment on and address the potential impact the level of experience of the surgeon or 

surgeons played.

Resident Training

Robot-assisted surgery as an evolving technology is also changing how surgical residents are 

educated. Furthermore, faculty surgeons need to gain their own experience while balancing 

training residents. 1 recent survey of program directors by Tom et al found that a 92% of 

programs have residents participating in robot-assisted surgery, while 68% offer formal 

curriculum; 44% track residents’ robot-assisted experience; and about half (55%) recognize 

curriculum training completion. Another study also found wide variations “in requisite 

components, formal credentialing, and case tracking and role of simulation training”. There is 

also no standardized approach on how to incorporate this training based on level of trainee. 

Overall, there is a need to adopt a standardized training curriculum and document resident 

competency.
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Long-term Follow-up

Our work identified a lack of high quality evidence with adequate long-term follow-up and 

sufficient statistical power to properly assess clinical outcomes between the operative approaches 

for inguinal hernia repair and ventral hernia repairs. For hernia repairs, outcomes of interest need 

to include recurrent hernias beyond 1 year, long-term pain, and functional status. Only 1 small 

RCT was found for ventral hernia repair – none for inguinal hernia repair – and the 1 RCT only 

reported on 1 main outcome of interest. The data we found were too limited to provide 

conclusions in their regard. 

Cholecystectomy Research Gaps

Our review focused on the use of robot-assisted surgery for benign, elective gallbladder disease. 

However, there is a need for future studies on cholecystectomy for non-benign pathology and 

emergent cases. As the robot-assisted technique is becoming more common, certain institutions 

are beginning to use it for cancer cases and non-elective surgeries, which are notably more 

complex. Given the differences in patient populations that experience these indications and the 

higher rates of complications for non-elective surgeries, the results from our study may not be 

generalizable to these populations. In fact, the robot-assisted approach may prove to be 

particularly advantageous for these more complex cases. The study of differences in cancer 

outcomes, and morbidity, for robot-assisted versus laparoscopic and open surgery is essential. As 

such, future research may consider expanding this review to examine different indications for 

cholecystectomy. 

Inguinal Hernia and Ventral Hernia Repair Research Gaps

Specifically for hernia repairs, the robot-assisted approach may offer several technical 

advantages. For inguinal hernias, the potential for avoiding tacks or even the need for suturing 

mesh (sutureless mesh) may lead to less postoperative acute and chronic pain. For ventral hernia, 

the robot-assisted approach with improved suturing technique can also forego placement of tacks

as well as possibly decrease recurrent hernia formation. Unfortunately, these technical details 

were not uniformly available across the studies in our review and outcomes were typically not

reported by these factors. As such, it was not possible to determine their specific roles. 

Additionally, baseline pain was often not reported, perioperative quality of life and pain data 

were sparse, and long-term data on chronic pain and recurrence were rare. Standardized 

reporting in future work is needed in order to sufficiently assess pain outcomes, which needs to 

provide guidance on reporting technical aspects of the repair and requirements for clinical 

outcome assessment – specific time intervals, tools for assessing pain, and amount of pain 

medications taken.

Ergonomics for the Surgeon

An important issue that deserves study is the impact of the robot-assisted approach on the 

physical stress of the surgeon performing the operation. There is a high rate of musculoskeletal 

disorders attributed to poor ergonomics of laparoscopic surgery as well as the open approach. 

There are those that claim robot-assisted surgery ergonomics are superior, which translates into 

decreased physical stress and workload. However, there is also growing evidence that a 

prolonged time sitting at the robot-assisted console adds new physical challenges as well. 2 

recent studies reported physical discomfort and symptoms or poor posture in over half of 
Robot-assisted Procedures in General Surgery Evidence Synthesis Program

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surgeons. Although data is sparse, it would be a valuable area for future research. While 

challenging to study, the outcomes would need to be comparative, long-term (5 year plus) and 

would require assessing detailed quality of life, assessment of chronic physical injuries, and 

longevity of operating over a career.

Future Innovation in Surgical Robotics

An overwhelming number of the studies in our review used the da Vinci system from Intuitive 

(only 1 study used the Senhance robot). The robot-assisted field is changing soon, as a number of 

new robot-assisted platforms are becoming available; there are 8 with FDA approval and more 

pending approval. These will bring with them potentially new advantages (eg, improved 

computer optics, machine learning, and automation) and possibly new challenges (eg, different 

technology with new learning curves, unknown impact on patient outcomes). Future research 

will be critical to assess the differences between these technologies. With these new market 

forces, there is anticipation for reduced cost as well.

Conflict of Interest

It is notable that reporting bias in robot-assisted surgery research has been identified. A recent 

study found that author payments from Intuitive were not declared in more than half (52%) of 

robot-assisted surgery research, and they reported more positive findings as compared to those 

that did declare their conflict of interest (COI) payments. There is a need to ensure full disclosure 

of COI with more accountability, and journals may want to adopt standardized processes to 

achieve better transparency.

Costs

Lastly, the lack of well-designed comparative studies also limits evaluations of cost. There is a 

need for standardized approaches to assess cost, which would apply to all 3 of these robotassisted operations (ie, analytics approach, consistent definitions of cost, how upfront capital was 

accounted for, how to adjust for training staff, etc). Along these lines, formal cost-effectiveness 

studies that weigh the benefits and risks along with cost are needed. 

Conclusions

Across 3 common general surgery procedures there is evidence that OR time is longer for the 

robot-assisted approach, and some signals that select intraoperative and postoperative 

complications are more favorable with the robot-assisted approach, based on the operation. 

Overall, the studies were heterogeneous in terms of patient characteristics and how the 

operations were performed and strong conclusions cannot be made. Cost is probably higher 

across these procedures, but the balance between the added expense and potential gains in 

effectiveness are unknown, until we adopt better, standardized methods of assessment.
Robot-assisted Procedures in General Surgery Evidence Synthesis Program

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ABBREVIATIONS TABLE

ASA American Society of Anesthesiologists

BMI Body mass index

CCI Charlson comorbidity index

Chole Cholecystectomy

COI Conflict of interest

Comp Complications

dVSSC Da Vinci single-site cholecystectomy

EBDIT Earnings before depreciation, interest and tax

EBL Estimated blood loss

ED Emergency Department

Elective Elective surgery 

FDA Food and Drug Administration

F/U Follow-up

GRADE Grading of recommendations assessment, development and evaluation

IOC Intraoperative cholangiogram

Lap Laparoscopic approach

LC Laparoscopic cholecystectomy

LOS Length of stay

Mesh Repair with mesh

Narc Narcotic use

NIS National Inpatient Sample

OR Operating room or operating room time (where indicated)

Preop Preoperative

Primary Primary hernia repair

QOL Quality of life

RAC Robot-assisted cholecystectomy

RAS Robot-assisted surgery

RC Robotic cholecystectomy

RCT Randomized controlled trial

Recur Recurrence 

Reop Reoperation

SILC Single incision laparoscopic cholecystectomy

ROBINS-I Risk of bias in non-randomized studies- of interventions

Skin-to-skin Operating time from skin incision to skin closure

SSI Surgical site infection

SSO Surgical site occurrence

TAPP Transabdominal preperitoneal inguinal hernia repair

TEP Totally extra-peritoneal inguinal hernia repair

Txf Transfusion

TR Total recurrences

USD United States dollar
Robot-assisted Procedures in General Surgery Evidence Synthesis Program

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EVIDENCE REPORT

INTRODUCTION

Across the world, the adoption of robot-assisted surgery continues to increase, particularly for 

commonly performed general surgery procedures. In the US, the robot-assisted surgical platform 

was introduced in 1999 and by the end of 2017, over 3,000 robotic platforms were being used.2

While this new technology is becoming widespread, several questions about the utility of robotassisted surgery as compared to laparoscopic and open surgery persist. In particular, does the use 

of the robot translate to better or similar clinical outcomes for patients? Are operating room 

times and length of stay comparable or improved with use of robot as compared to laparoscopic 

or open techniques? These questions are critical to answer, both for patient safety and 

satisfaction, particularly in our current health care climate where hospitals and physicians must 

provide efficient care while maintaining the highest quality, all the while working to curtail 

costs. 

Cholecystectomy and hernia repair are commonly performed general surgery procedures. Over 1 

million cholecystectomies and 800,000 ventral and inguinal hernia repairs are completed

annually in the US.3,4

 Robot-assisted approaches to these procedures are becoming more 

common and accepted.

5 Specifically, inguinal and ventral hernia repairs are the most rapidly 

growing procedures for the robot-assisted platform in general surgery. For example, a cohort 

study from the Michigan Surgical Quality Collaborative Database shows an increase in robotassisted surgery general surgery procedures from 1.8% to 15.1% between 2012-2018.6

 In 

addition to multi-port laparoscopic and robot-assisted techniques, there has been a shift to singleport robot-assisted and laparoscopic approaches as well, which reduces the number of incisions 

for the patient.

7,8

Further fueling this debate is the economics of the robotic platform. The robotic platform 

requires a significant upfront investment, an annual maintenance contract, and ongoing 

instrument purchases, not to mention staff and training costs, advertising, and infrastructure 

upgrade expenses. Weighing these costs relative to the potential benefits of the robot-assisted 

approach, such as reduced length of stay, complications, readmissions, or improved patient 

centered outcomes, is critical in our climate of needing to curtail rising health care costs. 

In light of recent evidence in other surgical disciplines questioning the utility of the robotic 

platform, there is considerable need to understand the evidence surrounding the use of the 

robotic platform in general surgery. Few comprehensive systematic reviews addressing each of 

these procedures exist – specifically where the critical patient factors and technique differences 

are assessed. 

In summary, common general surgery procedures make up a large volume of the annual 

operations performed in the US, and we are experiencing dramatic recent growth in the number 

of robot-assisted surgery cases within this field. Yet there is no consensus or guidelines on when 

to use this surgical approach, and such decisions are left up to individual practitioners. To help 

clinicians, patients, and policymakers decide between robot-assisted and other surgical 

approaches for cholecystectomy, inguinal or ventral hernia repairs, we were asked to conduct a 

systematic review of the literature.
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METHODS 

TOPIC DEVELOPMENT 

This topic was developed in response to a nomination by Dr. Mark Wilson, National Director of 

Surgery, and Dr. William Gunnar, former National Director of Surgery. Key questions were then 

developed with input from the topic nominator, the ESP Coordinating Center, the review team, 

and the technical expert panel (TEP).

The Key Questions were:

KQ1A: What is the clinical effectiveness of robot-assisted surgery compared to conventional 

laparoscopic surgery for cholecystectomy?

KQ2A: What is the cost-effectiveness of robot-assisted surgery compared to conventional 

laparoscopic surgery for cholecystectomy?

KQ1B: What is the clinical effectiveness of robot-assisted surgery compared to conventional 

laparoscopic or open surgery for inguinal hernia repair?

KQ2B: What is the cost-effectiveness of robot-assisted surgery compared to conventional 

laparoscopic or open surgery for inguinal hernia repair?

KQ1C: What is the clinical effectiveness of robot-assisted surgery compared to conventional 

laparoscopic or open surgery for ventral hernia repair? 

KQ2C: What is the cost-effectiveness of robot-assisted surgery compared to conventional 

laparoscopic or open surgery for ventral hernia repair? 

Because the 3 surgical procedures were different, we constructed separate search strategies, 

inclusion and exclusion criteria for each procedure. 

The review was registered in PROSPERO and is awaiting registration number. 

SEARCH STRATEGY

We conducted separate searches for cholecystectomy, inguinal hernia, and ventral hernia. All 

searches included PubMed, Embase, and Cochrane (all databases) from 2010 to March 2020. For 

inguinal and ventral hernias, Medline was also searched from 2010 to 2020. The search used a 

broad set of common terms relating to "robotic surgical procedures" or “robotic-assisted” and 

“cost effectiveness”, and then the individual procedure-specific terms “inguinal hernia”, “ventral 

hernia” or “incisional hernia”, and “cholecystectomy”. Prior to 2010, robot-assisted procedures 

were not widely being performed and many surgeons were still in the so-called "learning curve". 

As such, our technical expert panel considered evidence from studies published prior to the year 

2010 to be insufficiently relevant to modern practice. While we still anticipated finding studies 

assessing or including the robot-assisted surgery learning curve, this later search date will help 

lessen that occurrence. See Appendix A for complete search strategy. 
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STUDY SELECTION

Multiple team members working independently screened the titles of retrieved citations. For 

cholecystectomy, MMG and RS; for inguinal hernia repair, LY and MMG; for ventral hernia 

repair, LY, RS, MG, and MMG. 

For titles deemed relevant by at least 1 person, abstracts were then screened independently in 

duplicate by multiple team members working in pairs. For cholecystectomy, RS and MMG; for 

inguinal hernia repair, LY, AT, and MMG; for ventral hernia repair, LY and MMG. 

All disagreements were reconciled through group discussion. Full-text review was conducted in 

duplicate by 2 independent team members, with any disagreements resolved through discussion. 

For cholecystectomy, RS and MM; for inguinal hernia repair, LY and AT; for ventral hernia 

repair, LY and MMG. 

Studies were included at either the abstract or the full-text level if they were randomized control 

trials or observational studies comparing robot-assisted surgery with either laparoscopic or open 

surgical approaches for any of the included surgical procedures. We also included publications of 

cost-effectiveness models that compared robot-assisted surgery with laparoscopic or open 

surgical approaches. We included all RCTs regardless of outcomes studied. We did not have 

sample size restrictions for cholecystectomy, but excluded studies with sample size <10 for 

inguinal and ventral hernia repairs. The cholecystectomy technique is very standard (with the 

exception of the number of ports). However, both hernia repair techniques are widely variable 

including factors such as mesh location, size of hernia, type of sutures, use of tacks, use of 

sutureless mesh, etcetera, and these continue to evolve. These factors were not consistently 

reported. As such, we made the decision that the small studies (<10 sample size) would have the 

potential for substantial unmeasured bias. 

DATA ABSTRACTION

Data extraction was completed in duplicate. All discrepancies were resolved with full group 

discussion. We abstracted data on the following: study design, patient characteristics, sample 

size, intraoperative outcomes, postoperative outcomes, long-term functional outcomes and 

cancer outcomes, duration of follow-up, and data needed for the Cochrane Risk of Bias tool or 

Cochrane Risk Of Bias In Non-randomized Studies – of Interventions (ROBINS-I). 

QUALITY ASSESSMENT

Randomized controlled trials were assessed for quality (risk of bias) with the Cochrane Risk of 

Bias tool.9

 This tool requires an assessment of whether a study is at high or low (or unknown) 

risk of bias in 7 domains: random sequence generation, allocation concealment, blinding of 

participants and personnel, blinding of outcome assessment, incomplete outcome data, selective 

outcome reporting, and other (See Appendix C for tool; Appendix E for table). We used the Risk

Of Bias In Non-randomized Studies – of Interventions (ROBINS-I) for observational studies.10

This tool requires an assessment of whether a study is at critical, serious, moderate, or low risk of 

bias (or no information) in 7 domains: confounding, selection bias, bias in measurement 

classification of interventions, bias due to deviations from intended interventions, bias due to 

missing data, bias in measurement of outcomes, and bias in selection of the reported result (see 

Appendix D for tool; Appendix F for table). 
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The review team operationalized the 7 domains in the following manner: 

Confounding factors 

• Low: if patients have similar baseline characteristics, OR if significantly different, are 

propensity matched

• Serious: if baseline data is not explicitly stated

Selection bias 

• Low: if consecutive series, OR if *likely* consecutive from a database study

Bias in measurement classification of interventions & bias due to deviation from intended 

interventions 

• Low: by nature of the included studies 

Bias due to missing data 

• Studies with outcomes of 30 days or less were assumed to be 100% follow-up 

• Moderate if loss to follow-up is unclear; serious if follow-up is reported, but low 

• If studies exclude missing data in their study design then serious selection bias, but low 

for bias due to missing data 

• If studies report an n-value in postoperative/long-term outcome tables that is consistent 

with their original n-value then that implies 100% follow-up 

• Low: if no/minimal loss to follow-up

Bias in measurement of outcomes 

• Split up outcomes by risk if there are differences

• OR times: likely low risk due to retrospective nature of most of these studies

• Pain: moderate risk due to patient subjectivity, lack of concealment, possible physician 

counseling, etc.

Bias in selection of the reported result 

• Low: if authors report all available data, especially data with no significant differences

• Depends on the purpose and intended outcomes of the study, and whether other similar 

studies report omitted outcomes

DATA SYNTHESIS

Because the RCTs were too heterogeneous, we did not conduct a meta-analysis of trials. The 

observational studies were too clinically heterogeneous to support meta-analysis; hence, our 

synthesis is narrative.

We assessed robot-assisted and laparoscopic approach for cholecystectomy, as open 

cholecystectomy is typically performed for only cancer pathology. Therefore, robot-assisted

cholecystectomy to open cholecystectomy is not clinically relevant. We assessed robot-assisted, 

laparoscopic, and open approaches for inguinal and ventral hernia repairs. Of note, 

cholecystectomy (for benign disease) and most inguinal hernias are performed as outpatient 

surgery. 
Robot-assisted Procedures in General Surgery Evidence Synthesis Program

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Further, since there were limited RCTs, specific considerations for each of the 3 operations types 

were warranted, in order to account for a number of potential differences between study arms. 

Specifically, we needed to assess for within-study variations in patient factors and varying 

surgical techniques, which could confound effect differences in clinical outcomes. For example, 

if a robot-assisted surgery study arm had a higher number of bilateral hernias than the 

laparoscopic group, this in and of itself could potentially be responsible for longer operative 

times or higher rate of complications. Studies that performed matching (propensity matching) in 

our review accounted for a number of important variables but typically did not control for all 

relevant patient or technique factors (ie, extent of fascial closure, hernia size, etc). 

Specifically, our research team made the following judgments to allow for the most optimal 

comparisons of the studies identified (which were mainly observational). 

• For cholecystectomy, we present the data by grouping studies based on the number of 

surgical access ports used: 

o robot single-port compared to laparoscopic single port or robot multi-port 

compared to laparoscopic multi-port; 

o robot single-port compared to laparoscopic multi-port; 

o robot compared to laparoscopic for those with unknown number of ports (in terms 

of outcomes). 

We did not identify any study reporting robot multi-port to laparoscopic single-port. 

• For inguinal hernia repair, we present the data by grouping studies where hernia laterality 

(unilateral or bilateral) was:

o known and at least <25% between comparative arms, or outcomes reported by 

laterality; 

o laterality not known. 

• For ventral hernia repair, we present the data by grouping studies that: 

o attempted matching on patient, hernia, or technique factors;

o matching not performed. 

RATING THE BODY OF EVIDENCE 

We used the criteria of the Grading of Recommendations Assessment, Development and 

Evaluation (GRADE) working group.11 GRADE assessing the certainty of the evidence based of 

the assessment of the following domains: risk of bias, imprecision, inconsistency, indirectness, 

and publication bias. This results in categories as follows:

High: We are very confident that the true effect lies close to that of the estimate of the effect.

Moderate: We are moderately confident in the effect estimate. The true effect is likely to be close 

to the estimate of the effect, but there is a possibility that it is substantially different.

Low: Our confidence in the effect estimate is limited. The true effect may be substantially 

different from the estimate of the effect.
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Very low/Insufficient: We have very little confidence in the effect estimate. The true effect is 

likely to be substantially different from the estimate of effect.

PEER REVIEW

A draft version of the report was reviewed by technical experts and clinical leadership. Reviewer 

comments and our response are documented in Appendix B. 
Robot-assisted Procedures in General Surgery Evidence Synthesis Program

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RESULTS

For cholecystectomy, we identified 887 potentially relevant citations, of which 169 were 

included at the abstract screening. From these, a total of 90 abstracts were excluded. Excluded 

abstracts were categorized as wrong comparison (n=54), systematic review (n=14), 

review/editorial (n=14), no outcome of interest (n=1), and other (n=7). This left 79 publications 

for full-text review, of which 32 were excluded for the following reasons: wrong comparison 

(n=4), no clinical data (n=3), no outcome of interest (n=4), review/editorial (n=8), other (n=2), 

and duplicate (n=11). A full list of excluded studies from the full-text review is included in 

Appendix H. A total of 47 publications were identified at full-text review as meeting initial 

inclusion criteria: RCT with cost and clinical data (n=1), RCTs with clinical data only (n=3), 

observational studies with cost data only (n=3), observational studies with clinical outcomes only 

(n=25), and observational studies with both clinical and cost data (n=15). Descriptions of 

included publications are available in the Evidence Table (Appendix G).

For inguinal hernia repair, we identified 3,319 potentially relevant citations and 9 publications

recommended by experts. From these, 185 were included for abstract screening. A total of 143

abstracts were excluded, categorized as wrong comparison (n=129), no outcome of interest 

(n=1), other (n=6), systematic review (n=3), review (n=1), and duplicate (n=3). This left 42

publications for full-text review, of which 19 were excluded for the following reasons: wrong 

comparison (n=2), no outcome of interest (n=6), no clinical data (n=3), procedure (n=1), 

systematic review (n=1), review/editorial (n=2), duplicate (n=3), and unavailable (n=1). A full 

list of excluded studies from the full-text review is included in Appendix H. A total of 23

publications were identified at full-text review as meeting initial inclusion criteria: RCT with 

clinical and cost data (n=1), observational studies with clinical outcomes only (n=18), and 

observational studies with both clinical and cost data (n=4). Eleven studies had known hernia 

laterality that were similar distribution between study arms (<25% difference in laterality). While 

6 studies with known laterality had >25% difference between comparison groups, for the other 6

studies, laterality was unknown or not reported (between the comparative arms). Descriptions of 

included publications are available in the Evidence Table (Appendix G).

For ventral hernia repair, we identified 3,458 potentially relevant citations and 5 publications

recommended by experts. From these, 369 were included for abstract screening. A total of 321 

abstracts were excluded, categorized as wrong comparison (n=306), review/editorial (n=8), no 

outcome of interest (n=8), systematic review (n=1), and duplicate (n=3). This left 48 publications 

for full-text review, of which 26 were excluded for the following reasons: case series with 

sample less than 10 (n=2), comparison (n=6), no outcome of interest (n=7), sample size less than 

10 in each arm (n=2), review/editorial (n=1), systematic review (n=1), duplicate (n=6), and 

unavailable (n=1). A full list of excluded studies from the full-text review is included in 

Appendix H. A total of 22 publications were identified at full-text review as meeting initial 

inclusion criteria: RCT with clinical data only (n=1), observational study with cost data only 

(n=1), observational studies with clinical data only (n=15), and observational studies with both 

clinical and cost data (n=5). 7 of the observational studies reported matched data and 14 had 

unmatched data. Descriptions of included publications are available in the Evidence Table 

(Appendix G).
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THE RISK OF BIAS OF STUDIES

For cholecystectomy, there were 4 RCTs and 40 observational studies. The RCTs in general 

were assessed to have an overall low risk of bias. Overall, the majority of the observational 

studies had high to moderate risk of bias, except for those with propensity matching (n=4). 

For inguinal hernia repair, 1 RCT and 22 observational studies met inclusion criteria, including 6

abstracts. The RCT was assessed to have an overall moderate risk of bias due to the singleblinded design, unclear allocation concealment and blinding of outcome assessment, and 

potential for author bias due to the significant funding to multiple authors by the robot 

manufacturer. Overall, the majority of the observational studies had a high risk of confounding 

bias, as only 5 studies were propensity matched. Large differences (>25%) in or lack of reporting 

of the proportion of unilateral to bilateral inguinal hernia repairs also introduced confounding 

bias in 10 observational studies. Selection bias for the majority of studies was low; however, 8

studies were judged to have greater risk of bias due to study-specific patient exclusion criteria.

Several papers also had author disclosures due to involvement with Intuitive Surgical Inc. 

Finally, we identified 1 study that conducted a random sample from a web-based research panel 

and was subject to numerous methodological limitations due to low response rate and high recall 

bias.

12

For ventral hernia repair, 1 RCT and 20 observational studies met inclusion criteria. The RCT 

was a conference abstract of a small sample of patients and was judged to have an overall high 

risk of bias due to lack of allocation concealment, blinding of patients and personnel, blinding of 

outcome assessment, selective reporting, and use of self-reported outcomes, such as quality of 

life. The majority of the observational studies had a high risk of confounding bias, as only 8

studies were propensity matched, and of the matched studies, there was variation on which 

variables were being matched (eg, patient characteristics vs hernia size). Selection bias was 

overall low. 

For all procedures, bias in the measurement classification of interventions, bias due to deviation 

from intended interventions, and bias in selection of the reported result were generally low. Bias 

due to missing data was overall low, as most studies only reported short-term (≤ 30 day) 

outcomes, which were presumed to have minimal loss to follow-up. Studies with long-term 

outcomes had a higher risk of bias due to missing data if follow-up rates were low or not 

reported. For bias in measurement of outcomes, self-reported outcomes relating to pain and 

quality of life had a moderate risk of bias due to the subjectivity of these measurements, while 

objective assessments of pain, such as narcotic use, had a low risk of bias. Other outcomes, such 

as length of stay, complications, and OR time, had a low risk of bias.
Robot-assisted Procedures in General Surgery Evidence Synthesis Program

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Figure 1A. Literature Flow Chart 

CHOLESCYSTECTOMY 

Total title screened: 887

Abstracts reviewed: 169

Excluded: 718

Abstracts reviewed: 79

Excluded = 90 references 

Comparison: 54

SR: 14

Review/editorial: 14

Outcome: 1

Other: 7

Excluded = 32 references

Comparison: 4 

No clinical data: 3 

Outcome: 4

Review/editorial: 8

Other: 2 

Duplicate: 11

Observational 

studies

clinical and 

cost data: 15

clinical data 

only: 25

Included publications: 47

RCTs

clinical and 

cost data: 1

clinical data 

only: 3

cost data only: 

3 
Robot-assisted Procedures in General Surgery Evidence Synthesis Program

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Figure 1B. Literature Flow Chart 

INGUINAL HERNIA REPAIR

Total title screened: 3319

Abstracts reviewed: 185 

Excluded: 3143

Excluded = 143 references

Comparison: 129

Outcome: 1

Other: 6

Review: 1

SR: 3

Duplicate: 3

Full text reviewed: 42

Expert recommendation: 9

Excluded = 19 references

Comparison: 2

Outcome: 6 

No clinical data: 3 

Procedure: 1

SR: 1

Review/editorial: 2

Duplicate: 3 

Unavailable: 1

RCT

clinical and 

cost data: 1

Observational 

studies

clinical and cost 

data: 4

clinical data 

only: 18 

Included publications: 23
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Figure 1C. Literature Flow Chart 

VENTRAL HERNIA REPAIR

Total title screened: 3458

Abstracts reviewed: 369

Excluded: 3094

Excluded: 321

Comparison: 306

Review/Editorial: 8 

Outcome: 3

SR: 1

Duplicate: 3

Abstracts reviewed: 48

Excluded = 26 references

Case series n<10: 2

Comparison: 6

Outcome: 7 

Sample size <10 in each arm: 2

Review/editorial: 1

Systematic review: 1

Duplicate: 6

Unavailable: 1

Included publications: 22

Observational 

studies

clinical and 

cost data: 5 

clinical data 

only: 15 

Expert recommendation: 5

RCTs

clinical data 

only: 1

cost data only: 

1 
Robot-assisted Procedures in General Surgery Evidence Synthesis Program

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KEY QUESTION 1A – CHOLECYSTECTOMY: What is the clinical 

effectiveness of robot-assisted surgery compared to conventional 

laparoscopic surgery for cholecystectomy?

We identified 44 publications that met the inclusion criteria; 4 studies were randomized trials,13-

16 and the remaining studies were observational. 7 studies compared multi-port robot-assisted 

cholecystectomy with multi-port laparoscopic cholecystectomy,14,17-22 including 1 RCT14; 12

compared single-port robot-assisted cholecystectomy with multi-port laparoscopic 

cholecystectomy,15,16,23-32 including 2 RCTs15,16; and 11 compared single-port robot-assisted 

cholecystectomy with single-port laparoscopic cholecystectomy,33-43 including 1 RCT.13 1 study 

compared 3 arms: single-port robot-assisted cholecystectomy, multi-port robot-assisted 

cholecystectomy, and single-port laparoscopic cholecystectomy.44 Thirteen studies either 

grouped all (single and multi-port) robot-assisted and laparoscopic cholecystectomies in separate 

groups or did not specify if the robot and laparoscopic arms were single-port, multi-port, or 

both.45-57 The studies varied in size from 20 to 735,537 patients.

Figure 2 presents graphically the results for 4 intraoperative outcomes: operating room (OR)

time, complications, conversion to open cholecystectomy (or conversion from robot-assisted to

laparoscopic cholecystectomy), and common bile duct injury. In the 4 RCTs, OR time was

consistently longer for robot-assisted cholecystectomy procedures, although these differences

were only statistically significant in 2 studies (one compared single-port robot-assisted 

cholecystectomy to single-port laparoscopic cholecystectomy15 and the other multi-port robotassisted cholecystectomy to multi-port laparoscopic cholecystectomy).

14 From the observational

studies, robot-assisted cholecystectomy took longer to perform in the great majority of studies

with most of these differences being statistically significant. Of the studies that demonstrated a

shorter OR time in the robot cohort, only 2 were statistically significant, and they compared

single-port robot-assisted cholecystectomy and single-port laparoscopic cholecystectomy.

37,41

For the outcomes of intraoperative complications, bile duct injury as its own outcome, or

conversion rates, differences between robot-assisted cholecystectomy and comparison

procedures were minimal to none, both in the RCTs and in the observational studies.
Robot-assisted Procedures in General Surgery Evidence Synthesis Program

30

Figure 2. Cholecystectomy Intraoperative Outcomes

Graphed is the point estimate and 95% confidence intervals for the difference in the indicated outcome between 

robot-assisted cholecystectomy and laparoscopic approach. RCTs are listed in the left-hand side, while observational 

studies are listed on the right-hand side.
Robot-assisted Procedures in General Surgery Evidence Synthesis Program

31

Figure 3 presents graphically the results of 6 short-term outcomes: LOS, all postoperative

complications, surgical site infections, pain immediately following surgery, pain 1-30 days, and

readmission rate. 3 out of 4 RCTs13,15,16 reported on LOS, and this was significantly shorter in 1

study comparing the single-port robot-assisted cholecystectomy patients with single-port

laparoscopic cholecystectomy patients.

13 In the other 2 RCTs, both of which compared singleport robot-assisted surgery to multi-port laparoscopic surgery, there was no significant difference

in LOS.

15,16 In general, patients across all the RCTs and observational studies were discharged

within 1 to 2 days without a suggestive pattern favoring any particular procedure. There were no

significant differences in total complications or surgical site infections between procedures, and

most point estimates were on or extremely close to the null value of no difference. There was

somewhat more variation in point estimates of differences in the 2 pain outcomes, but no clear

pattern favoring 1 procedure over another. Twelve observational studies reported readmissions,

and 4 of these studies demonstrated a significantly higher readmission rate in the laparoscopic

surgery patients.20,44,54,57 Of those 4 studies, 1 had compared single-port robot-assisted 

cholecystectomy, multi-port robot-assisted cholecystectomy, and single-port laparoscopic 

cholecystectomy.

44
Robot-assisted Procedures in General Surgery Evidence Synthesis Program

32

Figure 3. Cholecystectomy Short-term Outcomes

Graphed is the point estimate and 95% confidence intervals for the difference in the indicated outcome between 

robot-assisted cholecystectomy and laparoscopic approach. RCTs are listed in the left-hand side, while observational 

studies are listed on the right-hand side.
Robot-assisted Procedures in General Surgery Evidence Synthesis Program

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Figure 4 presents graphically the results of the only long-term outcome, incisional hernia rates.

This outcome is less frequently reported than the short-term outcomes and is included in only 2 

RCTs13,16 and 10 observational studies.23-25,27,30,32,36,39,41,51 The 2 RCTs13,16 reported no

statistically significant differences, but the 95% confidence intervals are very wide, and clinically

important differences cannot be excluded. 3 observational studies23,25,30 found higher incisional

hernia rates in the single-port robot-assisted cholecystectomy patients compared to the multi-port

laparoscopic cholecystectomy patients. The point estimate of effect for these 3 observational

studies is within the 95% confidence interval of the 1 RCT of this comparison,16 and in fact quite

close to the RCT point estimate of effect. We interpret these findings as a possible signal that this

long-term outcome may be worse in single-port robot-assisted cholecystectomy than multi-port

laparoscopic cholecystectomy. In the remainder of the studies that reported on incisional hernia

formation, there was no significant difference between robot-assisted cholecystectomy and

laparoscopic cholecystectomy cohorts; 4 out of 6 of those studies compared single-port robotassisted cholecystectomy to single-port laparoscopic cholecystectomy.
Robot-assisted Procedures in General Surgery Evidence Synthesis Program

34

Figure 4. Cholecystectomy Long-term Outcomes

Graphed is the point estimate and 95% confidence intervals for the difference in the indicated outcome between 

robot-assisted cholecystectomy and laparoscopic approach. RCTs are listed in the left-hand side, while observational 

studies are listed on the right-hand side.
Robot-assisted Procedures in General Surgery Evidence Synthesis Program

35

Summary of Findings

In general, OR time was longer in patients treated with robot-assisted cholecystectomy compared 

to laparoscopic cholecystectomy. While not always statistically significant, data are consistent 

across RCTs and observational studies, and also consistent with differences in OR time seen 

between other robot-assisted procedures and their laparoscopic or open counterparts. There was

no evidence of differences in total intraoperative complications in total intra-operative 

complications or conversions, and most studies had point estimates close to the null value. Only 

5 studies reported common bile duct injuries, and there was no evidence of differences between 

robot-assisted cholecystectomy and laparoscopic cholecystectomy. There was no evidence across 

most studies of differences in LOS, post-operative complications, or SSI. Pain was reportedly 

inconsistently among the studies and there was no evidence favoring robot-assisted or 

laparoscopic surgery. The lack of difference in outcomes between techniques could in part be

related to patient selection and the type of gallbladder pathology for which each technique was 

used. Additionally, studies capturing surgeons’ learning curve of the robot-assisted platform

could factor in as well. The rate of incisional hernia may be higher in single-port robot-assisted 

cholecystectomy as compared to multi-port laparoscopic, a

All studies that demonstrated a statistically significant difference in incisional hernia rate 

compared single-port robot-assisted cholecystectomy to multi-port laparoscopic 

cholecystectomy. There was also no evidence of differences in the rate of incisional hernia rates 

for single-port robot-assisted and single-port laparoscopic cholecystectomy. This may be because 

the single-port approach with robot-assisted cholecystectomy or laparoscopic cholecystectomy

involves a larger incision and confers a higher risk for developing an incisional hernia.

Certainty of Evidence for Key Question 1A

We judged the certainty of evidence for most outcomes as being moderate, with evidence from 

RCTs and from observational studies mainly in agreement on the direction of effect. We judged 

the evidence for most outcomes as imprecise, leading to a reduction in the certainty of evidence 

(from high to moderate). OR time outcomes for robot-assisted compared to laparoscopic 

cholecystectomy was deemed moderate because of imprecision. We judged the results for 

intraoperative complications as moderate due to some imprecision, and common bile duct injury 

was considered low because of imprecision and sparsity of data. We judged the certainty of 

evidence for conversion rate between robot-assisted cholecystectomy and laparoscopic 

cholecystectomy as high, based on the RCT data. We judged LOS as imprecise but moderate, 

since 3RCTs reported this result. All postoperative complications and surgical site infection as 

moderate certainty of evidence due to imprecision. We judged the certainty of evidence for 

readmission outcome between robot-assisted cholecystectomy and laparoscopic cholecystectomy

as low. We judged the certainty of evidence for pain as low due to inconsistent and imprecise 

results. Certainty of evidence for postoperative incisional hernia formation between robotassisted cholecystectomy and laparoscopic cholecystectomy was deemed low due to 

inconsistency among the comparison groups and imprecision.
Robot-assisted Procedures in General Surgery Evidence Synthesis Program

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Table 1. Certainty of Evidence for Cholecystectomy Studies

Outcome Study Limitations Consistency Directness Precision

Certainty of 

Evidence

Intra-operative

OR Time

Robot > Laparoscopic

RCT: Low

Observational studies: 

High

Consistent Direct Imprecise Moderate

Complications

Robot = Laparoscopic

RCT: Low

Observational studies: 

High

Consistent Direct Imprecise Moderate

Common Bile Duct 

Injury

Robot = Laparoscopic

RCT: Low

Observational studies: 

Low

Consistent Direct Imprecise Moderate

Conversions

Robot = Laparoscopic

RCT: Low

Observational studies: 

High

Consistent Direct Precise High

Short-term Outcomes 

Length of Stay

Robot = Laparoscopic

RCT: Low

Observational studies: 

High

Consistent Direct Imprecise Moderate

Complications (total)

Robot = Laparoscopic

RCT: Low

Observational studies: 

High

Consistent Direct Imprecise Moderate

Surgical Site Infection

Robot = Laparoscopic

RCT: Low

Observational studies: 

High

Consistent Direct Imprecise Moderate

Pain

Robot = Laparoscopic

RCT: Low

Observational studies: 

High

Inconsistent Direct Imprecise Low

Readmissions

Robot <Laparoscopic

Observational studies: 

High

Consistent Direct Imprecise Low

Long-term Outcomes

Incisional hernia

Single port robot > 

multiport 

laparoscopic

RCTs: Low 

Observational studies: 

High

Inconsistent Direct Imprecise Low
Robot-assisted Procedures in General Surgery Evidence Synthesis Program

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KEY QUESTION 2A – CHOLECYSTECTOMY: What is the costeffectiveness of robot-assisted surgery compared to conventional 

laparoscopic surgery for cholecystectomy?

Eighteen studies looked at robot-assisted cholecystectomy versus laparoscopic and included 

some measure of cost. There was 1 RCT.

13 Of the remaining 17, the majority were retrospective,

single institution, or single health system studies. There were 3 studies that used a national 

database49,56,58 and 1 study performed a budget impact analysis using existing published data.59

Studies were mixed with respect to procedures performed. Studies included a combination of 

traditional laparoscopic multi-port surgery, laparoscopic single-port surgery, robot-assisted 

multi-port surgery, and robot-assisted single-port surgery. Because most studies came from 

single institutions, sample sizes were generally small, with the majority of studies including 

fewer than 100 patients in the robot-assisted arm. 

Overall, 16 of 18 studies reported at least 1 measure of cost higher for the robot-assisted surgery

compared to the laparoscopic approach. The 1 RCT was a single institution study in Switzerland 

that evaluated 30 patients receiving single site robot-assisted surgery and compared them to 30 

patients receiving single site laparoscopic surgery for elective cholecystectomy.13 They found 

nearly a 50% higher cost for the robot driven by higher consumable costs, amortization, and 

overhead costs ("the cost of OR time").
Robot-assisted Procedures in General Surgery Evidence Synthesis Program

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Table 2. Evidence Table for Cholecystectomy Cost Studies 

Author, 

Year, 

Number

Study Design, 

Number of 

Institutions Comparison(s)

Number of 

surgeons

Sample 

Size Source of cost data Cost data

Misc. (Additional 

cost-pertinent 

outcomes and 

financial COI)

Bedeir

201660

Retrospective, 

single 

institution 

Robot-assisted

single site vs

traditional 

laparoscopic for 

elective outpatient 

cholecystectomy

1 (robot)

5 (lap)

46 robot

195 lap

"Cost data were obtained from 

financial department. Hospital 

cost in US dollars, not billed or 

hospital revenue. Cost divided 

into fixed and variable costs. 

Only variable costs are 

included. Fixed costs include 

salaries and hospital 

infrastructure. Fixed costs don’t 

differ between. procedures."

Total median variable 

cost: 1319 (robot) vs

1737 (lap), p<0.001

Provide OR time 

for robot but not for 

lap

One author had 

financial COI with 

Intuitive

Buzad

201333

Retrospective, 

single 

institution

Robot-assisted 

single incision vs

historical control of 

laparoscopic single 

incision 

cholecystectomies

1 20 robot

10 lap

"Cost based on instrument cost 

from preference cards; did not 

include purchase price or 

maintenance of robot. Sensitivity 

analysis performed for 

instrument costs: SILC estimates 

were average cost, based on 

number of cases, and a 

theoretical range for single port. 

Theoretical savings of no 

cholangiogram for robot was 

calculated." 

Preference card cost 

for instruments = 

$1268 (robot) vs

$1281 (lap); no pvalue as these are just 

single values for the 

preference card

**Excluded cost of 

using 5 "reusable" 

robotic instruments**

Operative times 84 

vs 85 min, p=NS

One author had 

financial COI with 

Intuitive

Farnsworth

201846

Retrospective, 

single 

institution

Abstract only

Robot-assisted vs

laparoscopic acute 

care surgery 

cholecystectomy

2 14 robot

37 lap

"day of surgery until discharge" Unadjusted OR costs: 

$3490 (robot) vs

$2190 (lap), p<0.001

Adjusted analysis 

found robot was $980 

more than lap BUT 

included OR time in 

analysis model

OR time 158 

(robot) vs 132 

(lap); P=NS

Financial COI not 

discussed
Robot-assisted Procedures in General Surgery Evidence Synthesis Program

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Author, 

Year, 

Number

Study Design, 

Number of 

Institutions Comparison(s)

Number of 

surgeons

Sample 

Size Source of cost data Cost data

Misc. (Additional 

cost-pertinent 

outcomes and 

financial COI)

Grochola

2019

13

RCT, single 

institution

Robot-assisted vs

laparoscopic single 

site elective 

cholecystectomy 

3 30 robot

30 lap

"Costs generated in the 

operating theatre include 

consumables needed for dVSSC 

and SILS (each patient), nonprocedure-specific surgical and 

anaesthesiologic consumables 

(costs per min), amortization of 

equipment and staff salaries 

(costs per minute). Ward costs 

divided into medical and nonmedical expenses as overhead 

per min.

Total cost (in Swiss 

Francs): 9743 (robot) 

vs 6900 (lap), p=0.001

Driven by: Higher 

consumables (2921 vs

882, p<0.001), 

amortization (932 vs

493, p=0.02), 

overhead costs in OR 

(1933 vs 1555, 

p=.017)

Total operative 

duration: 85.5 

(robot) vs 74 (lap), 

p=NS

Authors declared 

no conflicts

Gustafson, 

201636

Retrospective, 

single 

institution 

Robot-assisted

single-incision 

laparoscopic

cholecystectomy 

(RSILC) vs

traditional single 

incision laparoscopic 

cholecystectomy 

(TSILC)

1 38 robot 

44 lap

“Operative costs were obtained 

from the hospital database”

Variable direct supply 

cost ($1,967 robot vs 

$1,969 lap, p=0.99) 

Variable direct labor 

cost ($1,234 robot vs 

$1,122 lap, p=0.34). 

Fixed direct 

cost:$8,961 robot vs 

$5,379 lap, p<0.0001

Mean service item 

charges (not 

defined):$14,594 

robot vs $9,347 lap, 

p<0.0001). 

Total cost: $8,961.00 

robot vs $5,379.00 lap

OR time 98 robot 

vs 68 lap, 

p<0.0001

Authors declared 

no conflicts
Robot-assisted Procedures in General Surgery Evidence Synthesis Program

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Author, 

Year, 

Number

Study Design, 

Number of 

Institutions Comparison(s)

Number of 

surgeons

Sample 

Size Source of cost data Cost data

Misc. (Additional 

cost-pertinent 

outcomes and 

financial COI)

Hagen

201825

Retrospective, 

single 

institution

Robot-assisted

single site vs lap 

multi-port

Did not 

specify

99 robot

99 lap 

(matched 

analysis)

"Cost of the primary procedure 

was calculated including the 

capital investment and 

maintenance of robot with a flat 

fee per case as per hospital, 

instruments, and accessories per 

standardized OR procedure set, 

cost per OR-time of 17.3 USD 

per min in OR, and cost of 

hospitalization USD 627 for 

outpatients, and USD 1425 per 

day for inpatients as either 

previously established or per 

guidance of medical controlling 

department."

Total cost of index 

procedure $6158 

(robot) vs $4288 (lap), 

p<0.0001

In addition: cost of 

follow-up surgery was 

$695 (robot) vs $0 

(lap), p=0.02

Operative time: 97 

min (robot) vs 94 

min (lap), P=NS

Incisional hernia 

requiring surgery 

rate: 7% (robot) vs

0% (lap), p=0.014

Author financial 

COI with Intuitive

Hawasli, 

201655

Retrospective, 

single 

institution

Robot-assisted 

cholecystectomy 

(14/26 with single 

incision RC, all 

included in 1 

analysis) vs

laparoscopic 

cholecystectomy 

(26/220 with single 

incision LC, all 

included in 1 

analysis)

14 26 robot

220 lap 

No discussion of cost methods Mean direct cost: 

($2,704.08 RC vs 

$1,712.50 LC, 

p<0.0001) 

Gross median margin 

w/ no difference 

($1,726 LC vs $1,593 

RC) 

Mean case time 

RC: 121min vs LC: 

98.4min, p<0.001 

Mean OR time: 

RC: 86.6min vs 

LC: 63.9 min

Financial COI not 

discussed

Higgins

201661

Retrospective, 

single "health 

system"

Elective robotassisted vs

laparoscopic 

cholecystectomy

Did not 

specify

39 robot

343 lap

**See Footnote 1** Total supply cost: 

$1699 (robot) vs $631 

(lap), p<0.01

Case duration: 84 

min (robotic) vs 76 

min (lap), p=NS

Authors had no 

financial ties to 

Intuitive 
Robot-assisted Procedures in General Surgery Evidence Synthesis Program

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Author, 

Year, 

Number

Study Design, 

Number of 

Institutions Comparison(s)

Number of 

surgeons

Sample 

Size Source of cost data Cost data

Misc. (Additional 

cost-pertinent 

outcomes and 

financial COI)

Kaminski

201458

Retrospective, 

National 

Inpatient 

Sample (2010-

2011)

Robot-assisted vs

laparoscopic 

cholecystectomy for 

gallstone disease

Did not 

specify

524 + 1084 

(robot, 

2010/2011)

362,971 + 

370,958 

(lap, 

2010/2011)

"NIS data include total charges 

for individual hospitalizations. 

HCUP provides cost-to-charge 

ratios, to convert charges to 

estimated hospital costs. Costs 

calculated as product of total 

charges and cost-to-charge ratio. 

Hospital costs reflect money 

expended for patient care (not 

physician expenses). Indirect 

(non-medical) costs were not 

available. NIS data don’t allow 

calculating attributable costs."

Total costs: 

$21346 (robot) vs

$13829 (lap) in 2010, 

p<0.05

$18224 (robot) vs

$14181 (lap) in 2011, 

p<0.05

Authors declared 

no conflicts

Kane

202057

Retrospective, 

Single 

Institution

Robot-assisted vs

laparoscopic 

cholecystectomy

2 106 robot, 

1060 lap

"Financial data were obtained 

from the Institutional Clinical 

Data Repository; Inflation 

estimates of the Center for

Medicare and Medicaid Services 

Inpatient Prospective Payment

System were used to adjust cost 

to 2017 US dollars to account for 

medical-specific inflation."

Hospital cost: 

$6611 (robot) vs

$4930 (lap), p<0. 

0001

Total OR time 185 

min (robot) vs 160 

min (lap), p<0.001

Authors declared 

no conflicts

Khorgami

201949

Retrospective, 

National 

Inpatient 

Sample (2012-

2014)

Robot-assisted vs

laparoscopic 

cholecystectomy 

Did not 

specify

1271 robot

69,402 lap

"Hospital total charges were 

converted to cost estimates 

using hospital specific cost-tocharge ratios provided by HCUP. 

Average total cost of 

hospitalization was compared for 

the LS and RAS cohorts. 

Difference between average 

costs of laparoscopic vs robotic 

were calculated for each surgical 

subgroup."

$10,944 (robot) vs

$9618 (lap), 

"statistically 

significant", no pvalue provided

Authors declared 

no conflicts
Robot-assisted Procedures in General Surgery Evidence Synthesis Program

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Author, 

Year, 

Number

Study Design, 

Number of 

Institutions Comparison(s)

Number of 

surgeons

Sample 

Size Source of cost data Cost data

Misc. (Additional 

cost-pertinent 

outcomes and 

financial COI)

Lescouflair

201442

Retrospective, 

single 

institution 

Abstract only 

Robot-assisted

single incision 

laparoscopic 

cholecystectomy 

(RSILC) vs single 

incision laparoscopic 

cholecystectomy 

(SILC)

1 41 RSILC

41 SILC 

“Outcomes and cost were 

compared between the 2 

groups.”

“Secondary outcomes include 

duration of narcotic use, time to 

independent performance of 

daily activities and cost.” 

Cost: $3,673 SILC vs 

$7,518 RSILC, 

p=0.056 

OR time (min): 

RSILC 96.7 vs 

SILC 65.2 min, 

p<.00001 

Conflicts not 

reported 

Li, 201728| Retrospective, 

single 

institution

Single-site RC vs 

conventional LC 

(Number of ports not 

specified)

2 78 robot 

367 lap 

“Assessed data of total operation 

time, length of hospital stay, 

hospital charge, outpatient 

department (OPD) visits after 

discharge, and OPD service 

charges.” 

Results in New 

Taiwan Dollars: 

Average hospital 

charge: RC: 204,125 

vs LC: 49,218, 

p=0.001

Average OPD charge: 

RC: 836.6 vs 509.6, 

p=0.001 

OR time higher for 

RC (RC: 75.7min 

vs 

64.37min,p=0.035) 

Authors declared 

no conflicts

Morris

201459

Budget impact 

model for the 

UK NHS

Abstract only

Robot-assisted vs

laparoscopic 

cholecystectomy

NA NA "A model-based economic 

evaluation investigating cost of 

procedure accounting for 

operating staff, assistant time, 

theatre time, laparoscopic and 

robotic systems, instruments and 

LOS. Data from published 

sources."

Lap 2703 pounds vs

robot 2877-15,253 

pounds depending on 

service life and 

number of procedures 

per year

Conflicts not 

reported
Robot-assisted Procedures in General Surgery Evidence Synthesis Program

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Author, 

Year, 

Number

Study Design, 

Number of 

Institutions Comparison(s)

Number of 

surgeons

Sample 

Size Source of cost data Cost data

Misc. (Additional 

cost-pertinent 

outcomes and 

financial COI)

Newman

201662

Retrospective, 

single 

institution

Traditional lap vs

single site lap vs

single site robotassisted

Did not 

specify

39 robot

11 single 

lap

50 

traditional 

lap

**See Footnote 2** "Direct variable 

surgeon cost": 

traditional lap $929

Single incision lap 

$1407

Robotic $2608

(all comparisons 

p<0.05)

Exact values not 

provided for OR 

time, ~ 65-75 for 

traditional, ~ 75-

110 for single 

incision lap, ~ 90-

105 for robot

Authors declared 

no conflicts

Pokala

201956

Retrospective, 

Vizient national 

database

Lap vs robotassisted 

cholecystectomy for 

minor or moderate 

severity of illness

Did not 

specify

1,314 robot

53,028 lap

"Ratio of cost-to-charge (RCC) 

methodology is applied to 

estimate the cost of patient care 

along service lines"

Total cost: $8620 

(robot) vs $6503 (lap), 

p<0.001

LOS: 3.27 (robot) 

vs 3.1 (lap), 

p<0.001

One author had 

financial COI with 

a robotic surgical 

company

Rosemurgy, 

201450

Retrospective, 

single 

institution

Laparoscopic vs 

Robot-assisted 

Cholecystectomy 

(did not specify how 

many incisions)

Did not 

specify

31 robot 

201 lap 

“Through the Decision Support 

Team, ... Hospital Charges, 

Hospital Cost, Net Revenue, 

earnings before depreciation, 

interest, and taxes (EBDIT), and 

Net Income. Hospital Charges 

were the value requested for 

reimbursement. Hospital Cost 

was the value of money used to 

produce care described. Net 

Revenue defined as money 

received, regardless of cost of 

operation. EBDIT defined as Net 

Income before depreciation, 

interest, and income taxes. Net 

Income is value after Hospital 

Cost has been applied to Net 

Charges RC 

$33,238.42 vs LC 

$25,055.85, p<0.01

Net revenue: RC 

$9,121.49 vs LC 

$6,512.61, p = 0.29 

EBDIT: RC $6,196.07 

vs LC $3,507.86, 

p=0.26 

Net income: RC 

$5,848.59 vs LC 

$3,058.83, p=0.25

Operative duration: 

RC 140 vs Lap 93, 

p<0.01) 

No authors had 

financial ties to 

Intuitive 
Robot-assisted Procedures in General Surgery Evidence Synthesis Program

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Author, 

Year, 

Number

Study Design, 

Number of 

Institutions Comparison(s)

Number of 

surgeons

Sample 

Size Source of cost data Cost data

Misc. (Additional 

cost-pertinent 

outcomes and 

financial COI)

Revenue. Hospital Cost data 

were subdivided into variable 

costs, fixed costs, supply costs, 

drug costs, equipment costs, and 

facility costs. Fixed costs were 

defined as expenses that were 

not dependent on the level of 

care provided by the hospital. 

Facility Costs included basic 

Hospital Costs which cannot be 

traced to individual patient care 

and are, rather, allocated to all 

patients adjusted for severity of 

intervention and illness.

Variable costs : RC 

$1,714.30 vs LC 

$1,449.54, p=0.022 

Fixed costs: RC 

$1,826.90 vs 

$1,915.93, p=0.1665

Supply costs: RC 

$594.74 vs LC 

$636.65, p=0.4191 

Drug costs: RC 

$92.91 vs LC $76.93, 

p=0.5575

Equipment costs RC 

$336.96 vs LC 

$345.14, p=0.5076 

Facility costs: RC 

$22.60 vs LC $22.71, 

p=0.3099 

Total costs: RC 

$4,723.26 vs 

$4,578.88, p=0.7265 

Strosberg, 

201751

Retrospective, 

single 

institution

Robot-assisted vs

laparoscopic 

cholecystectomy 

(did not specify how 

many incisions)

1 97 lap 

(total)

140 robot 

(total)

35 lap (cost 

analysis)

“Cost data was obtained for each 

patient in the study group by our 

institution’s financial division. 

Variables including total charges, 

total payments, total direct cost, 

total indirect cost, and total 

overall cost were collected. 

Direct cost defined as the sum of 

Total charges: RC 

$33,120 vs $21,024, 

p<0.01

Total payments: RC 

$7,478 vs $5,887, 

p=0.34

Length of surgery 

longer for RC 

(74.5min vs 56min, 

p<0.01)
Robot-assisted Procedures in General Surgery Evidence Synthesis Program

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Author, 

Year, 

Number

Study Design, 

Number of 

Institutions Comparison(s)

Number of 

surgeons

Sample 

Size Source of cost data Cost data

Misc. (Additional 

cost-pertinent 

outcomes and 

financial COI)

68 robot 

(cost 

analysis)

*Patients 

that had 

IOC, 

conversion 

to open or 

did not 

have a 

payment 

were 

excluded 

from cost 

analysis

operative and hospital cost. 

Revenue was calculated as total 

payments minus total overall 

cost. Exclusion for cost analysis 

included cases with uncaptured 

operative and in-hospital 

payments, inpatient procedures, 

and cases with intraoperative 

cholangiogram or conversion to 

open.” 

Total direct cost: RC 

$4,692 vs $2,983, 

p<0.01 

Total indirect cost: RC 

($4,243 vs $2,801, 

p<0.01 

Total cost: RC $8,870 

vs $5,771, p<0.01 

Median revenue: RC -

848 vs 186, p<0.01

Footnote 1: "All data were obtained from the Surgical Profitability Compass Procedure Cost Manager System. Outcomes measured: LOS, case duration, and total supply 

cost. Total supply cost accounted for the cost of mesh. For robotic cases, total number and cost of robotic instruments were determined. Cost accounting for robotic 

instruments is determined by the purchase price of a particular instrument distributed equally among all the patients in whom the instrument was used." 

Footnote 2: "We developed mechanics that could identify the portion of procedure cost under control of the surgeon. This was defined as direct variable surgeon cost

(DVSC): surgical supply cost (drapes, gloves, etc); physician preference items; technology cost (per-use laparoscope cost, service contract amortized); and procedure time 

cost was variable cost of operating room use: 2.5 full-time equivalents per case minute. Proprietary robotic instruments are disposable after a pre-programmed number of 

uses, 5 or 10. Total cost of instrument divided by intended number of uses as each case cost: not corrected for actual number of uses.” 
Robot-assisted Procedures in General Surgery Evidence Synthesis Program

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Many of the studies had significant limitations, primarily related to the measurement of costs. 

Studies varied in terms of the detail provided as it relates to cost, with some providing no 

information at all. Others provided more specifics but only looked at 1 component of cost, such 

as disposable supply costs. Given the upfront cost of the robot, including the purchase price and 

ongoing maintenance costs, these cost assessments are incomplete. Studies also varied in their 

use of charges, payments, and costs, each of which will be more relevant to different parties. 

Charges, for example, are rarely paid by insurers and do not necessarily reflect the resources 

expended to care for the patient. Using cost-to-charge ratios to convert charges to costs is a blunt 

measure that is likely inaccurate, especially in surgery.11 Even among studies that focused on 

hospital costs, whether they included staff costs or indirect costs varied from 1 study to the next 

and these details were often not explicitly mentioned. As a result, cost estimates varied markedly 

across studies from as low as $1400 to as high as $33K. No study commented on updating costs 

based on inflation nor did they reference any type of recognized methodology when reporting 

cost information (eg, Second Panel on Cost Effectiveness, CHEERS).

Summary of Findings

While there are a number of studies comparing robot-assisted versus laparoscopic surgery for 

cholecystectomy, all had significant limitations, primarily surrounding the cost methodology

used (or lack of methodology). Nevertheless, there was an almost unanimous finding, including 

in randomized data, that the robot-assisted approach is more expensive than laparoscopic. 

Certainty of Evidence for Key Question 2A

Despite wide heterogeneous methodologic approaches to assessing cost in these studies and 

differing definitions of cost, nearly all found that robot-assisted approach for cholecystectomy 

was more expensive than laparoscopic. This directness and consistency support that that we have 

moderate certainty that robot-assisted is more expensive than laparoscopic cholecystectomy. 

How much more expensive is not known with precision. 

KEY QUESTION 1B – INGUINAL HERNIA SURGERY: What is the 

clinical effectiveness of robot-assisted surgery compared to 

conventional laparoscopic or open surgery for inguinal hernia repair?

We identified 23 publications that met inclusion criteria. There was 1 RCT, which was a US 

multi-institutional study of 102 patients assessing short-term outcomes between robot-assisted 

and laparoscopic unilateral inguinal hernia repair.

63 The remaining 22 studies were 

observational. Of these, 16 specified laterality in the patient demographics.64-79 4 studies reported 

on unilateral inguinal hernia only, 64,68,71,75 while 12 reported on both unilateral and bilateral.65-

67,69,70,72-74,76-79 The robot-assisted approach was compared to the laparoscopic approach in 18

studies.

12,64,65,68,70-83 Similarly, the open approach was compared to robot-assisted in 14

studies.

12,66-72,77,79,80,82-84 8 studies included primary and recurrent hernias.67,69,70,73-76,78 Of the 

remaining 14 studies, 5 reported only on primary hernias68,71,79,80,84 and the other 9 did not 

specify.12,64-66,72,77,81-83 Two studies were performed outside of the US.

72,73 Also, 3 studies 

reported outcomes from patients who were served at the Veterans Affairs hospital system.67,68,70

8 studies utilized prospectively maintained datasets.

64,68,,71,73,77,80,82,84 The studies varied in size 

from 55 to 75,981 patients. Propensity matching was performed in 5 studies.

12,66,69,77,83 Of note, 2 

studies published by the same group utilized overlapping patient samples,66,69 of which 1 study 
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only examines the outcomes for the subgroup of patients who are obese.66 Thus, only the study 

assessing the broader subset of patients is plotted in the subsequent figures.69

Intraoperative outcomes included OR time and rate of conversion from robot-assisted or 

laparoscopic surgery to open (Figure 5). Of the 8 studies included in this analysis, 5 compared 

robot versus laparoscopic approach, and 4 compared robot to open approach.65,67-69,73-75,78 With 2 

exceptions, all studies found that OR time was longer for the robot-assisted approach compared 

to either the laparoscopic approach or the open approach. One study reported similar increased 

OR time with unilateral laparoscopic robot-assisted inguinal hernia repair compared to robotassisted laparoscopic surgery.

67 However, there was no evidence of differences between the 2 

approaches for bilateral inguinal hernia repair. Another study assessed the learning curve of an 

experienced surgeon and found length of OR time decreased with experience and was not 

different at the end of the study.74 There was no evidence of differences in conversions between 

robot-assisted and laparoscopic approaches. 
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Figure 5. Inguinal Hernia Intraoperative Outcomes

Graphed is the point estimate and 95% confidence intervals for the difference in the indicated outcome between 

robot-assisted inguinal hernia repair and either laparoscopic (green) or open (gold) approaches. 
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Four postoperative short-term (≤30 days) outcomes were assessed for inguinal hernia repair: 

LOS, surgical site infections (SSI), readmissions, and total complications (Figure 6). Of the 5 

studies assessing outcomes for LOS,

65,69,75,77,78 2 studies demonstrated significantly decreased 

inpatient LOS for robot-assisted inguinal hernia repair compared to open approach,

69,77 and 1 of 

these studies77 demonstrated significantly decreased inpatient LOS for robot-assisted repair 

compared to laparoscopy as well. We elected to only graph the outpatient LOS in the 

corresponding figure, for which there was no difference among the 3 approaches, as this 

represents the more common disposition for this surgery. Two studies that looked at unilateral 

repairs did not show a difference between robot-assisted and laparoscopic approaches.

75,78 The 

final study reported outcomes for both unilateral and bilateral repairs, and they also found no 

difference in LOS for robot-assisted versus laparoscopic approach.65

Of the 7 studies assessing outcomes for SSI,

63,64,67-69,74,78 the RCT reported a trend to lower SSI 

rate when comparing robot-assisted to laparoscopic surgery,63 and 2 studies reported a trend to 

lower SSI rate in robot-assisted surgery compared to open,

67,69 but none of these studies met 

statistical significance (Figure 6). In contrast, 2 studies reported a non-significant trend to higher 

SSI rate in robot-assisted surgery compared to laparoscopic and open surgery.68,78 The 2 

remaining studies did not report a significant difference in SSI rates between robot-assisted 

versus laparoscopic approaches.

Five studies assessed outcomes for readmission following inguinal hernia repair.64,68,69,74,78 One

study that compared all 3 approaches for unilateral hernias found that readmission rates were 

lower for robot-assisted as compared to either laparoscopic or open approaches.68 The remaining

4 studies did not find a significant difference in readmission rates: 3 assessed robot versus 

laparoscopic repair (unilateral and a mix of laterality),

64,74,78 and 1 assessed robot versus open 

(for mix of laterality).69

Nine studies assessed outcomes for total complications.

63,64,67-69,71,73,74,78 Only 1 observational 

study found lower complication rates for the robot-assisted approach, which was seen in both the 

laparoscopic and open comparative arms.71 Of note, this study looked at only unilateral hernia 

repair. The remaining 10 studies, including the RCT, did not demonstrate significant differences 

in complications by approach: 6 studies assessed robot-assisted compared to laparoscopic 

approach (4 of which were on unilateral and 2 were mixed laterality)63,64,68,74,75,78 and 4 assessed 

robot-assisted to open repair (2 on unilateral hernias, 1 on bilateral hernias, and 3 on a mix of 

laterality67-69,73). 
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Figure 6. Inguinal Hernia Postoperative Short-term Outcomes

Figure 6 footnote: Only outpatient LOS was plotted for the LOS outcome. 

Graphed is the point estimate and 95% confidence intervals for the difference in the indicated outcome between 

robot-assisted inguinal hernia repair and either laparoscopic (green) or open (gold) approaches. 
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For long-term outcomes, 5 studies assessed inguinal hernia recurrence (Figure 7).64,67,68,71,80 One

study demonstrated lower recurrence rate for the robot-assisted approach as compared to both 

laparoscopic and open repair (for unilateral hernia repair).71 Two did not demonstrate a 

statistically significant difference that assessed both robot-assisted to laparoscopic and open 

comparative arms.68,80 Two additional studies also didn’t show differences in recurrence rates: 1 

assessed robot-assisted to laparoscopic comparing unilateral hernia repairs,

64 and another study 

comparing a mix of hernia laterality for robot to open repair.67
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Figure 7. Inguinal Hernia Postoperative Long-term Outcomes

Graphed is the point estimate and 95% confidence intervals for the difference in the indicated outcome between 

robot-assisted inguinal hernia repair and either laparoscopic (green) or open (gold) approaches.
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Six studies assessed postoperative pain following inguinal hernia repair (Figure 8).63-65,67,73,79 The 

RCT did not show a significant difference in pain outcomes for robot-assisted compared to 

laparoscopic inguinal hernia repair.63 One observational study reported worse pain for the robotassisted approach as compared to open repair for a mix of hernia laterality.

73 The remaining 

observational studies did not demonstrate a significant difference in pain among robot-assisted, 

laparoscopic, and open inguinal hernia repair for unilateral, bilateral, and mixed laterality repairs.
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Figure 8. Inguinal Hernia Postoperative Pain Outcomes

Graphed is the point estimate and 95% confidence intervals for the difference in the indicated outcome between 

robot-assisted inguinal hernia repair and either laparoscopic (green) or open (gold) approaches. 
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Summary of Findings

Operative room time was longer in patients treated with robot-assisted inguinal hernia repair 

compared to laparoscopic or open repair, particularly for unilateral hernia. There were no 

differences in conversions between robot-assisted and laparoscopic approaches. In terms of LOS, 

there may be a signal of a small benefit favoring the robot-assisted approach compared to open 

surgery for inpatient stays, but no difference for outpatient surgeries, which is the more common 

practice. There does not appear to be a signal of benefit with regard to SSI for the robot-assisted 

approach compared to laparoscopic or open surgery. There may be a small signal of benefit for 

lower readmissions with the robot-assisted approach for unilateral hernias. Regarding total shortterm postoperative complications and hernia recurrences, there is minimal to no benefit of the 

robot-assisted approach for inguinal hernia repair compared to the laparoscopic or open 

approaches. Most studies demonstrated no difference among approaches when assessing 

postoperative pain. 

Certainty of Evidence for Key Question 1B

Only 1 RCT was included in our analysis, for which there was greater certainty of evidence; 

however, it was judged as having moderate study limitation due to its single-blinded design with 

unclear allocation concealment and blinding of outcome assessment and potential for author bias. 

Due the observational nature of all remaining eligible studies, the study limitations were high 

and certainty of evidence was subsequently lower. We judged the certainty of evidence for the 

outcomes of longer OR time for robot-assisted inguinal hernia repair compared to laparoscopic 

and open inguinal hernia repair as low, primarily because data was imprecise. We judged the 

certainty of evidence that LOS for inpatient stays following robot-assisted surgery is shorter 

compared to open repair and no difference in outpatient LOS as moderate. Evidence that LOS for 

robot-assisted was not different compared to laparoscopic repair was determined to be moderate. 

We judged the certainty of evidence that SSI rates following robot-assisted surgery were not 

different as compared to laparoscopic and open repair as low due to inconsistency and 

imprecision of the data. We deemed certainty of evidence that readmissions following robotassisted surgery were similar to the other 2 approaches as low based on inconsistency in the data. 

The evidence of no difference in major complications and recurrences among the surgical 

techniques was assessed as very low due to inconsistency and imprecision of the data. The 

certainty of evidence that there is no difference in postoperative pain among the 3 approaches 

was judged as low due to inconsistency and imprecision.

Table 3. Certainty of Evidence for Inguinal Hernia Repair Studies

Outcome Study Limitations Consistency Directness Precision

Certainty of 

Evidence

Intraoperative

Operating Room Time

Robot > 

Open/Laparoscopic

Observational studies: High Consistent Direct Imprecise Moderate

Postoperative Short-Term Outcomes

Length of Stay 

Robot < Open 

(inpatient)

Observational studies: High

Consistent

Consistent

Direct

Direct

Precise

Precise

Moderate 

Moderate 
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Outcome Study Limitations Consistency Directness Precision

Certainty of 

Evidence

Robot = Open 

(outpatient)

Robot = Laparoscopic

Consistent Direct Precise Moderate

Surgical Site Infection

Robot = Open/ 

Laparoscopic

RCT: Moderate

Observational studies: High

Inconsistent Direct Imprecise Low

Readmissions

Robot = Open/ 

Laparoscopic

Observational studies: High Consistent Direct Imprecise Low

Total complications

Robot = Open/ 

Laparoscopic

RCT: Moderate

Observational studies: High

Inconsistent Direct Imprecise Low

Postoperative Long-Term Outcomes

Hernia Recurrence

Robot = Open/ 

Laparoscopic

Observational studies: High Consistent Direct Imprecise Very Low

Pain

Robot = Open/ 

Laparoscopic

RCT: Moderate

Observational studies: High

Inconsistent Direct Imprecise Low

KEY QUESTION 2B – INGUINAL HERNIA SURGERY: What is the costeffectiveness of robot-assisted surgery compared to conventional 

laparoscopic or open surgery for inguinal hernia repair?

There were 5 studies that reported cost information for inguinal hernia repairs. There was 1 

RCT.63 Of the remaining 4 studies, 3 were single-institution retrospective reviews65,68,78 and the 

last was a retrospective review of a national database.77 The 1 randomized trial compared robotassisted and laparoscopic transabdominal hernia repairs at 6 institutions in the United States. 

They limited inclusion to only surgeons who had performed at least 25 prior robot-assisted and 

laparoscopic procedures. With respect to cost, they found the robot-assisted approach had over 

twice the hospital cost of the laparoscopic approach ($3,258 vs $1,421). They did not include 

capital equipment costs in their analysis.

Three of the 4 remaining studies also found the cost of the robot-assisted approach to be higher 

than the cost of the laparoscopic approach. Details regarding what went into cost estimates were 

generally limited. One study did not mention any information aside from “financial data were 

obtained from the institutional Clinical Data Repository.” The 1 study that did not find a cost 

difference excluded a large component of robot-assisted costs (purchase price of equipment and 

annual contract),

2

 likely accounting for their null findings. None of the studies comment on how 

they accounted for staff/labor costs, which are the largest component of OR costs.10 This point is 

important as all 4 that reported operative time found operative time to be longer in the robotassisted arm compared to the comparison arms. None of the studies reference a recognized 

methodology when reporting cost information (eg, Second Panel on Cost Effectiveness, 

CHEERS).
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Table 4. Evidence Table for Inguinal Hernia Cost Studies

Author, 

Year, 

Number

Study 

Design, 

Number of 

Institutions

Comparison(s) Number 

of 

surgeons 

Sample 

Size

Source of cost 

data 

Cost data Misc.

outcomes

Charles, 

201768

Retrospective 

review, single 

institution

Robot-assisted

vs lap vs open 

primary 

unilateral 

inguinal hernias

10 69 robot

241 lap

191 open

"Financial data 

were obtained 

from the 

institutional 

Clinical Data 

Repository."

Hospital 

cost: Robot 

$7162, lap 

$4527, open 

$4264 

(p<0.001)

OR time 

longer for 

robotic 

surgery (105 

min robot, 

81 min lap, 

71 min

open; 

p<0.001)

No 

difference 

discharge 

home same 

day 

Janjua

202077

Retrospective, 

HCUP-State 

Inpatient 

Databases & 

AHA data 

from 8 states 

(2009-2015)

Robot-assisted

vs lap vs open 

inguinal hernia

repairs for 

inpatients

Not 

stated

2960 

(open), 

2960 

(lap), 

1480 

(robot); 

propensity 

matched

"HCUP-provided

cost-to-charge 

ratios were used 

to calculate cost 

by multiplying 

total charges with 

cost-to-charge 

ratio. For dataset 

containing

cost, years 2011 

- 2014 for Iowa 

were dropped 

because no cost 

data was 

available."

$18,494 

(robot) vs

$14,738 

(lap) vs

$16,740 

(open); 

p<0.0001 for 

robot vs

open and 

lap 

comparisons

LOS: 5.0 

(open), 3.6 

(lap), 2.2 

(robot); 

p<0.0001 for 

robot vs

open and 

lap 

comparisons

Khoraki

201978

Retrospective, 

single 

institution

Robot-assisted

vs lap inguinal 

hernia repair

4 45 (robot) 

138 (lap)

See footnote 1 Total 

hospital 

cost: $9994 

(robot) vs

$5995 (lap), 

p<0.01

Operative 

time: 116 

min (robotic) 

vs 95 in 

(lap), p<0.01

Prabhu

202063

Multiinstitutional 

RCT

Robot-assisted

vs lap TAPP

Not 

stated

54 lap

48 robot

Costs per case at 

each institution 

were reported

as total cost, 

operating room 

cost (cost per min 

OR time per 

case), and 

disposable/

reusable cost, 

include 

disposable

Total cost 

$3258 

(robot) vs

$1421 (lap); 

p<0.001

Operative 

time (skin to 

skin) 75.5 

min (robot) 

vs 40.5 min 

(lap), 

p<0.001
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materials and 

reusable 

materials - 

robotic 

instruments. 

Robotic and 

laparoscopic 

capital equipment 

cost were not 

amortized.

Waite, 

201565

Retrospective, 

single 

institution 

Robot-assisted

vs laparoscopic 

TAPP repair

Not 

stated

24 lap

39 robotic

"institution 

financial 

department... 

included direct 

costs, facility net 

revenue, and 

contribution 

margin"

Direct costs were 

variable costs of 

surgery (ie, 

mesh, disposable 

lap equipment, 

reposable robotic 

equipment).

Capital costs (ie,

robotic system, 

lap towers, and 

non-disposable 

equipment) NOT

included. 

Average 

direct cost 

per case 

was $3216 

(lap) vs

$3479 

(robot), 

p=NS

Operative 

time was 

longer 

robotic (77.5 

minutes vs

60.7 

minutes, 

p=0.001)

Footnote 1: 3 separate cost analyses were performed: 1. Total hospital costs: estimated cost of anesthesia, operating 

room, and recovery in addition to the disposable supplies and medications used during surgery. A combination of 

case-level and time-based system (per 1/2 h increment) used to calculate cost of surgery. Case-level is determined 

by ASA, procedure complexity, and equipment and staff. 2. Total disposable supplies and categories costs: 

combined operating room usage with supply pricing. Each surgery had its disposable supplies usage queried. 

Amount and costs for trocars, fixation devices, meshes, medications, drapes, and all accessories and other disposable 

equipment were collected. Cost adjusted to 2017 dollars. 3. Capital and service cost of the Robotic da Vinci® 

Surgical Systems: actual cost of systems was obtained and its depreciation was calculated based on an estimated 6-

year lifespan. Capital cost associated with utilizing the robot per case was calculated as total depreciation during the 

study period divided by number all robotic cases performed by all surgeons. Cost of maintenance services per case 

was added.

Summary of Findings

Five studies compared the costs of robot-assisted as compared to laparoscopic or open surgery 

for inguinal hernia repair. While there were significant limitations with the methodology, there is 

a consistent finding, including from randomized data, that the robot-assisted approach is more 

expensive than the laparoscopic and the open approach. How much more expensive is not known 

with precision. However, the lack of cost-effectiveness studies suggests that weighing the 

balance between the added cost against possible benefits and risks of the robot-assisted approach 

are not known. 
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Certainty of Evidence for Key Question 2B

Based on directness and consistency in the evidence, including from randomized data, we have 

moderate certainty that robot-assisted surgery is more expensive than laparoscopic or open 

surgery for inguinal hernia repair. As there were no formal cost-effectiveness analysis, no 

conclusion can be made in that regard. 

KEY QUESTION 1C – VENTRAL HERNIA SURGERY: What is the 

clinical effectiveness of robot-assisted surgery compared to 

conventional laparoscopic or open surgery for ventral hernia repair?

We identified 21 publications that met the inclusion criteria for assessing clinical outcomes. 

There was only 1 RCT, which was a conference abstract comparing robot-assisted to 

laparoscopic ventral hernia repair.85 The remaining 20 studies were observational studies, of 

which 7 studies compared robot-assisted ventral hernia repair to open repair only,

86-92 11 studies 

compared robot-assisted surgery to laparoscopic surgery only,76,93-102 and 2 studies compared 

robot-assisted surgery to both laparoscopic and open approaches.103,104 Six studies included 

analysis of patients who underwent transversus abdominis release as a component of the ventral 

hernia repair.86-88,90,92,101 The only RCT was a single institutional study from Brazil and included 

38 subjects.

85 All of the observational studies were done in the United States; of these, only 4 

were specified to be multi-institutional,

87,90,96,97 while 9 were specified to be from a single 

institution.

76,86,88,92,93,95,100-102 Eleven of the observational studies utilized retrospective data from 

prospectively maintained databases.

89-92,94,96,98,99,101,103,104 The studies varied in size from 25 to

46,799 subjects. Of the observational studies, 7 studies utilized matching of various preoperative 

patient or hernia characteristics in their outcome analysis.87,89,90,96,97,99,103

The RCT warrants specific mention.85 It was very limited in terms of the data the authors 

presented and was only an abstract. The sample sizes were quite small, 19 in each arm. The study 

compared robot-assisted ventral hernia to laparoscopic, but other details of the operative 

techniques were not provided. They did not report on our intraoperative outcomes of interest 

(OR time, intraoperative complications, transfusions, or conversion to open surgery) or the 

majority of our postoperative short-term outcomes (LOS, complications, SSI, or readmissions). 

They did report (without actual supporting data) that “QOL before and after the procedures 

showed improvement in both groups and but in favor of the robot-assisted group as well as the 

gain in the abdominal wall function.” They reported lower recurrence rate for robot group, 

10.5% (2/19) as compared to 21.1% (4/19) at 1 year. One death was reported in the laparoscopic 

group. They did not comment on any deaths in the robot-assisted group. Therefore, this RCT was 

not abstracted along with the observational data analyzed below.

Figure 9 presents results for 4 intraoperative outcomes: OR time, intraoperative complications, 

transfusions, and conversion to open surgery. Fourteen observational studies were included in 

this subset of analysis.

76,86-88,90-93,95-97,100,101,103 One study compares robot-assisted surgery to both 

laparoscopic and open approaches,103 while 7 studies only compare to laparoscopic,76,93,95-

97,100,101 and 6 studies only compare to open surgery.

86-88,90-92 Four studies87,90,96,103 utilize 

preoperative patient characteristics for matching, while the remaining 8 do not utilize matching.

Of the 11 studies assessing OR time, all studies demonstrate a statistically significant increase 

with robot-assisted ventral hernia repair compared to open and laparoscopic approaches,

76,86-
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88,93,95,97,100,101,103 with the exception of 1 study that demonstrated no difference comparing robot 

to open repair.92 Of the 7 studies assessing intraoperative complications,86,87,90,91,96,101,103 2 

unmatched studies demonstrate a significantly decreased complication rate with robot-assisted 

ventral hernia repair compared to laparoscopic and open repairs,86,101 and the remaining 

unmatched study demonstrated no difference in complication rate between robot-assisted and 

open repair.91 The 4 matched studies do not demonstrate a significant difference in complication 

rate among the approaches.87,90,96,103 Two matched studies were included in the analysis for 

transfusion,96,103 of which 1 study demonstrated a significant decrease in transfusions in robotassisted ventral hernia repair compared to both open and laparoscopic approaches,103 while the 

other study did not demonstrate a difference between robot-assisted and laparoscopic surgeries.96

Of the 6 studies included in the analysis for conversion,86,90,92,95,101,103 1 matched103 and 1 

unmatched101 study each demonstrated a decreased conversion rate to open surgery with robotassisted surgery compared to laparoscopy, while a third study95 favored decreased conversion 

rates with robot-assisted surgery but was not significant. Of the 4 studies assessing robot-assisted

conversion rates when compared to open ventral hernia repair, 1 matched study showed a 

significantly increased conversion rate of robot-assisted surgery,90 while another matched study 

demonstrated a non-significant increase in conversion.103 Of the remaining 2 unmatched studies,

1 showed a non-significant increase in conversion from robot-assisted surgery to open,92 while 

there was no difference in the remaining study.86
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Figure 9. Ventral Hernia Intraoperative Outcomes

Graphed is the point estimate and 95% confidence intervals for the difference in the indicated outcome between 

robot-assisted ventral hernia repair and either laparoscopic (green) or open (gold) approaches. Studies utilizing 

matching (circles) are listed in the left-hand side, while studies that did not utilize matching (squares) are listed on 

the right-hand side.
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Figure 10 presents the results for 5 postoperative short-term outcomes: LOS, complications, 

surgical site infection (SSI), readmissions, and mortality. Nineteen observational studies were 

included in this subset of analysis.

76,86-88,90-104 Two studies compared robot-assisted surgery to 

both open and laparoscopic approaches,103,104 11 studies compared to only laparoscopy,76,93-102

and 6 studies compared to only open surgery.86-88,90-92 Five studies87,90,96,99,103 utilized matching 

while the remaining 14 did not.

Of the 18 studies assessing outcomes for LOS,76,86,87,90-104 6 studies comparing the robot-assisted 

to laparoscopic approaches,

76,96,99,101,102,104 of which 2 were matched,99,105 demonstrated a 

significantly lower LOS for the robot-assisted arm. All 7 studies comparing robot-assisted

ventral hernia repair to the open approach,86,87,90-92,103,104 of which 3 were matched,87,90,103 also 

demonstrated a significantly lower LOS. Within the matched cohort, only the laparoscopic 

comparison arm of 1 study demonstrated no difference in LOS.103 In contrast, 1 unmatched study 

demonstrated a small but statistically significant increase in LOS with robot-assisted surgery 

compared to laparoscopy.

97 However, the remaining 5 studies did not demonstrate a significant 

difference.93-95,98,100

Of the 13 studies assessing outcomes for complications,87,90,92,93,95-101,103,104 4 matched studies

revealed a significantly lower rate of postoperative complications of robot-assisted ventral hernia 

repair compared to both laparoscopic and open approaches,

87,96,99,103 and 1 unmatched study 

demonstrated a lower robot-assisted complication rate compared to laparoscopy.

93 Only 1 

matched study demonstrated a non-significant trend toward lower complication rates in the 

robot-assisted arm compared to open surgery.90 In 1 unmatched study, robot-assisted ventral 

hernia repair demonstrated a slight but significant decrease in complication rate compared to the 

open approach, while within the same study, the robot-assisted surgery demonstrated a similarly 

slight but significant increase in complications when compared to laparoscopy.

104 The remaining

6 studies demonstrated no difference in complication rate in robot-assisted ventral hernia repair 

compared to laparoscopy or open surgery.

86,92,95,98,100,101

Of the 9 studies examining the outcome of SSI,86,87,91,95-97,100,101,103 only 1 matched study87

demonstrated a significantly lower SSI rate with robot-assisted surgery compared to open repair. 

In a matched study comparing robot-assisted ventral hernia repair to both open and laparoscopic 

approaches, there was a trend toward lower SSI with robot-assisted surgery when compared to 

open surgery, but there was no difference when compared to laparoscopic repair.103 The 

remaining 7 studies did not demonstrate a significant difference among the approaches in SSI 

rates.

86,91,95-97,100,101

Of the 11 studies assessing outcomes for readmissions,86-88,90-93,96,99,101,104 1 unmatched study

demonstrated significant decrease in readmission rate following robot-assisted ventral hernia 

repair compared to open.92 Two other unmatched studies demonstrated non-significant decreases

in readmission following robot-assisted surgery compared to open.

88,91 The remaining 4 studies

comparing robot-assisted to open surgery86,87,90,104 including 2 matched studies,87,90 demonstrated 

no difference. There was no difference in readmission rate in the 5 studies comparing robotassisted ventral hernia repair to laparoscopy,93,96,99,101,104 of which 2 were matched.96,99

Of the 8 studies assessing mortality, the data was overall mixed with none of the studies 

demonstrating significantly different mortality rates among the approaches.86,87,90,95,96,98,101,104
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While 1 matched90 and 1 unmatched104 study demonstrate non-significant trends toward 

decreased mortality rates with the robot-assisted approach when compared to open surgery, 

another pair of matched87 and unmatched86 studies showed no difference in mortality between 

these approaches. When comparing robot-assisted ventral hernia repair with the laparoscopic 

approach, 2 studies,96,104 of which 1 was matched,96 had a trend toward increased mortality with 

robot, while 1 unmatched study101 trended toward decreased mortality with robot, and the 

remaining 2 unmatched studies demonstrated no difference between these approaches.95,98
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Figure 10. Ventral Hernia Postoperative Short-term Outcomes

Graphed is the point estimate and 95% confidence intervals for the difference in the indicated outcome between 

robot-assisted ventral hernia repair and either laparoscopic (green) or open (gold) approaches. Studies utilizing 

propensity matching (circles) are listed in the left-hand side, while studies that did not utilize propensity matching 

(squares) are listed on the right-hand side.
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Figure 11 presents the results for ventral hernia recurrence, the only postoperative long-term 

outcome for ventral hernia repair. Of the 7 studies included in this analysis,89,91,93,95-97,106 5 

studies compared robot-assisted surgery to the laparoscopic approach,76,93,95-97 while 2 studies89,91

compared the robot-assisted approach to the open approach. Only 1 matched study demonstrated 

a slight but significantly decreased recurrence rate following robot-assisted ventral hernia repair 

compared to laparoscopic repair,96 while the other matched study97 and 3 unmatched 

studies76,95,97 demonstrated a trend toward decreased hernia recurrence compared to laparoscopic 

repair without significance. The 2 studies comparing robot-assisted to open approaches revealed 

a non-significant trend toward increased recurrence rate.

89,91

Figure 12 presents the results for postoperative pain following ventral hernia repair. Only 3 

studies were included in this analysis,96,101,102 which all compared robot-assisted surgery to 

laparoscopic repair. The matched study demonstrated no difference between the approaches,96

while 1 unmatched study demonstrated a significant decrease in pain following robot-assisted

ventral hernia repair,102 and the remaining unmatched study favored the robot-assisted approach 

without significance.101
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Figure 11. Ventral Hernia Postoperative Long-term Outcomes

Graphed is the point estimate and 95% confidence intervals for the difference in the indicated outcome between 

robot-assisted ventral hernia repair and either laparoscopic (green) or open (gold) approaches. Studies utilizing 

matching (circles) are listed in the left-hand side, while studies that did not utilize matching (squares) are listed on 

the right-hand side.
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Figure 12. Ventral Hernia Postoperative Pain Outcomes

Graphed is the point estimate and 95% confidence intervals for the difference in the indicated outcome between 

robot-assisted ventral hernia repair and laparoscopic (green) approaches. Studies utilizing matching (circles) are 

listed in the left-hand side, while studies that did not utilize matching (squares) are listed on the right-hand side.
Robot-assisted Procedures in General Surgery Evidence Synthesis Program

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Summary of Findings

Operative room time was significantly longer in robot-assisted ventral hernia repair compared to 

both the laparoscopic and open approaches in all but 1 study included. There was no evidence of 

a difference in intraoperative complication rate among the 3 approaches. There is a possible 

trend toward decreased transfusion rate with robot-assisted surgery compared to laparoscopic 

and open repairs, with 1 matched study demonstrating a significant difference favoring robotassisted surgery and another demonstrating no difference. With regard to conversion to open 

surgery, most studies demonstrate a decreased rate of conversion with robot-assisted surgery 

compared to the laparoscopic approach. Robot-assisted ventral hernia repair appears to have 

significantly decreased LOS compared to open repair; however, this decrease may be less 

significant when compared to laparoscopic repair. There is a likely decrease in postoperative 

complication rate following robot-assisted repair compared to both laparoscopic and open 

approaches based on the results of matched studies (unmatched studies do not support this trend). 

There may be a small signal favoring robot-assisted ventral hernia repair for reducing

postoperative SSIs compared to open surgery; however, there does not appear to be evidence of a 

difference when compared to the laparoscopic approach. There is no evidence of a difference in 

readmission or mortality rates among the approaches. In terms of hernia recurrence, the 2 studies

comparing robot-assisted ventral hernia repair to open surgery demonstrated no difference, while 

there may be a slight trend favoring robot-assisted ventral hernia repair compared to laparoscopic 

surgery based on results from 1 matched study. Finally, there may be a small signal of decreased 

postoperative pain favoring the robot-assisted approach when compared to the laparoscopic 

approach based on significant findings from 1 unmatched study. However, the matched study 

does not support this. 

Certainty of Evidence for Key Question 1C 

All studies included in this analysis were observational studies, which decreased the overall 

certainty of evidence. The 1 available RCT was too limited in detail to use in our analysis. We 

judged the certainty of evidence for the outcome of increased OR time for robot-assisted ventral 

hernia repair compared to open and laparoscopic repairs as high due to the consistency among 

nearly all studies included in this analysis, except for 1 unmatched study. We judged the 

certainty of evidence that there is no difference in intraoperative complications among the 

approaches as low due to inconsistency and imprecision. We judged the certainty of evidence 

that there is the same or slightly decreased rate of transfusion for robot-assisted surgery 

compared to open and laparoscopic hernia repairs as low because the few matched studies that 

assessed this particular outcome were inconsistent and imprecise. We judged the certainty of 

evidence that there is a decreased conversion rate to open surgery with robot-assisted surgery 

compared to laparoscopic surgery as low, as the data was consistent but imprecise. We judged 

the certainty of evidence that robot-assisted ventral hernia repair decreased LOS compared to 

open surgery and less significantly when compared to laparoscopic surgery as moderate, based 

on preciseness and consistency across matched and unmatched studies. Both outcomes of 

postoperative complications and SSI were deemed to have low certainty of evidence due to the 

inconsistency and imprecision of the data. Mortality and readmissions were judged to be 

equivalent across the 3 approaches with moderate certainty of evidence. There is low certainty 

that there may be a minimal difference in hernia recurrence favoring robot-assisted ventral hernia 

repair compared to laparoscopy and no difference compared to open surgery. Finally, there is a 
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low certainty that there is no difference in postoperative pain following ventral hernia repair in 

the 3 approaches, based on only 2 studies.

Table 5. Certainty of Evidence for Ventral Hernia Repair Studies

Outcome Study Limitations Consistency Directness Precision

Certainty of 

Evidence

Intra-operative

Operating Room 

Time

Robot > Open/ 

Laparoscopy

Unmatched observational 

studies: High

Matched observational 

studies: Moderate

Consistent Direct Precise High

Intraoperative 

Complications

Robot = Open/ 

Laparoscopy

Unmatched observational 

studies: High

Matched observational 

studies: Moderate

Inconsistent Direct Imprecise Low

Transfusion

Robot < Open/ 

Laparoscopy

Matched observational 

studies: Moderate

Inconsistent Direct Imprecise Low

Conversion to Open 

Surgery

Robot < Laparoscopy

Robot > Open

Unmatched observational 

studies: High

Matched observational 

studies: Moderate

Consistent

Consistent

Direct

Direct

Imprecise

Imprecise

Low

Low

Postoperative Short-term

Length of Stay

Robot < Open/ 

Laparoscopy

Unmatched observational 

studies: High

Matched observational 

studies: Moderate

Consistent Direct Precise Moderate

Postoperative 

Complications

Robot < Open/ 

Laparoscopy

Unmatched observational 

studies: High

Matched observational 

studies: Moderate

Inconsistent Direct Imprecise Low

Surgical Site 

Infection 

Robot < Open

Robot = Laparoscopy

Unmatched observational 

studies: High

Matched observational 

studies: Moderate

Inconsistent

Inconsistent

Direct

Direct

Imprecise

Imprecise

Low

Low

Readmissions

Robot = Open/ 

Laparoscopy

Unmatched observational 

studies: High

Matched observational 

studies: Moderate

Consistent Direct Imprecise Moderate

Mortality

Robot = Open/ 

Laparoscopy

Unmatched observational 

studies: High

Matched observational 

studies: Moderate

Consistent Direct Imprecise Moderate

Postoperative Long-term

Hernia Recurrence

Robot = Open/ 

Laparoscopy

Unmatched observational 

studies: High

Matched observational 

studies: Moderate

Consistent Direct Imprecise Low

Pain

Pain

Robot < Laparoscopy

Unmatched observational 

studies: High

Consistent Direct Imprecise Low
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Outcome Study Limitations Consistency Directness Precision

Certainty of 

Evidence

Matched observational 

studies: Moderate

KEY QUESTION 2C – VENTRAL HERNIA SURGERY: what is the costeffectiveness of robot-assisted surgery compared to conventional 

laparoscopic or open surgery for ventral hernia repair? 

We identified 6 studies that compared robot-assisted ventral hernia to other approaches and 

provided some data on costs. Two were single institution studies,103,107 2 used the National 

Inpatient Sample,94,98 1 used the Vizient administrative database,104 and 1 used a surgical 

registry.101 One study reported only cost data and no clinical outcomes.107 All compared robotassisted to laparoscopic surgery, with 2 also including an open comparison. Three studies found 

the robot approach to be more expensive than laparoscopic surgery, 1 found the robot-assisted

approach had a non-statistically significant higher cost than laparoscopy, and 2 found the robotassisted surgery and laparoscopy were similar with respect to costs. 

As with inguinal hernia, the methodology of the included studies was very limited, especially as 

it relates to details regarding how costs were derived. Evidence of the diversity of methods used 

is the fact that cost estimates ranged from as low as $4,000 to as high as $61,000 for the cost of 

the robot. This reflects the fact that when measuring costs, investigators must be very specific 

about the perspective (cost vs charge), time frame (just OR, OR and hospital stay, hospital stay + 

30/90 days), and explicit details about what is and is not included in cost estimates (direct vs 

indirect, variable vs fixed, etc). None of the studies included all of these details. Most studies 

provided less than 1 sentence about how cost estimates were derived. Several studies relied on 

administrative databases and used cost-to-charge ratios to estimate hospital costs. Previous 

research has demonstrated that these measures are prone to bias, especially in surgery.

11,108 It is 

unlikely that these methods adequately capture the nuance of cost intrinsic to the robot, such as 

the amortization of the purchase price, the service contract, and the semi-variable cost of the 

surgical instruments. As with the inguinal hernia studies, none of these studies comment on staff 

costs nor did they follow reporting guidelines (eg, Second Panel on Cost Effectiveness, 

CHEERS). Two of the included studies did find the operative time was longer for the robotassisted approach compared to the laparoscopic approach, with 1 study finding the operative 

times of robot-assisted cases were approximately double those of the laparoscopic cases (240 

minutes versus 120 minutes). When dealing with large differences in time, consideration must be 

given to staffing costs and, perhaps more importantly, the opportunity cost of not performed 

cases. 
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Table 6. Evidence Table for Ventral Hernia Cost Studies

Author, 

Year, 

Number

Study 

Design, 

Number of 

Institutions

Comparison Number 

of 

surgeons 

Sample 

Size

Source of cost 

data 

Cost data Misc.

outcomes

Armijo, 

2018104

Retrospective 

review of 

Vizient 

database

Robotassisted vs

laparoscopic 

vs open 

ventral 

hernia repair

Not stated 39,505 

open

6,829 lap

465 robotic

"Ratio of cost-tocharge method 

applied for 

estimating cost 

of patient care..."

Total direct 

cost: $9000 

(open), $7000 

(lap), $10,000 

(robot)

Median 

LOS was 5 

days 

(open), 3 

days (lap), 2 

days (robot)

Coakley, 

201798

Retrospective 

review of 

National 

Inpatient 

Sample 

(2008-2013)

Robotassisted vs

laparoscopic 

ventral 

hernia repair

Not stated 351 robotic

32,243 lap

"Total hospital 

charges..."

Adjusted 

model 

(controlling for 

CCI, 

geographic, 

public vs

private etc) 

mean charges 

were $41,911 

(lap) vs

$61,205 

(robot)

LOS no 

different lap 

vs robot 

(3.4 days 

lap, 3.5 

days robot, 

p=NS)

Khorgami

, 201994

Retrospective 

review of 

National 

Inpatient 

Sample 

(2012-2014)

Robotassisted vs

laparoscopic 

ventral 

hernia repair

Not stated 3600 lap

99 robotic

"Hospital total 

charges were 

converted to cost 

estimates using 

hospital specific 

cost-to-charge 

ratios provided 

by HCUP. 

Admissions with 

total charges 

below 0.1 

percentile or 

above 99.9 

percentile were 

considered 

outliers and 

excluded from 

analysis." 

$10,739 (lap) 

vs $13,441 

(robotic); pvalue not 

provided

LOS 2.7 

days (lap) 

vs 2.9 days 

(robot); pvalue not 

provided

Song, 

2017103

Retrospective 

review, 

Premier 

Perspectives 

Database, 

Abstract only

Robotassisted vs

lap vs open 

elective 

ventral 

hernia 

repairs in 

patients with 

BMI > 30

Not stated 2 samples 

(depending 

on 

comparison

)... 94/94 

robot vs lap 

and 96/96 

robot vs 

open 

"total cost 

included direct 

cost and 

overhead cost 

and was 

adjusted for 

inflation to 2015 

US dollars"

All were the 

same... 

approximately 

$10,500 

(p=NS)

OR time 

was 231 

min (robot), 

169 min 

(lap), and 

163 min 

(open)... 

robot and 

lap (<.0001)

LOS was 

3.1 days 

(robot), 3.2 
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days (lap), 

5.3 days 

(open); 

robot vs

open 

(p=0.003)

Tan, 

2017107

Retrospective 

review, single 

institution, 

Abstract only

Robotassisted vs

laparoscopic 

ventral 

hernia 

repairs

1 46 robotic

47 lap

Primary 

outcome: 

"disposable 

operating room 

costs" 

Secondary 

outcomes: 

"technical direct 

costs such as 

costs from the 

laboratory or 

pharmacy..."

Median total 

variable costs 

were $4,551 

(lap) versus 

$4362 (robot), 

p=NS; OR 

median costs 

were $3,391 

(lap) versus 

$3,095 (robot), 

p=NS

Results 

state no 

difference in 

OR time or 

LOS but no 

data

Warren, 

2017101

Retrospective 

review, 

Americas 

Hernia Society 

Quality 

Collaborative 

(multiinstitutional)

Robotassisted vs

laparoscopic 

ventral 

hernia repair

Not stated 103 lap

53 robotic

No details 

provided

Mean direct 

hospital cost 

$13,943 (lap) 

vs $19,532 

(robotic), 

P=NS

Operative 

time 121 

min (lap) vs

245 min 

(robotic), 

p<0.001

Summary of Findings

There are only a handful of cases comparing the costs of robot-assisted versus laparoscopic or 

open surgery for ventral hernia repair. All had significant limitations, primarily surrounding the 

cost methodology used. However, 4 of the 6 studies reported that the robot-assisted approach 

was more expensive than either the laparoscopic or open approach (with large effect size) and 

the other 2 studies reported no difference in cost as compared to laparoscopic repair. 

Certainty of Evidence for Key Question 2C

We have low certainty that robot-assisted surgery is more expensive than laparoscopic ventral 

hernia repair or open ventral hernia repair based on inconsistency and imprecision (studies were 

all observational). We have insufficient data to render a statement regarding the cost of robotassisted versus the other surgical approaches. Importantly, since there were no formal costeffectiveness analyses, no conclusion can be made in this regard as well. 
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SUMMARY AND DISCUSSION

SUMMARY OF EVIDENCE BY KEY QUESTION

Key Question 1A: What is the clinical effectiveness of robot-assisted surgery 

compared to conventional laparoscopic or open surgery for cholecystectomy? 

In general, OR time was longer in patients treated with robot-assisted cholecystectomy compared 

to laparoscopic cholecystectomy. While not always statistically significant, data are consistent 

across RCTs and observational studies. There was no evidence of differences in total intraoperative complications or conversions, and most studies had point estimates close to the null 

value. Only 5 studies reported common bile duct injuries, and there was no evidence of a

difference between robot-assisted cholecystectomy and laparoscopic cholecystectomy. Most 

studies did not demonstrate a significant difference in LOS, postoperative complications, or 

surgical site infections. Pain was variable among the studies and did not demonstrate a pattern. 

The rate of incisional hernia may be higher in the robot-assisted cholecystectomy cohort when 

performed using a single-port compared to a multi-port laparoscopic surgery. This finding is not 

unexpected and may not be an appropriate comparison, as the single-port robot-assisted 

cholecystectomy requires a larger incision than the smaller incisions needed for the multi-port 

laparoscopic cholecystectomy. Studies comparing single-port robot-assisted assisted 

cholecystectomy and single-port laparoscopic cholecystectomy were not different in hernia 

outcomes. This is an important consideration, since the single-port approach with robot-assisted 

cholecystectomy or laparoscopic cholecystectomy involves a larger incision and confers a higher 

risk for developing an incisional hernia. Thus, the interpretation of this finding may be related to 

single-port versus multi-port, not robot versus laparoscopic.

Key Question 2A: What is the cost-effectiveness of robot-assisted surgery 

compared to conventional laparoscopic or open surgery for cholecystectomy?

While there are a number of studies comparing the cost-effectiveness of robot-assisted versus

laparoscopic surgery for cholecystectomy, all had significant limitations, primarily surrounding 

the cost methodology. None were formal cost-effectiveness analysis studies. Nevertheless, there 

was an almost unanimous finding, including in the randomized data, that the robot-assisted

approach is more expensive than the laparoscopic approach. We therefore have moderate 

certainty that robot-assisted surgery is more expensive than laparoscopic cholecystectomy. 

Key Question 1B: What is the clinical effectiveness of robot-assisted surgery 

compared to conventional laparoscopic or open surgery for inguinal hernia 

repair? 

Operative room time was longer in patients treated with robot-assisted inguinal hernia repair 

compared to laparoscopic and open repair, particularly for unilateral repairs. In terms of LOS, 

there may be a signal of a small benefit favoring the robot-assisted approach compared to open 

surgery for inpatient stays. There does not appear to be a signal of benefit with regard to SSI for 

the robot-assisted approach compared to laparoscopic or open surgery. There may be a small 

signal of benefit for lower readmissions with the robot-assisted approach for unilateral hernias. 

Most studies demonstrated no difference among approaches when assessing complications and 

postoperative pain. There was no difference in hernia recurrence among all approaches. 
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Key Question 2B: What is the cost-effectiveness of robot-assisted surgery 

compared to conventional laparoscopic or open surgery for inguinal hernia 

repair? 

Only 5 studies compared costs of robot-assisted compared to laparoscopic or open surgery for 

inguinal hernia repair. All had significant limitations, primarily surrounding the cost 

methodology. Robot-assisted surgery was more expensive in these studies as compared to 

laparoscopic or open inguinal hernia repair. Based on somewhat limited directness and 

consistency in the evidence, we have low certainty that robot-assisted surgery is more expensive 

than laparoscopic or open surgery for inguinal hernia repair. Importantly, since there were no 

formal cost-effectiveness analyses, no conclusion can be made in this regard as well. 

Key Question 1C: What is the clinical effectiveness of robot-assisted surgery 

compared to conventional laparoscopic or open surgery for ventral hernia repair? 

Operating room time was longer in patients who underwent robot-assisted ventral hernia repair 

compared to both the open approach and laparoscopic approach. This was an almost universal 

finding among all the studies evaluating this outcome. Conversion to open surgery from a robotassisted approach may be less than from a laparoscopic approach. This finding was demonstrated 

in 1 matched103 and 1 unmatched study101 with a third study95 showing no difference. LOS also 

may be favored by performing a robot-assisted surgery for ventral hernia. This was a statistically 

significant difference between robot-assisted and open ventral hernia repair; however, this effect 

was not shown when compared to the laparoscopic approach. There was no evidence of

differences in readmissions, SSI, postoperative complications, and mortality. The outcome of 

recurrence was evaluated in 1 matched study96 and 5 unmatched studies76,89,93,95,97 showing no 

significant difference except in the matched study. Only 2 studies evaluated postoperative pain, 

which showed no difference between the groups of patients.96,101 

Key Question 2C: What is the cost-effectiveness of robot-assisted surgery 

compared to conventional laparoscopic or open surgery for ventral hernia repair? 

There are a handful of cases comparing the costs of robot-assisted versus laparoscopic or open 

surgery for ventral hernia repair. All had significant limitations, primarily surrounding the cost 

methodology. However, 4 of the 6 studies reported that the robot-assisted approach was more 

expensive than either the laparoscopic or open approach (with large effect size) and the other 2 

studies reported no difference in cost as compared to laparoscopic repair. As seen for 

cholecystectomy and inguinal hernia, no cost-effectiveness studies were identified. 

LIMITATIONS

Publication Bias

We were not able to test for publication bias and can make no conclusions about its possible 

existence. However, we believe it is extremely unlikely that there exists a high-quality 

randomized trial of robot-assisted surgery versus other surgical approaches that we did not 

identify, and has similarly escaped detection by all other experts in this field. There are probably 

a plentitude of observational experiences about robotic therapies, from individual institutions, 

that have never been published, and the published literature likely represents only a small 

fraction of what could be known using observational studies. 
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Study Quality

The randomized trials for were judged to be at low risk of bias for short-term outcomes, like 

intraoperative and postoperative outcomes. They were judged to be at moderate risk of bias for 

longer-term outcomes. Likewise, the observational studies were judged to be at moderate risk of 

bias (due to their non-random assignment of treatments) for short-term outcomes and high risk of 

bias for longer-term outcomes. 

Heterogeneity

As mentioned, the studies were very heterogeneous across patient and technique factors as well 

as how the outcomes were measured. Since we only found 4 RCTS for cholecystectomy, 1 for 

inguinal hernia repair, and 1 small RCT for ventral hernia repair, the vast majority of our data 

was observational. There are potential strong selection biases by the surgeons for when they 

would choose to perform a robot-assisted case over the standard approaches – which often leads 

to differences in the comparative groups, which we saw in the studies included in our review. 

The technique used for the robot-assisted approach is also different – how the mesh is secured, 

fascial closure, bilateral repair, or number of ports. 

Some outcomes had heterogeneous measurements across studies. These included: OR time, LOS, 

and pain. OR time was most commonly reported as skin cut time to closure, but others reported

the room time, console time, or didn’t define their measurement. Length of stay was also 

challenging to compare across studies as these operations could be performed as outpatient or 

inpatient and there was often a mix of time scale between or within studies. Pain as an outcome 

was reported using a variety of measures: different scales, variable time intervals, receipt of pain 

medications, time needing pain medication, and occurrence of chronic nerve pain. This greatly 

limited the ability to compare results across studies. 

Applicability of Findings to the VA Population

Only 2 studies were specific to VA populations – 1 for cholecystectomy29 and 1 for inguinal 

hernia repair67 – therefore strong conclusions from this data cannot be made. Unfortunately, we 

are not aware of any robotic cost data within the VA, but utilization data is available and this 

may serve as a first step towards future research in this area. 

However, the applicability of these results to VA populations may depend on both the similarity 

of the patients studied to VA patients and the experience of the surgical teams using the robot to 

VA surgical team experience. Yet the benefits for robot-assisted approach may still be realized 

despite patient-level differences (VA patient population has greater burden of comorbidities than 

the general population), which will need to be confirmed in future studies. Urology as a surgical 

field has widely adopted robot-assisted surgery, so this experience will likely translate well into 

the expansion of robot-assisted approach to general surgery in the VA setting. 

Research Gaps/Future Research

Numerous research gaps are apparent. There is a need for randomized data or propensity 

matching that addresses patient- and technique-related factors. The variability in the use of the 

robot-assisted approach based on these factors currently limits the ability to compare across 

study arms, as variations at baseline or differences in how the operation was performed are large 
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and may likely be responsible for realized clinical differences or lack thereof. Importantly, there 

are advantages of the robot that are clear and notable – enhanced, three-dimensional 

visualization, augmented dexterity and range of motion, reduction of tremor, to name a few. The 

heterogeneous nature of the studies limited the ability to show how these features translate into 

better clinical outcomes. Studies that control for key patient factors, case complexity, technical 

aspects of procedures, and surgeon experience may provide insight into this overarching 

question. Additionally, adequate long-term follow-up for certain outcomes is greatly needed. 

Several areas warrant specific discussion. 

Surgeon Learning Curve

The surgeon learning curve is a well-characterized surgical concept that has similarly been 

applied to robot-assisted surgery. As with any new platform the need for training, practice, and 

experience is needed. Even open surgical procedures, such as pancreatectomy, suffer from 

inexperienced surgeons that require tutelage before displaying mastery of the technique. The 

advent of laparoscopy more than 30 years ago brought this concept more into the forefront and 

showed the impact of surgeon learning curves on clinical patient outcomes. Likewise, surgeon 

learning curve for robot-assisted cases is a multifaceted issue. Previous reviews found that the 

surgeon experience (ie, ability as a function of cases completed) is fluid, as it has multiple phases 

and surgeons tend to add increasingly complex patient cases as they gain experience.

1

 In our 

review, we found that 90% of the studies for robot-assisted cholecystectomy acknowledged the 

possibility of a learning curve; however, only 5/46 provided data/assessment (and findings on 

OR time and incisional hernia occurrence were mixed).

22,23,29,34,37 A learning curve impact may 

likely vary by procedure as well. Research assessing surgeon experience needs to include a 

variety of clinical outcomes, not just efficiency such as OR time. With emerging technologies, 

research should routinely comment on and address the potential impact the level of experience of 

the surgeon or surgeons played.

Resident Training

Robotics as an evolving technology is also changing how surgical residents are educated. 

Furthermore, faculty surgeons need to gain their own experience while balancing training 

residents. 1 recent survey of program directors by Tom et al found that a 92% of programs have 

residents participating in robot-assisted surgery, while 68% offer formal curriculum; 44% track 

residents’ robot-assisted experience, and about half (55%) recognize curriculum training 

completion.

109 Another study also found wide variations “in requisite components, formal 

credentialing, and case tracking and role of simulation training”.110 There is also no standardized 

approach on how to incorporate this training based on level of trainee. Overall, there is a need to 

adopt a standardized training curriculum and document resident competency.111 

Long-term Follow-up

Our work identified a lack of high-quality evidence with adequate long-term follow-up and 

sufficient statistical power to properly assess clinical outcomes between the operative approaches 

for inguinal hernia repair and ventral hernia repairs. For hernia repairs, outcomes of interest need 

to include recurrent hernias beyond 1 year, long-term pain, and functional status. Only 1 small 

RCT was found for ventral hernia repair, none for inguinal, and it only reported on 1 main 

outcome of interest. The data we found was too limited to provide conclusions in this regard. 
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Cholecystectomy Research Gaps

Our review focused on use of robot-assisted surgery for benign, elective gallbladder disease. 

However, there is a need for future studies on cholecystectomy for non-benign pathology and 

emergent cases. As the robot-assisted technique is becoming more common, certain institutions 

are beginning to use it for cancer cases and non-elective surgeries, which are notably more 

complex. Given the differences in patient populations that experience these indications and the 

higher rates of complications for non-elective surgeries, the results from our study may not be 

generalizable to these populations. In fact, the robot-assisted approach may prove to be 

particularly advantageous for these more complex cases. The study of differences in cancer 

outcomes, and morbidity, for robot-assisted versus laparoscopic and open surgery is essential. As 

such, future research may consider expanding this review to examine different indications for 

cholecystectomy. 

Inguinal Hernia and Ventral Hernia Repair Research Gaps

Specific to hernia repairs, the robot-assisted approach may offer several technical advantages. 

For inguinal hernias, the potential for avoiding tacks or even the need for suturing mesh 

(sutureless mesh) may lead to less postoperative acute and chronic pain. For ventral hernia, the 

robot-assisted approach with improved suturing technique can also forego placement of tacks as 

well as possibly decrease recurrent hernia formation. Unfortunately, these technical details were 

not uniformly available across the studies in our review and outcomes were typically not 

reported by these factors. As such, it was not possible to determine their specific roles. 

Additionally, baseline pain was often not reported, perioperative quality of life and pain data 

were sparse, and long-term data on chronic pain and recurrence were rare. Standardized 

reporting in future work is needed in order to sufficiently assess pain outcomes. Guidance should 

be provided on reporting technical aspects of the repair and requirements for clinical outcome 

assessment – for instance, specific time intervals, tools for assessing pain, and amount of pain 

medications taken. 

Ergonomics for the Surgeon

An important issue that deserves study is the impact of the robot-assisted approach on the 

physical stress on the surgeon performing the operation. There is a high rate of musculoskeletal 

disorders attributed to poor ergonomics of laparoscopic surgery as well as the open approach. 

There are those that claim robot-assisted surgery ergonomics are superior, leading to decreased 

physical stress and workload. However, there is also growing evidence that a prolonged time 

sitting at the robot-assisted console adds new physical challenges as well.112 Two recent studies 

reported physical discomfort and symptoms113 or poor posture114 in over half of surgeons. 

Although data are sparse, it would be a valuable area for future research. While challenging to 

study, the outcomes would need to be comparative, long-term (5 year plus) and would require 

assessing detailed quality of life, assessment of chronic physical injuries, and longevity of 

operating over a career.

Future Innovation in Surgical Robotics

An overwhelming number of the studies in our review used the da Vinci system from Intuitive 

(only 1 study used the Senhance robot).22 The robotic field is changing soon, as a number of new 

robotic platforms are becoming available; there are 8 with FDA approval, and more pending 
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approval.5

 These will bring with them potentially new advantages (eg, improved computer 

optics, machine learning, and automation) and possibly new challenges (eg, different technology 

with new learning curves, unknown impact on patient outcomes). Future research will be critical 

to assess the differences between these technologies. With these new market forces, there is 

anticipation for reduced cost as well.

Conflict of Interest

It is notable that reporting bias in robot-assisted surgery research has been identified. A recent 

study found that author payments from Intuitive were not declared in more than half (52%) of 

robot-assisted surgery research,

115 and they reported more positive findings as compared to those 

that did declare their conflict of interest (COI) payments. There is a need to ensure full disclosure 

of COI with more accountability and journals may want to adopt standardized processes to 

achieve better transparency.

Costs

Lastly, the lack of well-designed comparative studies also limits evaluations of cost. There is a 

need for standardized approaches to assess cost, which would apply to all 3 of these robotassisted operations (ie, analytics approach, consistent definitions of cost, how upfront capital was 

accounted for, how to adjust for training staff, etc). Along these lines, formal cost-effectiveness 

studies that weigh the benefits and risks along with cost are needed. 

Conclusions

Across 3 common general surgery procedures there is evidence that OR time is longer for the 

robot-assisted approach, and some signals that select intraoperative and postoperative 

complications are more favorable with the robot-assisted approach based on the operation. 

Overall, the studies were heterogeneous in terms of patient characteristics and how the 

operations were performed and definitive conclusions cannot be made. Cost is probably higher 

across these procedures, but the balance between the added expense and potential gains in 

effectiveness are unknown, until we adopt better, standardized methods of assessment.
Robot-assisted Procedures in General Surgery Evidence Synthesis Program

79

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APPENDIX A. SEARCH STRATEGIES

CHOLECYSTECTOMY

DATABASE SEARCHED & TIME PERIOD COVERED:

Pubmed – 2010-2020

"Robotic Surgical Procedures"[Mesh] OR robotics[mh] OR robot-assisted OR robot*[tiab] OR robot*[ot] 

AND 

cholecystectomy[tiab]OR cholecystectomies[tiab])) OR cholecystectomy[MeSH]

AND 

"2010"[Date - Publication] : 2020[Date - Publication]

DATABASE SEARCHED & TIME PERIOD COVERED:

EMBASE – 2010-2020

'robot assisted surgery'/exp OR 'robot assisted surgery' OR 'robot assisted' OR robot* 

AND

Cholecystectomy/exp OR Cholecystectomy OR Cholecystectomies 

AND

Publication years 2010-2020

DATABASE SEARCHED & TIME PERIOD COVERED:

Cochrane 2010-2020

Robotic assisted surgical procedures OR robotics OR (MESH descriptor)Robotic Surgical 

Procedures/exp OR (MESH descriptor)Robotics/exp 

AND

(MESH Descriptor)Cholecystectomy/exp OR (Cholecystectomy OR Cholecystectomies)ti,ab,kw 

AND

Publication years Jan 2010-Dec 2020 

INGUINAL HERNIA

DATABASE SEARCHED & TIME PERIOD COVERED:

PUBMED – 2010-2020 

"Robotic Surgical Procedures"[Mesh] OR robotics[mh] OR robot-assisted OR robot*[tiab] OR 

robot*[ot] 

OR

surgical mesh or open surgical technique* or open operative technique* or open suture repair* or 

mesh repair*

OR 

"Abdominal Wall/surgery"[Mesh] OR "Hernia, Ventral/surgery"[Mesh]

AND 
Robot-assisted Procedures in General Surgery Evidence Synthesis Program

88

Hernia, Inguinal[MESH] OR “inguinal hernia” OR “inguinal hernias” OR Groin[MESH] OR 

Groin or groins 

AND 

(limit) Humans 

AND 

(limit) adult

AND 

 

"2010"[Date - Publication] : "2020"[Date - Publication] 

DATABASE SEARCHED & TIME PERIOD COVERED:

EMBASE – 2010 - 2020 

'robot assisted surgery'/exp OR 'robot assisted surgery' OR 'robot assisted' OR robot* 

AND

‘inguinal hernia/exp OR inguinal region/exp OR “inguinal hernia” OR “inguinal hernias” OR 

groin OR groins

AND

Human/de 

AND 

adult/lim OR aged/lim OR very elderly/lim

AND

Publication years 2010-2020 

DATABASE SEARCHED & TIME PERIOD COVERED:

COCHRANE Reviews – 2010- Dec 2020 

 

Robotic assisted surgical procedures OR robotics OR (MESH descriptor) Robotic Surgical 

Procedures/exp OR (MESH descriptor)Robotics/exp 

AND

1. explode inguinal hernia (MeSH) 

2. inguinal herni* ti,ab,kw 

3. shouldice. ti,ab,kw 

4. bassini. ti,ab,kw

5. mcvay. ti,ab,kw 

6. stoppa.t ti,ab,kw

7. (laparoscop* NEAR25 herni*) ti,ab,kw 

8. (tension‐free NEAR25 herni*) ti,ab,kw

9. (conventional NEAR25 herni*). ti,ab,kw 

10. (open NEAR25 herni*). ti,ab,kw 

11. (darn NEAR25 herni*). ti,ab,kw 

12. (mesh NEAR25 hern*). ti,ab,kw 

13. (traditional NEAR25 herni*) ti,ab,kw 

14. (plug NEAR25 herni*).t ti,ab,kw 
Robot-assisted Procedures in General Surgery Evidence Synthesis Program

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15.(lichtenstein NEAR25 herni*).tw 

16. 1 or 2 or 3 or 4 or 5 or 6 or 7 or 8 or 9 or 10 or 11 or 12 or 13 or 14 or 15 

AND

Publication years Jan 2010- Dec2020 

Notes on ENL: 

Created separate ENL for Cochrane which was deduped and then copied into other ENL

keyword: child, manually reviewed and deleted records 

DATABASE SEARCHED & TIME PERIOD COVERED:

OVID MEDLINE & Epub Ahead of Print, In-Process & Other Non-Indexed Citations and Daily 

- 1946 to March 26, 2020) 

1. exp Hernia, Ventral/su [Surgery]

2. Abdominal Wall/su [Surgery]

3. (surgical mesh or open surgical technique* or open operative technique* or open suture 

repair* or mesh repair*).mp. [mp=title, abstract, original title, name of substance word, subject 

heading word, floating sub-heading word, keyword heading word, organism supplementary 

concept word, protocol supplementary concept word, rare disease supplementary concept word, 

unique identifier, synonyms] 

4. 1 or 2 or 3 

5. Hernia/

6. exp Hernia, Inguinal 

7. Groin/ 

8. inguinal hernia or inguinal hernias or groin or groins 

9. 5 or 6 or 7 or 8 

10. 4 and 9 

Limit – humans, 2010-2020, young adult, adult, middle age, middle aged, all aged 

VENTRAL HERNIA

DATABASE SEARCHED & TIME PERIOD COVERED:

PUBMED – 2010-2020 

"Robotic Surgical Procedures"[Mesh] OR robotics[mh] OR robot-assisted OR robot*[tiab] OR 

robot*[ot] 

AND

“surgical mesh” or “open surgical technique*” or “open operative technique*” or “open suture 

repair*” or “mesh repair*” 

OR 

"Abdominal Wall/surgery"[Mesh] OR "Hernia, Ventral/surgery"[Mesh]

 

AND 
Robot-assisted Procedures in General Surgery Evidence Synthesis Program

90

 

"ventral hernia" OR "incisional hernia"

OR 

ventral hernia or incisional hernia

OR 

"Hernia"[Mesh]) 

OR 

“Hernia, Ventral"[Mesh]

 

AND 

(limit) Humans 

AND 

(limit) adult

AND

"2010"[Date - Publication] : "3000"[Date - Publication] 

DATABASE SEARCHED & TIME PERIOD COVERED:

EMBASE - 2010-2020 

 

'robot assisted surgery'/exp OR 'robot assisted surgery' OR 'robot assisted' OR robot*

AND

Abdominal wall hernia/exp OR incisional hernia/exp OR umbilical hernia/exp OR epigastric 

hernia/exp OR 'incisional hernia' OR 'incisional hernias' OR 'ventral hernia' OR 'ventral hernias' 

OR 'umbilical hernia' OR 'umbilical hernias' OR 'epigastric hernia' OR 'epigastric hernias' 

AND

Human/de 

AND 

adult/lim OR aged/lim OR very elderly/lim

AND

Publication years 2010-2020 

DATABASE SEARCHED & TIME PERIOD COVERED:

COCHRANE – Jan 2010 – Dec 2020 

Robotic assisted surgical procedures OR robotics OR (MESH descriptor) Robotic Surgical 

Procedures/exp OR (MESH descriptor)Robotics/exp

AND

Incisional hernia(Mesh descriptor)/exp OR Hernia, ventral(Mesh descriptor)/exp OR Hernia, 

umbilical (Mesh descriptor)/exp OR “incisional hernia” OR “Incisional hernias” OR “ventral 

hernia” OR “ventral hernias” OR “umbilical hernia” OR “umbilical hernias” OR “epigastric 

hernia” OR “epigastric hernias”:ti,ab,kw

AND

Publication years Jan 2010- Dec2020 

NB: results reviewed for animal and children exclusion
Robot-assisted Procedures in General Surgery Evidence Synthesis Program

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DATABASE SEARCHED & TIME PERIOD COVERED:

OVID MEDLINE & Epub Ahead of Print, In-Process & Other Non-Indexed Citations and 

Daily (1946 to March 26, 2020) – 

 

1. exp Hernia, Ventral/su [Surgery]

2. Abdominal Wall/su [Surgery] 

3. (surgical mesh or open surgical technique* or open operative technique* or open suture 

repair* or mesh repair*).mp. [mp=title, abstract, original title, name of substance word, subject 

heading word, floating sub-heading word, keyword heading word, organism supplementary 

concept word, protocol supplementary concept word, rare disease supplementary concept word, 

unique identifier, synonyms] 

4. 1 or 2 or 3 

5. Hernia/

6. exp Hernia, Ventral/ 

(ventral hernia or incisional hernia).mp. [mp=title, abstract, original title, name of substance 

word, subject heading word, floating sub-heading word, keyword heading word, organism 

supplementary concept word, protocol supplementary concept word, rare disease 

supplementary concept word, unique identifier, synonyms] 

8. 5 or 6 or 7

9. 4 AND 8

AND 

Humans (limit)

AND

Young adult OR adult Or middle age OR middle aged or all aged OR aged (limit) 

AND

2010-1091 (limit) 
Robot-assisted Procedures in General Surgery Evidence Synthesis Program

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APPENDIX B. PEER REVIEWER COMMENTS AND 

RESPONSES 

Reviewer comment Authors Responses

Note to the reviewers, we updated our search 

through April 2020. This added a handful of studies 

(5 cholecystectomy; 4 inguinal hernia repair; 4 

ventral hernia repair). 1 inguinal study is an RCT.

These did not change our main conclusions.

Yes - Throughout this very well written manuscript 

there is a biased assumption that the capabilities 

of surgeons operating laparoscopically and 

robotically are similar. This would be the majority 

view but I strongly believe that it is incorrect. 

Robotic instruments and integrated real 3 

dimensional vision generated by 2 cameras, 1 for 

each eye is vastly different than laparoscopy. 

Could robotic procedures be longer because 

surgeons are seeing better and working safer?

Could robotic procedures take longer because 

more complex cases are being performed?

Are robotic procedures taking longer because the 

staff are less experienced?

Where are robotic surgeons in their learning 

curves within all of these studies? Laparoscopy 

has been main stream for more than 30 years so 

the experience of surgeons with laparoscopy 

would have to be significantly higher.

Yes. We agree that the robot offers clear 

advantages and have added comments about these 

to the Discussion. 

 

Thanks for your other comments. We expanded our 

Discussion section on: increased OR time/ safer; 

complexity of cases; learning curves. 

Yes - As the authors know, the topic of robotic 

use in General Surgery is a very fluid and hot 

topic. Because the literature is continually 

changing with new studies, albeit, not RCTs, it is 

really difficult to make definitive conclusions. 

There was a recent study in the last 6 months 

comparing robotic and laparoscopic ventral hernia 

repair and concluded no difference in outcomes 

studied. The outcome that is not typically included 

in most studies is postoperative pain for all 3 

procedures. Many experts feel the major benefit 

of robotic repair of both incisional and inguinal 

hernias is the avoidance of using tacks. The 

ability to use intra-corporal sewing with the robot 

for securing mesh with ventral hernias and 

avoiding tacks does reduce postop pain. 

Similarly, the use of mesh that eliminates the 

need for sutures for robotic inguinal hernia repair 

definitely reduces acute and chronic pain for 

these patients. So perhaps comments in these 2 

areas would be helpful for the reader. I agree with 

the authors that it is really hard to justify by any 

outcome that there is a benefit to using a robot for 

cholecystectomy.

Yes. Thank you for your suggestion. We added 

comments to our Discussion about 1) benefit of 

robotic approach for hernia repairs as tacks aren’t 

used; 2) sutureless mesh. 

Thank you for this comment. We are working 

several manuscripts to submit. 
Robot-assisted Procedures in General Surgery Evidence Synthesis Program

93

Compliments to the authors for an excellent 

review. Suggest you convert this into a 

manuscript that could be published in a surgical 

journal.

Edits recommended as below:

Page 4, Lines 32-40: Degrees/titles edited; 

recommend deletion of mailstops (10NC2)

Mark A. Wilson, MD, PhD

National Director of Surgery (10NC2)

Department of Veterans Affairs

William Gunnar, MD

Executive Director, National Center for Patient 

Safety

Former National Director of Surgery (10NC2)

Department of Veterans Affairs

Page 6, Lines 25-44: Capitalization is not 

consistent. Standardize terminology to robotassisted for all uses.

RESULTS 

...............................................................................

................................................... 19

Key Question 1A – Cholecystectomy: What is the 

clinical effectiveness of robot-assisted

surgery compared to conventional laparoscopic 

surgery for cholecystectomy?....................... 23

Key Question 2A – cholecystectomy: what is the 

cost-effectiveness of robot-assisted surgery

compared to conventional laparoscopic surgery 

for cholecystectomy? .................................... 30

Key Question 1B – inguinal hernia surgery: What 

is the clinical effectiveness of robot-assisted

surgery compared to conventional laparoscopic or 

open surgery for inguinal hernia repair? 38

Key Question 2B – Inguinal Hernia Surgery: what 

is the cost-effectiveness of robotic-assisted

surgery compared to conventional laparoscopic 

OR open surgery for inguinal hernia repair?

...............................................................................

..................................................................... 47

Key Question 1C – VentraL hernia surgery: What 

is the clinical effectiveness of robotic assisted

surgery compared to conventional laparoscopic or 

open surgery for ventral hernia

repair?....................................................................

.................................................................... 49

Key Question 2C – Ventral Hernia Surgery: what 

is the cost-effectiveness of robot-assisted

surgery compared to conventional laparoscopic 

OR open surgery for ventral hernia repair? 59

Thank you for your edits. These corrections were 

made. 

These corrections were made.
Robot-assisted Procedures in General Surgery Evidence Synthesis Program

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Page 8, Lines 39-33: Delete mailstops (10NC2); 

add current title for Dr. Gunnar as below:

This topic was developed in response to a 

nomination by Dr. Mark Wilson, National Director 

of

Surgery (10NC2), and Dr. William Gunnar, 

Executive Director, National Center for Patient 

Safety and former National Director of Surgery 

(10NC2). Key questions were then developed 

with input from the topic nominator, the ESP 

coordinating center, the review team, and the 

technical expert panel (TEP).

Very nice review. I have a couple minor 

edits/suggestions.

Page 7, line 42 would add ....We assessed 

robotic and laparoscopic approach for 

cholecystectomy, as open cholecystectomy is 

typically performed for cancer pathology or in the 

setting of significant inflammation or adhesive 

disease.

page 7 line 49 ,...in order (to) lessen confounding 

factors

page 8 line 20. not sure what is meant by 

"technique factors"....

page 41 line 11 - I think there are extra tick marks 

for length of stay. 

I suspect that the learning curve of robotic 

general surgery played a large part in increased 

operative times. Most of the studies compared 

early surgeon experience with the robot 

compared with years of experience 

laparoscopically. Perhaps a reference about 

learning curve and robotic surgery could be 

included. 

Inguinal hernia repairs and cholecystectomies 

rarely require inpatient hospitalization. This 

should be noted.

Requested edits were made to pages 7-8. 

For page 41 comment: These studies reported 

inpatient and outpatient LOS so both were listed.

We now display only outpatient values which 

generalizes better to how most are done. 

We added a clarification that inguinal hernias and 

cholecystectomy are mainly outpatient procedures. 

Robotic surgery is an exciting field with more 

advanced procedures being performed daily. 

Although the technology has been available for 

years there is still a learning curve for the surgeon 

and may be reflected by longer case times 

initially. As it becomes more integrated into 

practice I foresee the benefits will rise. 

This review is a great resource for those 

interested in robotic general surgery and how it 

compares to laparoscopic and open surgery. The 

authors skillfully reviewed many studies and have 

Thanks for the comments. We added to the 

Discussion more specifics about the potential 

learning curve. 

It is possible that more complex gallbladder cases 

are preferentially done with the robot, but this was 

hard to assess with the studies as case complexity 

wasn’t defined well for the benign disease. RCTs for 

cholecystectomy should control reasonably well for 

this potential difference. We also added comments 
Robot-assisted Procedures in General Surgery Evidence Synthesis Program

95

put together a comprehensive overview of the 

data we have thus far. Thank you for 

acknowledging the limitations of all these 

heterogenous studies. 

Page numbers based on pdf document, not those 

printed on the text. 

Cholecystectomy: 

Did the studies look at difficulty of gallbladder 

surgery? Ie were the robotic gallbladders done 

because of an expected difficult surgery vs 

laparoscopic technique? This is alluded to further 

in the discussion as a selection bias. 

Inguinal hernias: 

Pg 11: Again was the difficulty of the hernias 

looked at in the demographics and case 

matching? I would always choose a robotic repair 

over laparoscopic if expected to be difficult 

(patient obesity, size of hernia defect, 

incarceration, bowel involvement). 

Since the cost effectiveness sections all came to 

the same conclusions perhaps they could be 

condensed into 1 section. 

Discussion: 

Differences in OR time across studies is possibly 

due to docking time of the robot but an efficient 

team can do this in 10 minutes or less. I would 

also be careful placing a lot of weight on the 

differences in OR time especially if not a great 

time difference between technique. Faster is not 

necessarily better for the patient. I think a lot of 

the difference is due to the learning curve with 

starting robotic surgeries, the efficiency of the OR 

team and mostly the difficulty of the case. When 

choosing a surgical technique for hernia or 

gallbladder I always consider the robot when I 

anticipate a case to be more difficult. Ie larger 

hernia, incarcerated bowel, recurrence hernia, 

chronic cholecystitis with PCT. These cases will 

always take me longer because of the difficulty 

not because of the robot. 

The LOS is a hard measure to compare as most 

of these cases are done outpatient regardless of 

technique. Again I don't think there is a big clinical 

impact here but all the studies mention it. 

As for the cost I agree that no conclusions can be 

made based on the evidence. These sections 

could be condensed into 1 for cholecystectomy 

and hernias. 

Does the VA have any cost data to look at 

internally? 

“Urologic surgery has been widely

adopted in the VA, so this experience for the staff 

may translate into an easy implementation to

about use of robot for more complex cases 

including cancer in the Discussion. 

We added more cost data and have chosen to 

present them by the individual procedures. Cost 

range is quite different between these groups so it 

seems better to keep them separate. 

Differences between study arms for hernias were

multi-factorial. Sometimes matching was on patient 

factors, but not for hernia size or complexity. And 

sometimes visa versa. Standardized matching 

across studies on the most pertinent factors would 

be very useful. Studies typically matched based on 

the available variables available in their dataset. 

This comment was added to our Discussion as well. 

We added comments to address your points –

gallbladder difficulty was poorly assessed for 

observational studies. 

Yes. The difficulty of cases for inguinal hernias was 

also hard to assess. Particularly for inguinal hernias, 

there were gaps in reported information to assess. 

We did our best to control for laterality (unilateral, 

bilateral) as this would greatly impact outcomes we 

were interested in.

Unfortunately, we are not aware of any cost data 

within the VA. We are in the process of accessing 

VA utilization data on robotic surgery. A comment 

on this was added to the Discussion section. 
Robot-assisted Procedures in General Surgery Evidence Synthesis Program

96

the robotic general surgery field.” I agree with this 

statement. Most OR staff is familiar with robotic 

surgery and adept at use. 

Research Gaps: 

Agree with surgeon learning curve affecting 

outcomes of studies. Additionally the difficulty of 

cases effects outcomes. 

Agree with need for long term follow up to prove 

hernia recurrence is lower or higher for each 

technique. 

Cholecystectomy for cancer should be considered 

on its own for clinical effectiveness. This 

operation may involve a partial hepatectomy 

depending on pathology. 

Additionally studies need to clearly compare 

cases based on the difficulty as I mentioned 

earlier. A small ventral hernia with no adhesions 

or bowel involvement can be done in 1-2 hours, 

whereas a larger ventral hernia with need for 

adhesiolysis and component release will take 3-5 

hours. 

Surgeon experience is a critical component in 

deciding which technique to use. At the end of the 

day the best operation for the patient is the 1 the 

surgeon is most experienced with.

I do not foresee many RRT being done for robotic 

vs laparoscopic vs open surgery in the future. The 

robotic surgery platform is taking off and has 

been proving itself without these trials.

This is an exhaustive review and is balanced well 

with the exception of the bias that I perceive as 

described above. It is clear that the authors have 

worked very dilligently to use language that 

avoids this bias against robotics but I would 

consider adding a section related to the expanded 

capabilities that robotic surgery has offered. 

For example lap inguinal hernias nation wide 

never exceeded 20% of total cases. However, 

with the addition of robotically trained inguinal 

hernia surgeons large markets, not just individual 

surgeons, now are able to offer minimally invasive 

inguinal hernia surgery to greater than 40% of an 

entire market. Personally, I saw my busy inguinal 

practice go from 60%mis 40%open to 95%MIS vs 

5%open with the addition of the robotic platform 

to my armamentarium of procedures that I may 

thoughtfully offer to patients. The end result is 

that more patients are able to have an MIS hernia 

repair and this increased cost is worth it to each 

patient that has shorter times of lifting restrictions, 

less opioid utilization, earlier return to full activity, 

and earlier return to work.

Thanks for the comment. We added text about the 

expanded capabilities of robotic surgery to the 

Discussion section. 

We added to the Discussion the importance of 

balancing added cost with potential benefits to the 

patient. 
Robot-assisted Procedures in General Surgery Evidence Synthesis Program

97

The authors should be commended for 

synthesizing a large amount of data that stems 

from very disparate data sources with variable 

methodologies and end points. The authors 

appropriately used the GRADE methodology to 

rate the quality of the evidence. They also 

appropriately noted that data was too 

heterogenous to allow for meta-analysis and 

instead presented this as a systematic narrative 

review of the evidence. The authors clearly 

delineated their search strategy and analytic 

framework. They also note limitations in the 

study, including the learning curve effect of 

robotic surgery as the newer technology which 

may predispose towards higher costs and longer 

operative times for the newer procedures. The 

authors do address risk of bias in the published 

data but primarily discuss this in terms of 

publication bias and not selection or author bias. 

There is excellent literature that suggests that 

there is significant bias in published reports of 

robotic surgery, and specifically that studies with 

unreported Conflict of Interest are significantly 

more favorable towards robotics (example: 

https://www.ncbi.nlm.nih.gov/pubmed/28700443)

The data seems clear that robotic surgery takes 

longer. There are some limited indications that a 

few selected patient outcome metrics are 

improved with robotics compared to open surgery 

and that conversion to open surgery may be less 

often needed in robotics compared to 

laparoscopy. There is 1 area were robotic surgery 

seems to be have clinically worse outcomes, 

notably single port robotic surgery leading to 

higher incisional hernia rates compared to 

multiple port laparoscopy. Because the studies 

were selected as RCTs or case comparisons, the 

data sources are unable to answer an important 

question of whether robotics allows some cases 

to be done via a minimally invasive approach as 

opposed to an open approach. Robotic advocates 

often claim that the robot allows some procedures 

to be done minimally invasively instead of open, 

but some market data in hernia surgery suggests 

that more cases seem to be converting from 

laparoscopic to robotic, as opposed to open 

cases transitioning to robotic. Studies looking at 

market adoption of robotic surgery could help 

answer this question, but would require an 

additional avenue of analysis. Costs seem to be 

higher in robotics, but due to limitations in data 

and methodology this is less certain, and likely 

varies depending on the particulars of an 

operation and the method of accounting. For 

example, the costs of robotic acquisition are 

Excellent point, we have added a sentence about 

the evolution of the robotic platform to other 

companies and types of technology.

Thank you for your comment. We have added these 

additional gaps in the Discussion. 

We added several additional research gaps to the 

Discussion, including the ones listed here: surgeon 

ergonomics, surgical education, learning curve, and 

anticipated new robotic platforms. 
Robot-assisted Procedures in General Surgery Evidence Synthesis Program

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handled variably across studies, as is the cost of 

length of stay data.

The authors use their systematic review to 

identify 4 areas with a research gap as a guide to 

future research. These areas are well considered 

and are all worthy of future study. Because the 

literature review focused on patient outcomes and 

cost, the identified research gaps are obviously 

focused on these areas. There are several major 

research gaps not identified in this review as they 

do not directly arise in the types of studies 

considered in this analysis:

1) Surgeon ergonomics and workload. Surgeons 

have a very high rate of musculoskeletal 

disorders due to the ergonomic challenges of 

both open and laparoscopic surgery. Advocates 

for robotic surgery often allege that ergonomics 

are improved and surgeon 

stress/workload/fatigue is decreased with robotic 

adoption, and postulate that this will result in 

improved surgeon longevity. Although data in this 

area is sparse, it would be a valuable additional 

area for future research.

2) Surgical education and learning curve. 

Robotics is a new and evolving technology. This 

is creating major issues in surgical education - 

both in education of surgical trainees and also in 

education of surgeons in practice who are 

learning new approaches. The advent of 

laparoscopy more than 20 years ago showed the 

importance of education and learning curves, as 

patient injury rates skyrocketed during the early 

years of laparoscopic surgery. 

3) Future innovation in surgical robotics. Although 

not discussed in the review, all of the studies 

addressed here are using the da Vinci system 

from Intuitive. There are several new robotic 

platforms that will soon be available, and these 

will come with new opportunities and challenges 

with regard to technical issues, patient outcomes, 

and costs. Additionally, robotic platforms offer the 

potential for new advances in computer vision, 

machine learning, and automation that may 

transform the surgical landscape. These are 

areas rife with research opportunities.
Robot-assisted Procedures in General Surgery Evidence Synthesis Program

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APPENDIX C. COCHRANE RISK OF BIAS TOOL

The Cochrane Collaboration’s Tool for Assessing Risk of Bias* 

Domain Support for judgement Review authors’ judgement

Selection bias.

Random sequence 

generation.

Describe the method used to generate the 

allocation sequence in sufficient detail to allow an 

assessment of whether it should produce 

comparable groups.

Selection bias (biased allocation to 

interventions) due to inadequate 

generation of a randomised sequence.

Allocation concealment. Describe the method used to conceal the allocation 

sequence in sufficient detail to determine whether 

intervention allocations could have been foreseen 

in advance of, or during, enrolment.

Selection bias (biased allocation to 

interventions) due to inadequate 

concealment of allocations prior to 

assignment.

Performance bias.

Blinding of participants 

and personnel 

Assessments should be 

made for each main 

outcome (or class of 

outcomes).

Describe all measures used, if any, to blind study 

participants and personnel from knowledge of 

which intervention a participant received. Provide 

any information relating to whether the intended 

blinding was effective.

Performance bias due to knowledge 

of the allocated interventions by 

participants and personnel during the 

study.

Detection bias.

Blinding of outcome 

assessment Assessments 

should be made for each 

main outcome (or class of 

outcomes). 

Describe all measures used, if any, to blind 

outcome assessors from knowledge of which 

intervention a participant received. Provide any 

information relating to whether the intended 

blinding was effective.

Detection bias due to knowledge of 

the allocated interventions by 

outcome assessors.

Attrition bias.

Incomplete outcome 

data Assessments should 

be made for each main 

outcome (or class of 

outcomes).

Describe the completeness of outcome data for 

each main outcome, including attrition and 

exclusions from the analysis. State whether 

attrition and exclusions were reported, the 

numbers in each intervention group (compared 

with total randomized participants), reasons for 

attrition/exclusions where reported, and any reinclusions in analyses performed by the review 

authors.

Attrition bias due to amount, nature 

or handling of incomplete outcome 

data.

Reporting bias.

Selective reporting. State how the possibility of selective outcome 

reporting was examined by the review authors, 

and what was found.

Reporting bias due to selective 

outcome reporting.

Other bias.

Other sources of bias. State any important concerns about bias not 

addressed in the other domains in the tool.

If particular questions/entries were pre-specified 

in the review’s protocol, responses should be 

provided for each question/entry.

Bias due to problems not covered 

elsewhere in the table.

* http://handbook.cochrane.org/ in Table 8.5.a
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APPENDIX D. RISK OF BIAS IN NON-RANDOMISED STUDIES 

– OF INTERVENTIONS (ROBINS-I)

Bias domains included in ROBINS-I10

Pre-intervention Risk of bias assessment is mainly distinct from assessments of randomised 

trials

Bias due to

confounding

Baseline confounding occurs when 1 or more prognostic variables (factors that 

predict the outcome of interest) also predicts the intervention received at 

baseline

ROBINS-I can also address time-varying confounding, which occurs when 

individuals switch between the interventions being compared and when postbaseline prognostic factors affect the intervention received after baseline

Bias in selection of

participants into the

study

When exclusion of some eligible participants, or the initial follow-up time of 

some participants, or some outcome events is related to both intervention and 

outcome, there will be an association between interventions and outcome even 

if the effects of the interventions are identical

This form of selection bias is distinct from confounding—A specific example 

is bias due to the inclusion of prevalent users, rather than new users, of an 

intervention

At intervention Risk of bias assessment is mainly distinct from assessments of randomised 

trials

Bias in classification of

interventions

Bias introduced by either differential or non-differential misclassification of 

intervention status

Non-differential misclassification is unrelated to the outcome and will usually 

bias the estimated effect of intervention towards the null

Differential misclassification occurs when misclassification of intervention 

status is related to the outcome or the risk of the outcome, and is likely to lead 

to bias

Post-intervention Risk of bias assessment has substantial overlap with assessments of 

randomised trials

Bias due to deviations

from intended

interventions

Bias that arises when there are systematic differences between experimental 

intervention and comparator groups in the care provided, which represent a 

deviation from the intended intervention(s)

Assessment of bias in this domain will depend on the type of effect of interest 

(either the effect of assignment to intervention or the effect of starting and 

adhering to intervention).

Bias due to missing

data

Bias that arises when later follow-up is missing for individuals initially 

included and followed (such as differential loss to follow-up that is affected by 

prognostic factors); bias due to exclusion of individuals with missing 

information about intervention status or other variables such as confounders

Bias in measurement of

outcomes

Bias introduced by either differential or non-differential errors in measurement 

of outcome data. Such bias can arise when outcome assessors are aware of 

intervention status, if different methods are used to assess outcomes in 

different intervention groups, or if measurement errors are related to 

intervention status or effects

Bias in selection of the

reported result

Selective reporting of results in a way that depends on the findings and 

prevents the estimate from being included in a meta-analysis (or other 

synthesis)
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APPENDIX E. QUALITY ASSESSMENT FOR INCLUDED RCT 

STUDIES

CHOLECYSTECTOMY 

Author, year Random 

sequence 

generation 

Allocation 

concealment

Blinding of 

participants 

and 

personnel

Blinding of 

outcome 

assessment

Incomplete 

outcome 

data

Selective 

reporting

Other 

sources 

of bias

Grochola, 

201913

Intraop       

Patient 

measures       

Heemskerk, 

201414       

Kudsi, 201715

      

Pietrabissa, 

201616       

= low risk of bias  = risk of bias  = unknown

INGUINAL HERNIA REPAIR

Author, 

year

Random 

sequence 

generation

Allocation 

concealment

Blinding of 

participants 

and 

personnel

Blinding of 

outcome 

assessment

Incomplete 

outcome 

data

Selective 

reporting

Other 

sources of 

bias

Prabhu 

202063

 



Singleblinded

  



Intuitive 

funded 

institutional 

research 

grant to 1st

author; 6 

authors 

received 

honoraria 

from 

Intuitive 

(including 

1st author)

 = low risk of bias  = risk of bias  = unknown
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APPENDIX F. QUALITY ASSESSMENT FOR INCLUDED OBSERVATIONAL STUDIES 

CHOLECYSTECTOMY

Author, year Confounding Selection bias Bias in 

measurement 

classification 

of 

interventions

Bias due to 

deviations 

from 

intended 

interventions

Bias due to 

missing 

data 

Bias in 

measurement 

of outcomes

Bias in 

selection of 

the reported 

result 

Other 

source of 

bias

Abel, 201932 Serious: not 

discussed

Serious: 

unknown how 

offered 

Low Low No 

information

Low Low n/a

Aggarwal, 

202022

Low: no serious 

demographic 

differences

Low: surgical 

method based 

on scheduled 

surgery date 

Low Low Low (short 

follow-up)

Low Low n/a

Albrecht, 

201717

Low: matched Moderate: 

unknown how 

offered

Low Low No 

information

Moderate: 

patient-reported 

pain scores

Low n/a 

Altieri, 201645 Low: propensity 

matching

Serious: 

unknown how 

offered, 

database

Low Low No 

information

Low Low n/a

Aragon, 

201444

Moderate: 

differences in 

weight

Serious, 

unknown how 

offered

Low Low Low: no 

missing data 

Low Low n/a 

Autin, 201539 Serious: not 

discussed 

Serious, 

unknown how 

offered

Low Low No 

information

Low Moderate n/a 
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Balachandran, 

201723

Moderate: sig 

differences in 

gender, BMI, 

comorbidities, 

previous 

abdominal 

surgeries and 

diagnosis 

Serious: 

unknown who 

was offered

robotic vs lap 

Low Low Low: 

excluded 

missing data 

Low Low n/a

Buzad, 201333 Moderate: sig 

differences in 

gender 

Serious for 

SILC: don’t 

know how they 

retrospectively 

chose cases 

Low for SSRC: 

consecutive 

cases in that 

time frame 

Low Low Low: no 

missing data 

Low Low

Calatayud, 

2012116

Low: similar 

groups

Serious: 

unknown who 

was offered 

robotic vs lap

Low Low No 

information

Low Low n/a 

Chung, 201524 Moderate: sig 

differences in 

age, BMI, 

elective nature, 

ASA 

classification, 

hypertension

Moderate: 

unknown 

whether it was 

consecutive or 

all cases, 

unclear how 

offered

Low Low Low: 

excluded 

missing data 

Low Low n/a

Eid, 202021 Serious: acuity of 

surgeries 

significantly diff 

between groups

Serious: 

unknown how 

offered 

Low Low Low (short 

follow-up) 

Low Low n/a

Farnsworth, 

201846

Moderate: 

significant 

differences in 

primary 

diagnoses 

Serious: 

prospectively 

collected ACS 

registry but 

don’t know 

Low Low No 

information

Low Low n/a 
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how people 

were offered 

Farukhi, 

201752

Serious: not 

discussed

Serious: 

unknown how 

offered 

Low Low No 

information

Low Low n/a 

Gonzalez, 

201334

Moderate: sig 

differences in 

age and ASA 

score 

Moderate: ALL 

robotic cases 

compared to 

first, 

consecutive 

166 lap cases, 

but don’t know 

how offered

Low Low Low: 

account for 

missing data 

Low Low n/a

Gustafson, 

201636

Moderate: BMI 

and prior abd 

surgeries 

significantly diff

Moderate: 

consecutive 

cases but don’t 

know how 

offered

Low Low Low: no 

missing data 

Moderate: pt 

reported 

outcomes

Low n/a 

Hagen, 201725 Low: patients 

matched by 

characteristic 

Moderate: 

don’t know 

how offered 

but matched

Low Low Low: no 

missing data

Low Low n/a

Hagen, 201730 Low: casematched 

analysis 

Moderate, 

unknown how 

offered 

Low Low No 

information

Low Low n/a 

Hawasli, 

201655

Moderate: age 

didn’t differ but 

didn’t discuss 

other sources of 

bias

Moderate: all 

cases in time 

period but 

didn’t discuss 

how offered 

Low Low No 

information

Low Low n/a 

Higgins, 

201761

Serious: don’t 

discuss

Serious: 

unknown who 

was offered 

robotic vs lap 

Low Low No 

information

Low Low n/a
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Jang, 201940 Serious: gender, 

age, BMI and 

ASA score 

differences

Serious, 

unknown how 

offered 

Low Low No 

information

Moderate: 

unknown who 

measured pain 

scale 

Low n/a 

Kaminski, 

201458

Moderate: shown 

but not analyzed 

differences in 

age, gender, 

race. Unsure of 

significant 

differences 

Serious: 

unknown who 

was offered 

robotic vs lap 

Low Low Low: 

excluded 

missing for 

outcomes of 

interest

Low Low n/a 

Kane, 202057 Low, propensitymatched Serious: 

unknown how 

offered 

Low Low No 

information

Low Low n/a

Khorgami, 

201949

Moderate: no 

differences, but 

lumped all 

surgeries 

together, no subanalysis of just 

cholecystectomy

Serious: 

unknown who 

was offered 

robotic vs lap

Low Low No 

information

Low Low n/a 

Lee, 201726 Moderate Moderate: 

unknown who 

was offered 

robotic vs lap

Low Low Low Moderate: 

patient-reported 

questionnaire 

Low n/a

Lee, 201841 Moderate: BMI, 

sex and 

indication 

differences

Serious: 

consecutively 

performed but 

unknown how 

offered 

Low Low No 

information

Low Low n/a 

Lee, 201927 Moderate: 

differences in 

age, ASA status, 

preop and 

pathologic 

diagnosis 

Moderate: 

patient decided 

robot vs lap

Low Low No 

information

Low Low n/a 
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Lescouflair, 

201442

Low: matched 

pts

Serious: 

consecutively 

performed but 

unknown how 

offered

Low Low No 

information

Moderate: pain 

measurements

Low n/a 

Li, 201728 Low: similar 

groups

Serious: 

unknown who 

was offered 

robotic vs lap

Low Low No 

information

Low Low n/a 

Main, 201718 Moderate: 

propensity 

matched 

analysis, but 

differences in 

indication

Serious: 

unknown who 

was offered 

robotic vs lap

Low Low No 

information

Low Low n/a

Mitko, 201620 Moderate: 

indication 

different

Serious: 

reviewed all 

performed but 

unknown how 

offered

Low Low No 

information

Low Low n/a 

Moore, 201643 Moderate: age 

different

Serious: 

consecutively 

performed but 

unknown how 

offered

Low Low No 

information

Low Low n/a 

Pokala, 201956 Serious: groups 

sig diff in age 

and race 

Serious: 

unknown how 

offered 

(database)

Low Low Low (short 

follow-up)

Low Low n/a

Rosemurgy, 

201550

Serious: don’t 

discuss

Serious: 

unknown who 

was offered 

robotic vs lap

Low Low No 

information

Low Low Didn’t 

report 

surgical 

indication/

diagnosis

Ross, 201453 Serious: no 

discussion

Serious: 

unknown how 

offered 

Low Low No 

information

Low Low n/a 
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Spinoglio, 

201237

Low, similar 

groups 

Low, 

consecutive 

cases that 

matched 

inclusion 

criteria 

matched to 25 

consecutive 

lap cases 

Low Low Low: no 

missing data 

Low Low n/a

Strosberg, 

201751

Moderate: 

differences in 

BMI, 

comorbidities 

and indication

Serious, 

unknown how 

offered

Low Low Low: no 

missing data 

Low Low n/a

Strosberg, 

201751

Serious: BMI, 

comorbidities, 

indication 

different

Serious: 

unknown how 

offered

Low Low No 

information

Low Low n/a 

Su, 201738 Low: similar 

groups

Serious, 

unknown how 

offered

Low Low Low: no 

missing data 

Moderate: 

unknown who 

measured pain 

scale 

Low n/a 

Teoh, 201731 Moderate: similar 

groups but not 

addressed what 

was measured

Serious: 

unknown how 

offered

Low Low No 

information

Moderate: 

unknown who 

measured pain 

scale 

Low n/a 

Wren, 201129 Low: average 

age and BMI not 

significantly 

different 

Moderate: 

robot offered to 

all who met 

inclusion/exclu

sion criteria 

and compared 

to previous 

sequential lap 

cases 

Low Low Low: no 

missing data 

Moderate: pain 

measurement

Moderate: 

excluded 1 

patient who 

had 

conversion

n/a 
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INGUINAL HERNIA REPAIR

Author, year Confounding Selection bias Bias in 

measurement 

classification of 

interventions

Bias due to 

deviations from 

intended 

interventions

Bias due to 

missing 

data

Bias in 

measurement of 

outcomes

Bias in 

selection of the 

reported result

Other source of 

bias

Abdelmoaty, 

201875

Serious: no 

baseline

characteristics 

reported

Low: database Low Low Low Low Low 1 author is a 

surgical proctor 

for Intuitive

AlMarqoozi, 

201971

Low: similar 

baseline 

characteristics 

and laterality 

except for age; 

non-propensity 

matched

Low: database Low Low Serious: 

Low 1-yr f/u 

(6-9%)

Low: 

complications

Moderate: QOL

Low 2 authors 

(including senior 

author) receive 

grants from 

Intuitive

Bittner, 201812 Moderate: 

cohorts differed 

by age, type of 

job, history of 

IHR, and use of 

preop pain meds; 

BMI not reported 

but propensity 

matched

Serious: random 

consumer sample 

with, only includes 

those with survey 

completion

Serious: recall 

bias due to study 

design

Low Serious: low 

survey 

response 

rate (6%)

Serious: narcotic 

use, RTW, pain

Low Study funded by 

Intuitive; 2 

authors 

(including senior 

author) 

employed by 

Intuitive; 1 

author receives 

consulting fees 

from Intuitive

Charles, 201868 Moderate: similar 

baseline 

characteristics 

except ASA; nonpropensity 

matched

Low: database Low Low Low Low: 

complications, 

OR times

Low 1 author with 

grant and travel 

expenses for 

educational 

course from 

Intuitive

Gamagami, 

201869

Low: similar 

baseline 

characteristics; 

propensity 

matched

Low: consecutive 

series

Low Low Low Low: 

complications

Moderate: pain 

not well-defined

Low Study sponsored 

by Intuitive; 

statistical 

analysis 

performed by 

Intuitive; all 

authors received 

research grants 

from Intuitive; 4 

authors received 
Robot-assisted Procedures in General Surgery Evidence Synthesis Program

109

Author, year Confounding Selection bias Bias in 

measurement 

classification of 

interventions

Bias due to 

deviations from 

intended 

interventions

Bias due to 

missing 

data

Bias in 

measurement of 

outcomes

Bias in 

selection of the 

reported result

Other source of 

bias

consulting and 

education fees 

from Intuitive

Holcomb, 

201984

Serious: most 

demographic 

data not 

displayed; nonpropensity 

matched

Low: database Low Low Low Low: 

complications

Low

Huerta, 201970 Serious: differs in 

laterality and 

hernia 

complexity; nonpropensity 

matched

Moderate: 

patients chosen 

by surgeon 

expertise

Low Low Low Low: 

inguinodynia, 

complications

Low

Janjua, 202077 Low: differences 

in age, gender, 

comorbidities, 

and laterality; 

propensity 

matched

Low: database Low Low Low Low: LOS Low

Kakaishvili, 

201872

Serious: baseline 

characteristics 

not specified, 

laterality differs; 

non-propensity 

matched

Serious: not 

specified if 

consecutive series

Low Low Low Low: OR times, 

complications

Moderate: pain

Low

Khoraki, 201978 Low: similar 

baseline 

characteristics; 

non-propensity 

matched

Low Low Low Low Low: 

complications

Low

Knott, 201780 Serious: not 

propensity 

matched, 

adjusted for 

patient 

Low: database Low Low Moderate: 

unknown 

follow-up

Low Low
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Author, year Confounding Selection bias Bias in 

measurement 

classification of 

interventions

Bias due to 

deviations from 

intended 

interventions

Bias due to 

missing 

data

Bias in 

measurement of 

outcomes

Bias in 

selection of the 

reported result

Other source of 

bias

characteristics 

but not displayed

Kolachalam, 

201766

Low: similar 

characteristics, 

propensity 

matched

Low: consecutive 

series for robotic 

group

Moderate: open 

group patients 

prior to study 

initiation

Low Low Low Low Low Study sponsored 

by Intuitive; 

statistical 

analysis 

performed by 

Intuitive 

biostatistician; 

all authors 

received 

research grants 

from Intuitive; 4 

authors received 

consulting and 

education fees 

from Intuitive

Kosturakis, 

201867

Serious: baseline 

characteristics 

differ in hernia 

laterality and 

ASA; nonpropensity 

matched

Low: consecutive 

series

Low Low Moderate: 

unknown 

follow-up

Low Low

Kudsi, 201774 Serious: similar 

baseline 

characteristics 

and laterality 

except gender 

and ASA; nonpropensity 

matched

Low: consecutive 

series

Low Low Moderate: 

missing 

some data 

in robot 

group at f/u

Low: 

complications, 

inguinodynia

Low 1st author is 

consultant for 

Intuitive

Lammers, 

201983

Serious: similar 

baseline 

characteristics 

but not reported; 

non-propensity 

matched

Low: consecutive 

series

Low Low Low Low: OR times, 

complications

Moderate: 

spread not 

reported
Robot-assisted Procedures in General Surgery Evidence Synthesis Program

111

Author, year Confounding Selection bias Bias in 

measurement 

classification of 

interventions

Bias due to 

deviations from 

intended 

interventions

Bias due to 

missing 

data

Bias in 

measurement of 

outcomes

Bias in 

selection of the 

reported result

Other source of 

bias

Macias, 201781 Serious: baseline 

characteristics 

and laterality not 

reported

Serious: not 

specified if 

consecutive series

Low Low Moderate: 

unknown 

follow-up

Low: OR times, 

inguinodynia

Moderate: 

limited 

perioperative 

and long-term 

outcomes 

reported

Muysoms, 

201873

Moderate: similar 

patient 

characteristics 

except baseline 

QOL, laterality 

analyzed in 

subgroups; nonpropensity 

matched

Low: consecutive 

series for robot

Moderate: lap 

patients from 

previously 

published studies

Low Low Low Low: OR times, 

complications

Moderate:

QOL/pain

Low 1st author 

receives 

consultant fees 

from Intuitive

Pokala, 201982 Serious: baseline 

characteristics 

not completely 

reported; robot 

patients more 

male; nonpropensity 

matched

Moderate: 

database, severe 

severity excluded

Low Low Low Low: 

complications, 

pain

Low

Sheldon, 

201979

Moderate: similar 

baseline 

characteristics 

except for 

laterality, other 

characteristics 

not reported; nonpropensity 

matched

Serious: 

institutional data, 

not stated if 

consecutive 

series; patients 

with intraoperative 

conversions of 

approach 

excluded

Low Low Low Low: narcotic use Low

Switzer, 201964 Serious: similar 

baseline 

demographics, 

baseline QOL 

scores, laterality, 

but not explicitly 

reported; nonSerious: 

database; 

excluded patients 

without 6-mo 

EuraHS

Low Low Low Low: 

complications, 

readmissions, 

recurrences 

Moderate: 

EuraHS QOL

Moderate: 

complications 

not specified
Robot-assisted Procedures in General Surgery Evidence Synthesis Program

112

Author, year Confounding Selection bias Bias in 

measurement 

classification of 

interventions

Bias due to 

deviations from 

intended 

interventions

Bias due to 

missing 

data

Bias in 

measurement of 

outcomes

Bias in 

selection of the 

reported result

Other source of 

bias

propensity 

matched

Waite, 201665 Low: similar 

baseline 

characteristics, 

laterality

Low: consecutive 

series

Low Low Low Low: OR times

Moderate: pain 

scale 

Low 1 author became 

a consultant for 

Intuitive 

following 

preparation of 

manuscript

Zayan, 201976 Serious: differ by 

gender, smoking 

status, comorbidities, and 

laterality; nonpropensity 

matched

Serious: not 

stated if 

consecutive 

series, selected 

based on 

availability to 

complete 1-yr f/u 

survey

Low Low Low Low: LOS, OR 

times, 

complications

Moderate: QOL

Moderate: 

limited reporting 

of complications

VENTRAL HERNIA REPAIR

Author, year Confounding Selection 

bias

Bias in 

measurement 

classification 

of 

interventions

Bias due to 

deviations 

from intended 

interventions

Bias due 

to missing 

data

Bias in 

measurement 

of outcomes

Bias in 

selection of the 

reported result

Other source of 

bias

Altieri, 201899 Moderate: differences 

in ethnicity, gender, 

BMI; propensity 

matched but 

characteristics not 

reported

Low: 

database

Low Low Low Low: 

complications

Moderate: 

matched 

outcomes poorly 

reported and 

inconsistent with 

tables

Armijo, 2018104 Moderate: similar 

characteristics except 

gender and comorbidities; nonpropensity matched

Low: 

database

Low Low Low Low: narcotic 

use, 

complications

Low

Bittner, 201886 Serious: differences in 

co-morbidities, 

smoking status, 

Low Low Low Low Low: 

complications

Moderate: no 

data on 

1st author is 

consultant for 

Intuitive
Robot-assisted Procedures in General Surgery Evidence Synthesis Program

113

Author, year Confounding Selection 

bias

Bias in 

measurement 

classification 

of 

interventions

Bias due to 

deviations 

from intended 

interventions

Bias due 

to missing 

data

Bias in 

measurement 

of outcomes

Bias in 

selection of the 

reported result

Other source of 

bias

gender, hernia size; 

non-propensity 

matched

recurrences at 

90 days

Carbonell, 

201890

Low: similar 

characteristics, 

including proportion of 

TARs performed; 

propensity matched

Low: 

database

Low Low Low Low: 

complications

Low 6 authors 

(including 1st

author) received 

honoraria from 

Intuitive; 2 

authors received 

educational 

funds from 

Intuitive

Chen, 2016100 Moderate: similar 

characteristics except 

for gender; nonpropensity matched

Low Low Low Low Low: 

complications, 

recurrence 

Low

Coakley, 201798 Low: similar baseline 

characteristics; nonpropensity matched

Low: 

database

Low Low Low Low: 

complications

Low

Gonzalez, 

201595

Low: similar baseline 

characteristics; nonpropensity matched

Low Low Low Moderate: 

unknown 

follow-up

Low: 

complications, 

recurrence

Low

GuzmanPruneda, 

202091

Serious: large 

difference in gender, 

smoking status, hernia 

size; non-propensity 

matched

Low: 

database

Low Low Low Low: 

complications, 

recurrence 

Moderate: QOL

Low Operative 

techniques (eg

drain placement) 

were significantly 

different between 

comparison 

groups

Khorgami, 

201894

Serious: unable to 

assess characteristics, 

as data was pooled for 

multiple procedures; 

non-propensity 

matched

Low: 

database

Low Low Low Low: LOS Serious: no 

other outcomes 

besides LOS
Robot-assisted Procedures in General Surgery Evidence Synthesis Program

114

Author, year Confounding Selection 

bias

Bias in 

measurement 

classification 

of 

interventions

Bias due to 

deviations 

from intended 

interventions

Bias due 

to missing 

data

Bias in 

measurement 

of outcomes

Bias in 

selection of the 

reported result

Other source of 

bias

Lu, 201993 Moderate: similar 

baseline characteristics 

except for gender and 

co-morbidities; nonpropensity matched

Low Low Low Serious: 

large 

difference 

in 1-year 

follow-up 

rates 

between 

groups

Low: 

complications, 

recurrence 

Low Senior author 

has received 

honoraria for 

speaking 

engagements 

and consulting 

for Intuitive

Martin-delCampo, 201887Low: similar baseline 

characteristics except 

ASA; propensity 

matched for hernia size

Low Low Low Low Low: 

complications

Low 2 authors are 

consultants for 

Intuitive

Mudyanadzo, 

2020

Serious: baseline 

characteristics not 

reported; nonpropensity matched

Serious: 

institutional 

data, not 

stated if 

consecutive 

series

Low Low Low Low: pain, 

narcotic use

Low

Nguyen, 201788 Moderate: similar 

characteristics except 

hernia size; nonpropensity matched

Serious: 

institutional 

data, not 

stated if 

consecutive 

series

Low Low Low Low: 

complications

Low

Prabhu, 201796 Low: similar baseline 

characteristics; 

propensity matched

Low: 

database

Low Low Low Low: 

complications

Low 1st and senior 

authors receive 

grant money 

from Intuitive

Roberts, 201992 Serious: significantly 

different hernia defect 

size, other baseline 

characteristics not 

reported; nonpropensity matched

Low: 

database

Low Low Low Low: pain, 

complications

Low

Song, 2017103 Moderate: 

characteristics not 

Low: 

database

Low Low Low Low: 

complications, 

narcotic use

Low
Robot-assisted Procedures in General Surgery Evidence Synthesis Program

115

Author, year Confounding Selection 

bias

Bias in 

measurement 

classification 

of 

interventions

Bias due to 

deviations 

from intended 

interventions

Bias due 

to missing 

data

Bias in 

measurement 

of outcomes

Bias in 

selection of the 

reported result

Other source of 

bias

explicitly reported; 

propensity matched

Switzer, 201789 Moderate: similar age, 

gender, hernia size, 

other characteristics 

not explicitly reported; 

propensity matched

Low: 

database

Low Low Moderate: 

unknown 

follow-up

Low: 

complications, 

recurrence 

Moderate: QOL

Moderate: 

complications 

outcomes not 

defined or 

reported

Walker, 201897 Moderate: similar 

baseline characteristics 

except gender; 

propensity matched 

except for gender, and 

matched 

characteristics not 

reported

Serious: 

institutional 

data, not 

stated if 

consecutive 

series

Low Low Moderate: 

unknown 

follow-up

Low: 

complications, 

recurrence 

Moderate: 

matched 

outcomes only 

selectively 

reported

2 authors 

(including senior 

author) receive 

honoraria to 

proctor for 

Intuitive

Warren, 2016101 Serious: similar 

characteristics except 

gender, recurrent 

hernia, and whether 

TAR performed 

concurrently; nonpropensity matched

Low: 

database

Low Low Low Low: narcotic 

use, 

complications

Low 1st and senior 

authors are 

speakers for 

Intuitive

Zayan, 201976 Serious: difference in 

gender, BMI, smoking 

status, baseline QOL; 

non-propensity 

matched

Serious: 

institutional 

data, not 

stated if 

consecutive 

series

Low Low Moderate: 

unknown 

follow-up

Low: recurrence

Moderate: QOL

Moderate: no 

outcomes 

relating to other

complications
Evidence Synthesis Program

116

Robot-assisted Procedures in General Surgery

APPENDIX G. EVIDENCE TABLES 

CHOLECYSTECTOMY 

Demographics and Pre-operative Factors 

Author 

Year 

Population 

Study Design

US (y/n) 

VA (y/n) 

# Institutions/ 

Surgeons

Propensity 

Matching

Patient Characteristics Preop

N

Age, mean yr (SD) 

Race/Ethnicity 

 NH-White, % 

 NH-Black, % 

 NH-Asian, % 

 Hispanic, % 

Male, % 

BMI, mean (SD) 

ASA class, mean (SD) 

Diabetes, % 

Indication for surgery 

 Acute Chole, N (%) 

 Symptomatic Cholelithiasis, N (%) (ie, biliary colic, sludge, chronic cholecystitis) 

 Other, N (%) (ie, cancer, polyps, choledocholithiasis, gallstone pancreatitis, etc) 

Elective operation, %

Total Single-Port 

Robot 

Single-Port 

Lap

Multi-Port 

Robot 

Multi-Port Lap Unspecified 

Robot

Unspecified 

Lap

Specified 

combined 

single and 

multi- port 

Robot

Specified 

combined 

single and

multi-port 

Lap

Abel S

201932

Retrospective 

cohort 

Y 

N

NR/NR No N: 584 N: 296

BMI: 32 

N: 288

BMI: 31 

Aggarwal R

202022

Retrospective 

cohort 

N 

N 

Single 

institution/ 

Single 

surgeon 

No N: 40 N: 20 

Age: 45.9 (13) 

Male: 3 (15%) 

BMI: 28.5 (4.4) 

ASA 1: 9 (45%) 

ASA 2: 10 

(50%) 

ASA 3: 1 (5%) 

Cholecyst: 3 

(15%) 

Biliary colic: 16 

(80%) 

GB polyp: 1 

(5.0%) 

Previous 

abdominal 

N: 20 

Age: 48.4 (12.2) 

Male: 3 (15%) 

BMI: 31.3 (6.2) 

ASA 1: 8 (40%)

ASA 2: 12 (60%) 

ASA 3: 0 (0%) 

Cholecyst: 7 

(35%) 

Biliary colic: 13 

(65%) 

GB polyp: 0 (0%) 

Previous 

abdominal 

surgery: 3 (15%) 
Robot-assisted Procedures in General Surgery Evidence Synthesis Program

117

surgery: 7 

(35%)

Albrecht R 

201717

Retrospective 

(matched-pair 

analysis) 

N 

N 

Multiinstitutional N: 70 N: 35

Age: 55.5 

(17.3) 

Men: 13 

(37.1%) 

BMI: 28.3 (5.7) 

ASA I: 10 

(28.6%) 

ASA II: 22 

(62.9%) 

ASA III: 3 

(8.6%) 

Elective: 32 

(91.4%) 

N: 35 

56.9 (16.7) 

Men: 13 (37.1%) 

30.0 (5.2) 

BMI >30: 14 

ASA I: 12 

(34.3%) 

ASAII: 19 

(54.3%) 

ASA III: 4 

Elective: 30 

(85.7%) 

Altieri MS 

201645

SPARCS 

database 

Prospective 

cohort 

Y 

N 

Not reported Yes N: 110052 N: 186

NH-W: 

69.35% 

NH-Black: 

6.99% 

NH-Asian: 

2.69% 

Hispanic: 

12.37% 

Male: 34.41% 

Diabetes: 

17.74% 

N: 109,866

NH-W: 

58.54% 

NH- Black: 

10.95% 

NH-Asian: 

2.89% 

Hispanic: 

18.64% 

Male: 35.42% 

Diabetes: 

16.48% 

Aragon RJ 

201444

Prospective 

observational 

study 

Y 

N 

1 institution No N: 330

Age: 45 (14) 

Male: 27% 

Weight: 88.3 

(24.1) 

Sympt

cholelithiasis: 

79.1% 

Acute cholecyst: 

13.64% 

Other: 7.3% 

N: 132 

Weight: 86.2 

(23.6) 

N: 36

Weight: 74.4 

(15.8) 

N; 162 

Weight: 93.1 

(24.7) 

Autin RL 

201539

Retrospective 

analysis 

Y 

N

1 institution No N: 54 N: 27 N: 27 

Balachandran 

B 

201723

Retrospective 

cohort 

1 Surgeon, 1 

Institution 

No N: 678

Age: 54.8 (18.6) 

Male: 209 

(30.8%) 

BMI: 29.6 (6.9) 

ASA I: 21% 

N: 415

Age: 54.1 (18.7) 

Male: 111 (26.7%) 

BMI: 29 (6.1) 

ASA I: 21.5% 

ASA II: 54.8%

N: 263

Age: 55.8 (18.4) 

Male: 98 (37.3%) 

BMI: 30.5 (7.8) 

ASA I: 20.4% 

ASA II: 47.8% 
Robot-assisted Procedures in General Surgery Evidence Synthesis Program

118

Y

N 

ASA II: 51.9% 

ASA III: 25.1% 

ASA IV: 0%

ASA V: 2.0% 

Diabetes: 112 

(16.5%) 

Acute cholecyst: 

173 (25.5%) 

Chronic 

cholecyst: 505 

(74.5%) 

ASA III: 21.8% 

ASA IV: 0%

ASA V: 1.9% 

Diabetes: 61 

(14.9%) 

Acute cholecyst: 

76 (18.3%) 

Chronic cholecyst: 

339 (81.7%) 

ASA III: 29.6% 

ASA IV: 0%

ASA V: 2.2% 

Diabetes: 51 

(19.4%) 

Acute cholecyst: 

97 (36.9%) 

Chronic 

cholecyst: 166 

(63.1%) 

Buzad FA 

201333

Prospective 

cohort with 

historically 

(retrospective) 

matched pairs 

Y 

N 

1 institution/ 1 

surgeon 

No N: 30 N: 20

Age: 47.8 (14.9) 

NH White: 70% 

(14) 

Hispanic: 25% (5) 

Other: 5% (1) 

Male: 35% (7) 

BMI: 27.1 (4.7) 

ASA I: 20% (4) 

ASA II: 80% (16) 

Acute cholecyst: 

10% (2)

Other: 18 (90%) 

N: 10

Age: 43.3 

(13.7) 

NH White: 80% 

(8)

Hispanic: 20% 

(2) 

Other: 0 

Males: 0% (0) 

BMI: 28.4 (6.2) 

ASA I: 50% (5) 

ASA II: 50% (5) 

Acute 

cholecyst: 0 

Other: 10 

(100%)

Calatayud D 

2012 116

Retrospective 

analysis 

Y 

N

1 Institution No N: 187 N: 119

Age: 43.67 

Male: 22% 

BMI: 32.8 

N: 68

Age: 44.6 

Male: 23.5% 

BMI: 32.8 

Chung PJ 

201524

Retrospective 

cohort 

Y 

N 

1 Institution/

N/R 

No N: 140 N: 70

Age: 40.3 (15.2) 

White: 15% 

Black: 53% 

Asian-Pacific: 

2.0% 

Male: 14.3% (10) 

BMI: 29.5 (6.2) 

ASA I: 11.4% (8) 

ASA II: 65.7% 

(46) 

ASA III: 20% (14) 

ASA IV: 0 

Diabetes: 10% 

Elective: 46% 

N: 70

Age: 47.6 (17.2) 

White: 59% 

Black: 9% 

Asian-Pacific: 

1% 

Male: 18.6% (13) 

BMI: 32.4 (7.4) 

ASA I: 4.3% (3) 

ASA II: 52.9% 

(37) 

ASA III: 41.4% 

(29) 

ASA IV: 1.4% (1) 

Diabetes: 19% 

Elective: 20% 

Eid JJ

202021

Retrospective 

cohort

Single 

institution/ 

Multiple 

surgeons 

No N: 90 N: 20 

Age: 44.1 

(15.4) 

Caucasian: 5 

N: 70 

Age: 42.3 (17) 

Caucasian: 10 

(14.3%)
Robot-assisted Procedures in General Surgery Evidence Synthesis Program

119

Y

N 

(25%)

AfricanAmerican: 14 

(70%) 

Other/ Decline: 

1 (5%) 

Male: 2 (10%) 

BMI: 35.7 (9.4) 

ASA I: 2 (10%) 

ASA II: 10 

(50%) 

ASA III: 8 

(40%) 

ASA IV: 0 (0%)

Diabetes: 2 

(10%) 

Acute 

cholecyst: 5 

(25%) 

Biliary colic: 12 

(60%) 

Choledocholithi

asis: 3 (15%) 

Biliary 

dyskinesia: 0 

(0%)

Outpatient: 19 

(95%) 

ER admission: 

1 (5%)

AfricanAmerican: 58 

(82.9%) 

Other/ Decline: 2 

(2.9%) 

Male: 10 (14.3%) 

BMI: 34.3 (8.2) 

ASA I: 6 (8.6%) 

ASA II: 44 

(62.9%) 

ASA III: 20 

(28.6%) 

ASA IV: 0 (0%) 

Diabetes: 7 

(10%) 

Acute cholecyst: 

26 (37.1%) 

Biliary colic: 30 

(42.9%) 

Choledocholithia

sis: 13 (18.6%) 

Biliary 

dyskinesia: 1 

(1.4%) 

Outpatient: 12 

(17.1%) 

ER admission: 

58 (82.9%) 

Farnsworth J 

201846

Observational 

(prospectively 

collected 

registry) 

Y 

N

1 institution/ 2 

surgeons 

No N: 51 N: 14 N: 37 

Farukhi MA 

201752

Case control 

retrospective 

analysis 

Y 

N

1 institution No N: 139 N: 69 

Morbidly 

obese: 42 

N: 70 

Morbidly 

obese: 19 

Gonzalez AM 

201334

Retrospective 

cohort 

Y 

N 

1 institution (3 

hospitals)/ 3 

surgeons 

No N: 498 N: 166

Age: 51.6 (15.9) 

Male: 21.1% (35) 

BMI: 29.4 (6.2) 

Mean ASA: 1.84 

(0.73) 

Acute cholecyst: 

12% (20)

N: 169

Age: 44.5 

(14.3) 

Male: 23.7% 

(40) 

BMI: 29.1 (5.6) 

Mean ASA: 

1.72 
Robot-assisted Procedures in General Surgery Evidence Synthesis Program

120

Sympt

cholelithiasis: 

76.5% (127) 

Other: 19 (11.4%) 

(0.64)Acute 

cholecyst: 6.5% 

(11) 

Sympt

cholelithiasis: 

78.7% (133) 

Other: 11 

(6.5%)

Grochola LF 

201913

RCT 

No 

(Switzerland) 

No 

1 institution/ 3 

surgeons 

No N: 60 N: 30 

Age: 52.4 (26-82) 

Race/ethnicity: 

N/R 

Male: 10 (33.3%) 

BMI: 27.3 (3.9) 

ASA class: N/R 

Diabetes: n/R 

Sympt

Cholelithiasis: 

96.7% (29) 

Other: 3.3% (1) 

Elective: 100% 

N: 30 

Age: 51.5 (30-

78) 

Race/ ethnicity: 

N/R 

Male: 14 

(46.7%) 

BMI: 27.3 (4.2) 

ASA class: N/R 

Diabetes: N/R 

Sympt

cholelithiasis: 

96.7% (29) 

Other 3.3% (1)

Elective: 100% 

Gustafon M

201636

Observational 

(retrospective 

analysis of 

prospective 

database) 

Y 

N 

1 institution/ 1 

surgeon 

No N: 82 N: 38

Age: 48 (14) 

Race: N/R 

Male: 21% 

BMI: 30 (5) 

ASA mean: 1.5 

(1-3) 

Diabetes: N/R 

Indication: N/R 

Elective: N/R

N: 44

Age: 45 (15) 

Race: n/r 

Male: 23% 

BMI: 26 (4) 

ASA mean: 1.6 

(1-3) 

Diabetes: n/r 

Indication: n/r 

Elective: n/r

Hagen ME

201825

Retrospective 

cohort, 

matched pair 

N 

N 

1 Institution Yes N: 198 N: 99

Age: 47.4 (12.6) 

Race: N/R 

Male: 27.3% (27) 

BMI: 26.2 (4.2) 

ASA I and II: 96% 

(95) 

III and IV: 4% (4) 

Diabetes: N/R 

Sympt

cholelithiasis: 

100% 

Elective: N/R 

N: 99

Age: 47 (14) 

Race: N/R 

Male: 27.3% (27) 

BMI: 26.3 (4.9) 

ASA I and II: 

96% (95) 

ASA III and IV: 

4% (4)

Diabetes: N/R 

Sympt

cholelithiasis: 

100% 

Elective: N/R

Hagen ME 

2018 30

Retrospective, 

case-matched 

analysis 

Not reported No N: 156 N: 78 N: 78
Robot-assisted Procedures in General Surgery Evidence Synthesis Program

121

Y

N

Hawasli A

201655

Observational 

(retrospective) 

Y 

N

1 institution/

14 surgeons 

No N: 246

Age: 45.4 (17.1) 

Male: 15.9% (39) 

N: 26 (14 

single port 

robot - 

53.8%)) 

Age: 46.2 

(11.2)

N: 220 (8 

single port 

lap - 3.6%) 

Age: 45.3 

(17.6) 

Heemskerk J 

201414

Prospective 

Randomized 

Trial

N 

N

1 Institution/ 2 

surgeons 

No N: 22 N: 11 N: 11

Higgins RM 

201761

Surgical 

Profitability 

Compass 

Procedure 

Cost Manager 

System 

Database 

Retrospective 

analysis 

Y 

N

Not reported No N: 381 N: 38 N: 343

Jang EJ 

201940

Retrospective 

analysis 

N 

N 

2 institutions/

2 surgeons (1 

for SILC and 1 

for RSSC) 

No N: 117

Males: 58 

(49.6%) 

ASA 1: 36 

(30.8%) 

ASA 2: 63 

(53.8%) 

ASA 3: 18 

(15.4%) 

Acute cholecyst: 

4 (3.4%) 

Sympt

cholelithiasis: 86 

(73.5%) 

Other: 27 

(23.1%) 

N: 39 

Age: 42.03 

(10.72) 

Male: 14 (35.9%) 

BMI: 28.17 

(2.972) 

ASA 1: 20 

(51.3%) 

ASA 2: 15 

(38.5%) 

ASA 3: 4 (10.3%) 

Acute cholecyst: 0 

Sympt

cholelithiasis: 32 

(82.1%) 

Other: 7 (17.9%) 

N: 78

Age: 49.76 

(12.949) 

Male: 44 

(56.4%) 

BMI: 27.17 

(2.278) 

ASA 1: 16 

(20.5%) 

ASA 2: 48 

(615%) 

ASA 3: 14 

(17.9%) 

Acute 

cholecyst: 4 

(5.1%) 

Sympt

cholelithiasis: 

54 (69.2%) 

Other: 20 

(25.6%)

Kaminski JP

201458

NIS dataset 

Not reported No N: 735,537 2010

N: 524 

Available 

2010

N: 362,971 

Available 
Robot-assisted Procedures in General Surgery Evidence Synthesis Program

122

Retrospective 

analysis 

Y 

N 

observations: 

451 

Age: 53.3 

Male: 26.4% 

(119) 

Caucasian: 

79.6% (359) 

African 

American: 

10% (45) 

Hispanic: 7% 

(31) 

Asian: 1.1% 

(5)

Native 

American: 0% 

(0)

Others: 2.3% 

(10) 

DM (with and 

w/o 

complication): 

13.4% 

Acute 

cholecyst: 

7.1% 

2011 

N: 1084 

Available 

observations: 

991 

Age: 55.8 

Male: 35.3% 

(350) 

Caucasian: 

68.2% (676) 

African 

American: 

11.9% (118) 

Hispanic: 

14.3% (141) 

Asian: 1.9% 

(19) 

Native 

American: 

0.5% (5) 

Others: 1.8% 

(18) 

DM (w/ or w/o 

complication): 

21.5% 

Acute 

observations: 

327,803 

Age: 49.3 

Male: 32.9% 

(107,941) 

Caucasian: 

65.3% 

(214,074) 

African 

American: 

10.3% 

(33,656) 

Hispanic: 

18.6% 

(60,848) 

Asian: 2.2% 

(7,366) 

Native 

American: 

0.8% (2,501) 

Others: 2.9% 

(9,358) 

DM (w/ or w/o 

complication): 

16.8% 

Acute 

cholecyst: 

39.2% 

2011 

N: 370,958 

Available 

observations: 

338,702 

Age: 51.1 

Male: 34.1% 

(115,406) 

Caucasian: 

63.7% 

(215,916) 

African 

American: 

10.1% 

(34,072) 

Hispanic: 

20.2% 

(68,541) 

Asian: 2.0% 

(6,685) 

Native 

American: 

0.7% (2,254) 

Others: 3.3% 

(11,234)
Robot-assisted Procedures in General Surgery Evidence Synthesis Program

123

cholecyst: 

10.8% 

DM (w/ or w/o 

complication): 

17.6% 

Acute 

cholecyst: 

41.7% 

Kane WJ

202057

Retrospective 

Cohort 

Y 

N 

Single 

institution/ 

Multiple 

surgeons 

Yes N: 1066 N: 106 

Age: 41.5 (30-

56)* 

White: 80 

(75.5%) 

Male: 30 

(28.3%) 

BMI: 30.1 

(26.5-36.4)* 

Diabetes: 7 

(6.6%)

N: 1060 

Age: 43 (30-

58)* 

White: 806 

(76%) 

Male: 313 

(29.5%) 

BMI: 30.2 

(26.5-35.2)* 

Diabetes: 79 

(7.5%)

Khorgami Z

201949

NIS 

Retrospective 

analysis 

Y 

N

Not reported No N: 70,673 N: 1,271 N: 69,402 

Kudsi OY 

201715

Randomized 

controlled trial 

Mixed (7 

institutions in 

US, 1 in 

Greece) 

N 

8 institutions/

10 surgeons 

N: 136 N: 83 

Age: 46.8 (15.5) 

Caucasian: 46 

(55%) 

African-American: 

9 (11%) 

Asian: 3 (4%) 

Hispanic: 25 

(30%) 

Male: 18 (21%) 

BMI: 30.4 (6.5) 

ASA I: 17 (20%) 

ASA II: 52 (63%) 

ASA III: 13 (16%) 

ASA IV: 1 (1%) 

DM: 5 (6%) 

Acute cholecyst: 0

Sympt

cholelithiasis: 69 

(83.1%) 

Other: 14 (16.8%) 

Elective: 100% 

N: 53

46.5 (17.3) 

Caucasian: 29 

(55%) 

AfricanAmerican: 7 

(13%) 

Asian: 0 (0%) 

Hispanic: 17 

(32%) 

Male: 4 (7%) 

BMI: 31.7 (6.7) 

ASA I: 11 (21%) 

ASA II: 34 (64%) 

ASA III: 8 (15%) 

ASA IV: 0 (0%) 

DM: 4 (8%) 

Acute cholecyst: 

0 

Sympt 

cholelithiasis: 47 

(86.7%) 

Other: 7 (13.2%) 

Elective: 100%

Lee EK 

201726

Retrospective 

analysis 

No N: 120

Male: 42.5% 

N: 60

Age: 42.53 (9.92) 

Male: 28 (46.7%) 

BMI: 24.45 (3.63) 

ASA I: 37 (61.7%)

N: 60 

Age: 46.58 

(12.44) 

Male: 23 (38.3%) 

BMI: 24.67 
Robot-assisted Procedures in General Surgery Evidence Synthesis Program

124

N

N 

ASA II: 23 

(38.3%) 

Acute cholecyst: 0 

(0%) 

Sympt

cholelithiasis: 13 

(15.1%) 

Other: 73 (84.9%) 

(4.01)

ASA I: 74 

(61.7%) 

ASA II: 46 

(38.3%) 

Acute cholecyst: 

7 (4%) 

Sympt

cholelithiasis: 48 

(27.1%) 

Other: 122 

(68.9%)

Lee JH 201841

Retrospective 

analysis 

Y 

N 

1 institution/ 2 

surgeons 

No N: 630 N: 520

Age: 48 (10.1) 

Male: 135 (25.9%)

BMI: 23.9 (3.6) 

Sympt

cholelithiasis: 

72.2% 

N: 110

Age: 36.4 (9.6) 

Male: 8 (7.3%) 

BMI: 21.8 (2.4) 

Sympt

cholelithiasis: 

67.4% 

Lee SR

201927

Retrospective 

analysis 

N 

N 

1 institution/ 1 

surgeon 

No N: 121

Age: 46.8 

(11.64) 

Male: 52 (51.2%) 

BMI: 25 (3.59) 

ASA 1: 85 

(70.2%) 

ASA 2: 36 

(29.8%) 

Acute cholecyst: 

0 (0%) 

Sympt

cholelithiasis: 69 

(57.0%) 

Other: 38 

(43.0%) 

N: 61

Age: 42.69 (8.95) 

Male: 34 (55.7%) 

BMI: 24.78 (3.62) 

ASA 1: 38 

(62.3%) 

ASA 2: 23 

(37.7%) 

Acute cholecyst: 0 

(0%)

Sympt

cholelithiasis: 23 

(37.7%) 

Other: 38 (62.3%) 

N: 60 

Age: 50.33 

(12.82) 

Male: 28 (46.7%) 

BMI: 25.23 

(3.57) 

ASA 1: 47 

(78.3%) 

ASA 2: 13 

(21.7%) 

Acute cholecyst: 

0 (0%) 

Sympt

cholelithiasis: 46 

(76.7%) 

Other: 14 

(23.4%)

Lescouflair T 

201442

Retrospective 

review of 

prospectively 

maintained 

database 

Y 

N

1 institution/ 1 

surgeons 

N: 82 N: 41 N; 41 

Li YP

201728

Retrospective 

analysis 

N 

N 

1 institution/ 2 

surgeons 

No N: 445 N: 78

Age: 56.69 

(13.35) 

Male: 37 (48.3%) 

BMI: 24.17 (3.01) 

Sympt

cholelithiasis: 53 

(68%)

N: 367 

Age: 51.44 

(14.11) 

Male: 161 

(43.9%) 

BMI: 25.63 

(4.13) 

Sympt
Robot-assisted Procedures in General Surgery Evidence Synthesis Program

125

Acute cholecyst: 

17 (21.8%) 

Other: 8 (10.3%) 

cholelithiasis: 

235 (64%) 

Acute cholecyst: 

91 (24.8%) 

Other: 41 

(11.2%)

Main WPL

201718

Retrospective 

analysis 

Y 

N 

1 institution Yes N: 1133 N: 179

Age: 47.19 

(14.92) 

BMI: 38.85 

(7.29) 

ASA I: 10 

ASA II: 107 

ASA III: 58 

ASA IV: 4 

Before 

propensity score 

matching 

N: 1133 

Age: 46.38 

(16.41) 

BMI: 36.89 

(5.95) 

ASA I: 46 

ASA II: 520 

ASA III: 373 

ASA IV: 15 

After Propensity 

Score Matching 

N: 358 

Age: 45.91 

(15.12) 

BMI: 38.75 

(6.72) 

ASA I: 25 

ASA II: 216 

ASA III: 112 

ASA IV: 5 

Mitko J 

201620

Retrospective 

analysis 

Y 

N

1 institution No N: 1133 N: 179

BMI: 38.8 

Acute 

cholecyst: 6% 

Chronic 

cholecyst: 93% 

N: 954 

BMI: 36.8 

Acute cholecyst: 

11.7% 

Chronic 

cholecyst: 87% 

Moore MD 

201643

Retrospective 

analysis 

Y 

N 

1 institution/ 2 

surgeons 

No N: 50 N: 21

Age: 47 (15) 

Male: 5 (24%) 

BMI: 26 (3) 

ASA 1 : 2 (9.5%) 

ASA 2: 14 

(66.7%) 

ASA 3 or higher: 5 

(23.8%) 

Acute cholecyst: 2 

(9.5%) 

Sympt

cholelithiasis: 17 

(80.9%) 

Other: 2 (9.5%) 

N: 29 

Age: 37 (15) 

Male: 3 (10%) 

BMI: 28 (6) 

ASA 1: 4 

(13.8%) 

ASA 2: 22 

(75.9%) 

ASA 3 or 

higher: 3 

(10.3%) 

Acute 

cholecyst: 5 

(17.2%) 

Sympt

cholelithiasis: 

21 (72.4%)
Robot-assisted Procedures in General Surgery Evidence Synthesis Program

126

Other: 3 

(2.77%)

Pietrabissa A

201616

Prospective, 

randomized, 

double-blind 

trial 

N 

N

1 institution/ 4 

surgeons 

No N: 60 N: 30 N: 30 

Pokala B

201956

Retrospective 

analysis of 

Vizient 

database 

Y 

N 

Multiinstitution/ 

multisurgeons 

No N: 91849 N: 1971

Age 18-30yrs: 

215 (10.9%) 

Age 31-50yrs: 

699 (35.5%) 

Age: 51-64yrs: 

531 (26.9%) 

Age ≧ 65: 526 

(26.7%) 

White: 1317 

(67.9%) 

Black: 334 

(17.2%) 

Other: 288 

(14.9%) 

Male: 660 

(33.5%) 

N: 89878

Age 18-30yrs: 

16144 

(17.9%) 

Age 31-50yrs: 

31553 

(35.1%) 

Age: 51-64yrs: 

21084 

(23.4%) 

Age ≧ 65: 

21197 

(23.6%) 

White: 56553 

(65.2%) 

Black: 10906 

(12.6%) 

Other: 19306 

(22.3%) 

Male: 30194 

(33.6%)

Rosemurgy A 

201550

Retrospective 

analysis 

Y 

N

1 institution No N: 232 N: 31 

Elective: 

100% 

N: 201 

Ross S 201453

Retrospective 

analysis 

Y 

N

1 institution No N: 232 N: 31 N: 201 

Spinoglio G 

201237

Retrospective 

analysis 

N 

Y 

1 institution/ 1 

surgeon 

No N: 50 N: 25

Age: 54.2 (17.1) 

Male: 5 (20%) 

BMI: 23.7 (3.9) 

Sympt

cholelithiasis: 23 

(92%) 

Acute cholecyst: 0 

Other: 2 (8%) 

Elective: 100% 

N: 25

Age: 52.5 

(17.9) 

Male: 3 

BMI: 24.5 (4.7) 

Acute 

cholecyst: 0 

Elective: 100% 
Robot-assisted Procedures in General Surgery Evidence Synthesis Program

127

Strosberg DS 

201654

Retrospective 

analysis 

Y 

N 

1 institution No N: 156 N: 142

Sympt

cholelithiasis: 

92 (64.79%) 

Acute 

cholecyst: 1 

(0.7%) 

Other: 27 

(19.01%) 

N: 114 

Sympt

cholelithiasis: 

54 (47.3%) 

Acute 

cholecyst: 14 

(12.28%) 

Other: 9 

(7.89%) 

Strosberg DS 

201751

Retrospective 

analysis 

Y 

N 

1 institution/ 1 

surgeon 

No N: 237 N: 140

Age 47 (17-

94) 

Male: 44 

(32.4%) 

White: 120 

(85.7%) 

BMI: 30.3 

(17.1-68.8) 

Diabetes: 20 

(14.3%) 

Sympt

cholelithiasis: 

83 (59.3%) 

N: 97 

Age: 47 (17-

82) 

Male: 31 

(32%) 

Whit: 82 

(84.5%) 

BMI: 28.8 

(18.9-46.4) 

Diabetes: 16 

(16.5%) 

Sympt

cholelithiasis: 

52 (53.6%) 

Su WL 

201638

Retrospective 

analysis 

N 

Y 

1 institution No N: 114 N: 51

Age: 53.64 

(15.54) 

Male: 18 (35.29%)

BMI: 23.6 (3.8) 

Sympt

cholelithiasis: 33 

(64.7%) 

Acute cholecyst: 

10 (19.61%) 

Other: 8 (15.69) 

N: 63 

Age: 50.94 

(13.79) 

Male: 23 

(36.51%) 

BMI: 246 (3.11) 

Sympt

cholelithiasis: 

37 (58.73%) 

Acute 

cholecyst: 15 

(23.81%) 

Other: 15 

(23.81%) 

Teoh AY 

201731

Prospective 

comparative 

study 

Not reported 

N

2 hospitals No N: 24 N: 14 N: 10 

Wren SM 

201129

Prospective 

analysis of 

SSRC with 

retrospective 

comparison to 

lap chole

1 institution No N: 20 N: 10 

Age: 58.1 (15.9) 

BMI: 27.7 (3.3) 

Male: 7 (70%) 

Sympt

cholelithiasis: 

100% 

N: 10 

Male: 7 (70%) 

Age: 61.8 (15.6) 

BMI: 28.4 (6.2) 
Robot-assisted Procedures in General Surgery Evidence Synthesis Program

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Y

Y

cholecyc = cholecystitis; cholelith = cholelithiasis; sympt = symptomatic

Intra-operative Outcomes

Author 

Year 

Population 

Study Design

US (y/n) 

VA (y/n) 

Intraoperative Outcomes (<30d)

OR, time, min (SD) 

EBL, mL (SD) 

Transfusions, % 

Conversion 

 To Open, % 

 To Lap, % 

Major Complications, N (%) 

Single-Port Robot Single-Port Lap Multi-Port 

Robot 

Multi-Port Lap Unspecified Robot Unspecified Lap Specified combined 

single and multiport Robot

Specified combined 

single and 

multi-port Lap

Abel S

201932

Retrospective cohort 

Y 

N

Aggarwal R

202022

Retrospective cohort 

N 

N 

OR time: 86.5 

(60.5-106.5)* 

Docking time: 

11.5 (9-13)* 

Console time: 

30.8 (23.5-35)*

Intraoperative 

event (bleeding): 

1 (5.0%) 

Conversion to 

lap: 2 (10%) 

OR time: 31.5 (26-

41)* 

Intraoperative event: 

0 (0%) 

Albrecht R 

201717

Retrospective 

(matched-pair analysis) 

N 

N 

OR time: 104.2 

(44.8) 

Conversion: 2 

Complications: 8 

(bleeding: 2, 

gallbladder 

opening: 4, 

other: 2)

OR time: 91.9 (38.5)

Conversion: 1 

Complications: 3 

(bleeding: 1, 

gallbladder opening: 

2) 

Altieri MS 

201645

SPARCS database 

Prospective cohort 

Y 

N

Aragon RJ 201645

Prospective 

OR time: 81.3 

(23.3) 

OR time: 62.3 

(21.6) 

OR time: 80.9 

(24.8) 
Robot-assisted Procedures in General Surgery Evidence Synthesis Program

129

observational study 

Y 

N 

Case start time: 

10.1 (8.7) 

Setup time: 4.4 

(2.7) 

Robot time: 39.7 

(15) 

Cases "not 

completed via 

intended 

approach": 13 

(9.8%) 

Conversion to lap: 

7.6% 

Conversion to 

open: 0.7%

Cases "not 

completed via 

intended 

approach": 4 

(11.1%) 

Conversion to 

lap: 5.6% 

Case start time: 

17.2 (8.7) 

Setup time: 6.3 

(3.7) 

Robot time: 38.2 

(15.5) 

Cases "not 

completed via 

intended 

approach": 7 

(4.3%) 

Conversion to 

lap: 3.7% 

Conversion to 

open: 0.6% 

Autin RL 201539

Retrospective analysis 

Y N

Balachandran B

201723

Retrospective cohort 

Y 

N 

OR time: 89.4 

(27.8) 

Robotic time: 57 

(14.7) 

Docking time: 6.8 

(5.2) 

EBL: Minimal 

Conversion to 

Open: 13 (3.2%)

Conversion to Lap : 

12 (2.9%) 

Major 

complications: 0

OR time: 92.6 (31.9) 

EBL: Minimal 

Conversion to open: 

13 (4.9%) 

Major complications: 

0 

Buzad FA 

201333

Prospective cohort with 

historically 

(retrospective) 

matched-pairs 

Y 

N 

Docking time: 6.6 

(2.0) 

Console time: 50.7 

(17.9) 

Incision to close: 

84.6 (20.5) 

EBL 8.4 (7.3) 

Transfusions: 0 

Major 

complications: 0 

Incision to close: 

85.5 (11.8) 

EBL: 12.0 (7.5) 

Transfusions: 0 

Major 

complications: 0 

Calatayud D 

2012116

Retrospective analysis 

Y N

OR time: 90.81

Conversion to 

open: 0 

OR time: 89.45 

Conversion to open: 

2 

Chung PJ 

201524

Retrospective cohort 

Y N

Docking time: 11.5 

(5.7) 

Console time : 52.8 

(5.7) 

OR time: 111.5 

OR time: 106 (41)

Conversion to open: 

11 (15.7%) 
Robot-assisted Procedures in General Surgery Evidence Synthesis Program

130

(31.1) 

EBL: N/R 

Conversion to 

open: 1.4% (1)

Eid JJ

202021

Retrospective cohort 

Y 

N 

OR time: 93.4 

(15.4) 

EBL: 10.8 (9.9) 

CBD Injury: 0 

(0%)

Conversion to 

open: 0 (0%)

OR time: 101.3 

(49.1) 

EBL: 21.7 (32) 

CBD Injury: 1 

(1.4%) 

Conversion to open: 

3 (4.3%)

Farnsworth J 

201846

Observational 

(prospectively collected 

registry) 

Y 

N

OR time: 158 (38)

Conversion to open: 

0 

OR time: 135 (62)

Conversion to open: 

5 (1.5%) 

Farukhi MA 2017 52

Case control 

retrospective analysis 

Y 

N

Gonzalez AM 

201334

Retrospective cohort 

Y 

N

Surgical time (skin 

to close): 63 (25.2) 

Conversion to 

Open: 0% (0) 

Surgical time 

(skin to close): 

37.1 (13.3) 

Conversion to 

Open: 0% (0) 

Grochola LF 

201913

RCT 

No (Switzerland) 

No 

Console time: 35 

(21-107) 

OR time: 85.5 (48-

148) 

EBL: 5.0 (0-150) 

Conversion to 

Open: 0 

Conversion to 4 

port LC: 2 

Complications: 40% 

(12): 8 peritoneal 

tears + 4 minor 

bleeding

OR time: 74 (31-

135) 

EBL: 3.5 (0-300) 

Conversion to 

Open 

Conversion to 4 

port LC: 3 

Complications: 

46.7% (14): 11 

peritoneal tears 

+ 3 minor

bleeding

Gustafon M

201636

Observational 

(retrospective analysis 

of prospective 

database) 

Y 

N

OR time: 98 (37)

Conversion to 

multiport or open: 

8% 

Major 

complications: 0 

OR time: 68 (19)

Conversion to 

multiport or 

open: 11% 

Major 

complications: 0 
Robot-assisted Procedures in General Surgery Evidence Synthesis Program

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Hagen ME

201825

Retrospective cohort, 

matched pair 

N 

N 

OR time: 97 (39)

Conversion: 4% (4) 

 Complications: 4% 

(4)

Bleeding: 2% (2) 

Organ lesion: 2% 

(2)

OR time: 93.5 (32.5)

Conversion: 1% (1) 

Complications: 0 

Hagen ME 2017 30

Retrospective, casematched analysis 

Y 

N

OR time: 93.9 OR time: 82.5 

Hawasli A

201655

Observational 

(retrospective) 

Y 

N

Case time: 121 (15.4)

OR time: 86.6 (14.3) 

Case time: 98.4 

(27.5) 

OR time: 63.9 (25.9) 

Heemskerk J 

201414

Prospective 

Randomized Trial 

N 

N

OR (skin to 

close): 86 

Conversions: 0 

Major 

complications: 0 

OR (skin to close): 

48 

Conversions: 0 

Major complications: 

0 

Higgins RM 

201761

Surgical Profitability 

Compass Procedure 

Cost Manager System 

Database 

Retrospective analysis 

Y 

N

Mean case duration: 

84.3 (25.2) 

Mean case duration: 

75.5 (30.1) 

Jang EJ 

201940

Retrospective analysis 

N 

N 

OR time: 107.92 

(24.950) 

Conversion (to lap 

or open): 2 (5.1%) 

Bile spillage during 

operation: 6 

(15.4%) 

Use of additional 

robotic arm or port: 

0 

Complication: 0 

OR time: 60.99 

(17.810) 

Conversion (to 

lap or open): 2 

(2.6%) 

Bile spillage 

during operation: 

9 (11.5%) 

Use of additional 

robotic arm or 

port: 10 (12.8%) 

Complication: 5 

(6.4%)

Kaminski JP

201458

NIS dataset 

Retrospective analysis 

Y 

N

2010

Conversions: 0% 

 Intraoperative 

complications: 4.5% 

2010

Conversions: 0.32% 

 Intraoperative 

complications: 1.4% 

2011
Robot-assisted Procedures in General Surgery Evidence Synthesis Program

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2011 Conversions: 

1.66% 

Intraoperative 

complications: 4.0% 

Conversions: 0.29%

 Intraoperative 

complications: 1.3% 

Kane WJ 

202057

Retrospective Cohort 

Y 

N

OR time: 185 (175-

195)* 

OR time: 160 (135-

175)* 

Khorgami Z

201949

NIS 

Retrospective analysis 

Y 

N

Kudsi OY 

201715

Randomized controlled 

trial 

Mixed (7 institutions in 

US, 1 in Greece) 

N 

OR time: 61 (27.5) 

EBL: 13.06mL 

Transfusions: 0 

(0%)

Coversions to 

open: 0 (0%) 

Intraoperative 

complications: 0 

(0%) 

OR time: 44 (19.9)

EBL: 15.83mL 

Transfusions: 0 

(0%)

Conversions to 

open: 0 (0%) 

Intraoperative 

complications: 0 

(0%) 

Lee JH 201927

Retrospective analysis 

Y 

N 

OR time: 46.9 

(12.1) 

Docking time from 

incision to 

completion fo 

docking procedure: 

7.1 (5-20) 

Console time: 17.8 

(5-65) 

Conversion to 

open: 0 

Conversion to lap 

(4-port): 3 

Intraoperative bile 

spillage: 5.4% 

OR time: 53.4 

(16.6) 

Conversion to 

open: 0 

Conversion to 3-

port lap 

procedure: 3 

Addition of 1 

additional port: 5 

Intraoperative 

bile spillae: 7.4% 

Lescouflair T 201442

Retrospective review of 

prospectively 

maintained database 

Y 

N

OR time: 96. 

Conversion rate: 

9% 

OR ime: 65.2

Conversion rate: 

11% 

Lee EK 

201726

Retrospective analysis 

N 

N 

OR time (total): 

121.6 (22.2) 

Anesthesia time: 

115.7 (22.3) 

Surgery time: 86.8 

(21.7)

OR time (total): 71.9 

(10.4) 

Anesthesia time: 

65.9 (10.5) 

Surgery time: 34 

(9.6) 
Robot-assisted Procedures in General Surgery Evidence Synthesis Program

133

Lee SR

201841

Retrospective analysis 

N 

N 

Docking time: 10.75 

(4.33) 

Console time: 

44.84 (13.83) 

Total OR time: 

95.32 (20.27) 

Total OR time 

minus docking time: 

82.77 (18.27 

EBL: 38.20 (27.05) 

LOS: 2.26 (0.92) 

Intraoperative 

complications: 0 

(0%)

Total OR time: 

37.67 (19.73) 

EBL: 34.33 (32.59) 

LOS: 2.43 (1.73) 

Intraoperative 

complications: 0 

(0%)

Li YP

201728

Retrospective analysis 

N N

OR time: 75.7 

(31.3) 

Conversion to open 

or lap: 0 (0%) 

OR time: 64.37 

(30.61) 

Conversion to open: 

7 (1.9%) 

Main WPL

201718

Retrospective analysis 

Y N

OR time: 80 

(29.12) 

Conversion to 

open: 0 (0%) 

OR time: 60.22 

(29.78) 

Conversion to open: 

0 (0%) 

Mitko J 

201620

Retrospective analysis 

Y N

OR time: 80 OR time: 62 

Moore MD 201643

Retrospective analysis 

Y 

N 

OR time (skin to 

skin): 120 (32) 

EBL (median): 10 

(0-50) 

Conversion to 

open: 0 

Additionalports: 0 

Intraoperative 

complications: 0 

OR time (skin to 

skin): 79 (35) 

EBL (median): 

10 (5-150) 

Conversion to 

open: 0 

Additional ports: 

3 (10%) 

Intraoperative 

complications: 0 

Pietrabissa A

201616

Prospective, 

randomized, doubleblind trial 

N 

N 

OR time (total): 98 

(34) 

Docking time: 23 

(7) 

Dissection time: 56 

(26) 

Closure time: 19 (5) 

Bile spillage: 2 (6%) 

Minor bleeding: 3 

(10%) 

Liver damage at 

GB fossa: 1 (3%) 

Conversions: 0 

OR time (total): 87 

(30) 

Dockingtime: 15 (6) 

Dissection time: 44 

(16) 

Closure time: 11 (5) 

Bile spillage: 5 

(16%) 

Minor bleeding: 4 

(13%) 

Liver damage at GB 

fossa: 3 (10%) 

Conversions: 0 
Robot-assisted Procedures in General Surgery Evidence Synthesis Program

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Pokala B

201956

Retrospective analysis 

of Vizient database 

Y 

N

Rosemurgy A 

201550

Retrospective analysis 

Y 

N

OR time: 141 (25.38) OR time: 102 (32.7)

Ross S 201453

Retrospective analysis 

Y 

N

OR time: 141 (25.38) OR time: 102 (32.7) 

Spinoglio G 

201237

Retrospective analysis 

N 

Y

OR time: 62.7 

(16.6) 

Intraoperative 

complications: 0 

OR time: 83.2 

(21.1) 

Intraoperative 

complications: 0 

Strosberg DS 

201654

Retrospective analysis 

Y 

N

OR time: 80

Conversion to open: 

1 (0.7%) 

EBL: 20.15 

OR time: 68 

Conversion to open: 

7 (6.14%) 

EBL: 42.01 

Strosberg DS 

201751

Retrospective analysis 

Y 

N 

OR time: 74.5 (47-

293) 

EBL: 10 (2-200) 

Transfusions: 0 (0%) 

Conversions to open: 

1 (0.7%) 

OR time: 56 (35-

244) 

EBL: 10 (5-600) 

Transfusions: 1 

(1%)

Conversion to open: 

7 (7.2%) 

Su WL 

201638

Retrospective analysis 

N 

Y

OR time: 71.30 

(48.88) 

Conversion rate: 0 

OR time: 74.70 

(30.16) 

Conversion rate: 

2 (3.17%) 

Teoh AY 201731

Prospective 

comparative study 

Not reported 

N

OR time: 62.3 

(22.6) 

Conversion: 0 

OR time: 72.1 (19.2) 

Conversion: 0 

Wren SM 

201129

Prospective analysis of 

SSRC with 

retrospective 

comparison to lap chole 

Y 

Y

OR time: 105.3 (82-

139) 

Major 

complications: 0 

Conversion: 1 (1%) 

OR time: 106.1 (70-

142) 

Major complications: 

1 (10%) 

Conversion: 0 
Evidence Synthesis Program

135

Robot-assisted Procedures in General Surgery

Short-term Outcomes 

Author 

Year 

Population 

Study Design

US (y/n) 

VA (y/n) 

Short-Term Outcomes (<30d)

Readmissions, mean (SD) 

ED visits, mean (SD)

LOS, mean days (SD) 

Mortality, N (%) 

Complications, N (%) 

Common Bile Duct Injury, N (%) 

Bile Leak, N (%) 

Retained stone, N (%) 

Reoperation, N (%) 

Pain 

Narcotic use 

Return to work

Single-Port 

Robot 

Single-Port 

Lap

Multi-Port 

Robot 

Multi-Port Lap Unspecified 

Robot

Unspecified Lap Specified combined 

single and multi-port 

Robot

Specified combined 

single and multi-port 

Lap

Abel SA

201932

Retrospective 

cohort 

Y 

N

Postoperative 

complications: 43 

(15%) 

Postoperative 

complication: 41 

(14%) 

Aggarwal R

202022

Retrospective 

cohort 

N 

N

Postoperative 

events: 5 (25%) 

Bile Leak: 0 (0%) 

Wound infection 

:1 (5%) 

Bowel 

obstruction: 1 

(5%)

Constipation: 1 

(5%)

Gastroenteritis: 1 

(5%) 

Pain: 1 (5%)

Postoperative 

events: 5 (25%) 

Bile Leak: 1 (5%) 

Wound infection :3 

(15%) 

Bowel obstruction: 0 

(0%)

Constipation: 0 (0%) 

Gastroenteritis: 0 

(0%) 

Pain: 1 (5%) 

Albrecht R 

201717

Retrospective 

(matched-pair 

analysis) 

N 

N 

Postoperative 

LOS: 3.8 (4.7) 

Total LOS: 3.9 

(4.8) 

Postoperative 

pain: 11 (50%) 

Postoperative 

pain duration 

(None= 0, Less 

than 5d = 1, Less 

than 1 wk= 2, 

Between 7-14 

days= 3, More 

than 2 weeks = 

4): 1.55 (1.77)

Postoperative LOS: 

2.8 (1.3) 

Total LOS: 3.5 (2.3) 

Postoperative pain: 

8 (34.8%) 

Postoperative pain 

duration (None= 0, 

Less than 5d = 1, 

Less than 1 wk= 2, 

Between 7-14 days= 

3, More than 2 

weeks = 4): 0.74 

(1.18) 

Reoperation: 0 
Robot-assisted Procedures in General Surgery Evidence Synthesis Program

136

Reoperation: 1 

(4.5%) 

Altieri MS 

201645

SPARCS 

database 

Prospective 

cohort 

Y 

N

LOS: 4.92 (8.95)

Complications: 38 

(20.43%) 

LOS: 5.7 (8.71)

Complications: 

22,618 (20.59%) 

Aragon RJ 

201444

Prospective 

observational 

study 

Y 

N

Requirement for 

hospital stay: 

8.3% 

Hospital 

readmission: 

6.8% 

Reoperation: 1 

Requirement for 

hospital stay: 

0% 

Hospital 

readmission: 

11.1% 

Reoperation: 1 

Requirement for 

hospital stay: 

0.6% 

Hospital 

readmission: 

0.6% 

Autin RL 201539

Retrospective 

analysis 

Y 

N

Balachandran B

201723

Retrospective 

cohort 

Y 

N 

Readmission: 13 

(3.1%) 

ED Visits: 38 

(9.2%) 

LOS: 1.9 (3.1) 

Bile leakage: 1 

(0.2%) 

Wound infection: 

16 (3.9%) 

Abdominal pain: 

35 (8.4%)

Readmission: 4 

(1.5%) 

ED visits: 14 (5.3%) 

LOS: 2.4 (2.3) 

Bile leakage: 2 

(0.8%) 

Wound infection: 3 

(1.1%) 

Abdominal pain: 11 

(4.2%) 

Buzad FA 

201333

Prospective 

cohort with 

historically 

(retrospective) 

matched-pairs 

Y 

N

Readmission: 1

Pain: 1 

Readmission: 0

ED visit: 1 

Pain: 1 

Wound 

infection: 1 

Calatayud D 

2012116

Retrospective 

analysis 

Y 

N

LOS: 1.39 

CV Grade 1&2: 

19.3% 

LOS: 1.37

CV Grade 1&2: 

17.6% 

Bile leak: 1 

Chung PJ 

201524

Retrospective 

Readmissions: 

2.8% (2) 

LOS: 1.5 (3.8)

Readmissions: 

4.3% (3) 

LOS: 3.2 (3.6) 
Robot-assisted Procedures in General Surgery Evidence Synthesis Program

137

cohort

Y 

N 

Mortality: 0 

Common Bile 

Duct: 0 

Retained stone: 1 

Mortality: 0 

Common Bile 

Duct: 0 

Pain: 1 

(requiring 

readmission)

Eid JJ

202021

Retrospective 

cohort 

Y 

N 

30d 

Readmission: 0 

(0%) 

LOS: 0.8 (0.4) 

Bleeding: 0 (0%) 

UTI: 1 (5%) 

SSI: 1 (5%)

30d Readmission: 0 

(0%) 

LOS: 2.7 (2.1) 

Bleeding: 2 (2.8%) 

UTI: 0 (0%) 

SSI: 0 (0%) 

Farnsworth J 

201846

Observational 

(prospectively 

collected registry) 

Y 

N

LOS: 1.4 (1.4) LOS: 2.4 (2.6) 

Farukhi MA 

201752

Case control 

retrospective 

analysis 

Y 

N

Gonzalez AM 

201334

Retrospective 

cohort 

Y 

N 

LOS: 1.2 

(2.2)Complication 

rate: 1.8% (3) 

Superficial Site 

infection: 1 

Deep surgical site 

infection: 2

LOS: 1.3 (5.3) 

Complication 

rate: 1.8% (3) 

Retained stone: 

1 

Grochola LF 

201913

RCT 

No (Switzerland) 

No 

LOS: 1.9 (1-4) 

Complications: 

13.3% (4) 

Grade I: 6.7% (2) 

Grade II: 6.7% (2) 

Grade III: 0 

Grade IV: 0 

Grade V: 0 

Superficial wound 

infection: 3.3% 

(2)

LOS: 3.06 (1-

26) 

Complications: 

23.3% (7) 

Grade I: 13.3% 

(4)

Grade II: 3.3% 

(1) 

Grade III: 3.3% 

(1)

Grade IV: 3.3% 

(1) 

Grade V: 0 

Superficial 

wound infection: 

3.3% (1) 

Retained stone: 

3.3% (1) 
Robot-assisted Procedures in General Surgery Evidence Synthesis Program

138

Gustafon M

201636

Observational 

(retrospective 

analysis of 

prospective 

database) 

Y 

N 

Readmissions: 0

LOS (Number of 

patients staying 

>24hrs): 1

Complications: 0

Days taking

narcotics (mean):

2.3 (1.3)

Days until return

to normal funtion

(mean): 4.0 (2.0)

Readmissions: 

0 

LOS (Number of 

patients staying 

>24hrs): 0

Complications:

0

Days taking

narcotics

(mean): 1.7

(1.2)

Days until return

to normal

function (mean):

2.3 (1.1)

Hagen ME

201825

Restrospective 

cohort, matched 

pair 

N 

N 

LOS: 1.9 (1.7) 

Minor 

complication 

(Clavien I or II): 

2% (2)

Major 

compication 

(Clavien II or 

higher): 1% (1)

LO: 1.7 (1.6)

Minor complication 

(Clavien I or II): 2% 

(2)

Major complication 

(Clavien II or higher): 

1% (1) 

Hagen ME 201730

Retrospective, 

case-matched 

analysis 

Y 

N

LOS: 2.4 

Reoperation: 0 

LOS: 2.3 

Reoperation: 0 

Hawasli A

201655

Observational 

(retrospective) 

Y 

N

LOS: 1.0 (0) LOS: 1.02 (0.15)

Heemskerk J 

201414

Prospective 

Randomized Trial 

N 

N

Higgins RM 

201761

Surgical 

Profitability 

Compass 

Procedure Cost 

Manager System 

Database 

Retrospective 

analysis 

Mean LOS: 1.0 (0) Mean LOS: 1.1 (0.3) 
Robot-assisted Procedures in General Surgery Evidence Synthesis Program

139

Y

N

Jang EJ 

201940

Retrospective 

analysis 

N 

N 

LOS: 1.79 (1.031)

Pain score after 

immediate 

surgery: 4.95 

(1.905) 

Pain score at 

discharge: 1.92 

(0.900) 

LOS: 2.38 

(1.209) 

Pain score after 

immediate 

surgery: 5.00 

(1.405) 

Pain score at 

discharge: 2.35 

(1.209) 

Kaminski JP

201458

NIS dataset 

Retrospective 

analysis 

Y 

N

2010

LOS: 3.63 

2011 

LOS: 4.59 

2010

LOS: 4.14 

2011 

LOS: 4.1 

Kane WJ

202057

Retrospective 

Cohort 

Y 

N

30d readmission: 0 

(0%)

LOS: 0.1 (0.7) 

30d readmission: 27 

(2.6%) 

LOS: 0.8 (1.9) 

Khorgami Z

201949

NIS 

Retrospective 

analysis 

Y 

N

LOS: 2.9 (2) LOS: 2.8 (2.1) 

Kudsi OY 

201715

Randomized 

controlled trial 

Mixed (7 

institutions in US, 

1 in Greece) 

N

LOS: 16.67 hours

Postoperative 

complications: 4 

(5%)

Bile leak: 0 (0%) 

Wound infection: 

2 (%)

DVT/PE: 1 (1%) 

LOS: 13.93 hours

Postoperative 

complications: 2 

(4%)

Bile leak: 1 (2%) 

Wound infection: 1 

(2%) 

Lee EK 

201726

Retrospective 

analysis 

N 

N 

LOS: 4.3 (0.5)

No of analgesics 

given (preop): 0 

(0-0) 

No of analgesics 

given during 

surgery: 1 (0-3) 

No of analgesics 

given (recovery 

room): 0 (0-1) 

No. of analgesics 

given (postop): 1 

(0-9)

LOS: 4.7 (0.8) 

No of analgesics 

given (preop): 0 (0-

4) 

No of analgesics 

given during surgery: 

1 (0-3)

No of analgesics 

given (recovery 

room): 0 (0-0) 

No. of analgesics 

given (postop): 1 (0-

6)
Robot-assisted Procedures in General Surgery Evidence Synthesis Program

140

Pain level 

(preop): 4 (0-8)

6hrs postop: 2 (0-

5) 

First day postop: 

2 (0-4)

Second day 

postop: 0 (0-4) 

One week 

postop: 0 (0-2)

Pain level (preop): 0 

(0-8) 

6hrs postop: 2 (0-5) 

First day postop: 2 

(0-6) 

Second day postop: 

2 (0-5)

One week postop: 2 

(0-3) 

Lee SR

201927

Retrospective 

analysis 

N 

N 

Postoperative 

complications: 0 

(0%) 

Wound infection: 

0 

Bile leak: 0 

Pain rating score 

(1h): 4.75 (1.24) 

Pain rating score 

(6h): 2.54 (0.59) 

Pain rating score 

(1d): 2.25 (1.02)

Postoperative 

complications: 0 

(0%) 

Wound infection: 0 

Bile leak: 0 

Pain rating score 

(1h): 4.70 (1.22) 

Pain rating score 

(6h): 2.85 (1.24) 

Pain rating score 

(1d): 2.55 (1.12) 

Lee JH 201841

Retrospective 

analysis 

Y N

LOS: 3.3 (1.7) 

Bile duct injury: 0 

LOS: 4.0 (1.8) 

Bile duct injury: 

0 

Lescouflair T 

201442

Retrospective 

review of 

prospectively 

maintained 

database 

Y N

Narcotic use 

duration: 2.4 

Time to 

independent 

performance of 

daily activities: 4 

Narcotic use 

duration: 1.6 

Time to 

independent 

performance of 

daily activities: 4 

Li YP

201728

Retrospective 

analysis 

N 

N 

LOS: 3.73 (1.77)

Mortality: 0 (0%) 

Complications: 3 

(3.8%) 

CG grade I: 2 

(2.5%) 

CV Grade II: 0 

(0%)

CV Grade III-a: 0 

(0%)

CV Grade III-b: 1 

(1.28%) 

CV Grade IV: 0 

(0%)

Residual CBD 

Stone: 0 (0%) 

Bile leak: 0 (0%)

LOS: 4.35 (0.75)

Mortality: 0 (0%) 

Complications: 75 

(20.4%) 

CV Grade I: 50 

(13.6%) 

CV Grade II: 14 

(3.81%) 

CV Grade III-a: 9 

(2.45%0) 

CV Grade III-b: 2 

(0.55%) 

CV Grade IV: 0 (0%) 

Residual CBD 

Stone: 2 

Bile leak: 2 

Biliary stricture: 2 
Robot-assisted Procedures in General Surgery Evidence Synthesis Program

141

Biliary stricture: 0 

(0%) 

Subhepatic fluid 

collection: 0 (0%) 

Wound infection: 

0 (0%) 

Analgesic 

requirement 

(days): 0.64 

(2.11)

Subhepatic fluid 

collection: 3 

Analgesic 

requirement (days): 

1.13 (3.30) 

Wound infection: 10 

(2.7%) 

Main WPL

201718

Retrospective 

analysis 

Y 

N 

ED visits: 13 

(7.2%) 

Bile lek: 2 (1.1%) 

Retained CBD 

Stone: 3 (1.67%) 

Mortality: 0 (0%) 

SSI: 2 (1.1%) 

Present to ER w/ 

abd pain: 1 

(0.55%)

ED visits: 69 (7.2%)

Bile leak: 8 (0.83%) 

Retained CBD 

Stone: 2 (0.2%) 

Mortality: 3 (0.3%) 

SSI: 4 (0.41%) 

Present to ER w/ 

abd pain: 31 (3.2%) 

Mitko J 

201620

Retrospective 

analysis 

Y 

N

LOS: 0.23 

Readmission (for 

abdominal pain): 

0.55% 

Retained stone: 

1.7% 

LOS: 0.58 

Readmission (for 

abdominal pain): 

3.2% 

Retained stones: 

0.21% 

Moore MD 201643

Retrospective 

analysis 

Y 

N 

LOS (hours): 9.9 

(6.7) 

Postoperative 

complications: 1 

(4.8%) 

Choledocholithias

is: 1 

LOS (hours): 

13.1 (13.9) 

Postoperative 

complications: 2 

(6.9%) 

Choledocholithi

asis: 1 

Wound 

infection: 1 

Pietrabissa A

201616

Prospective, 

randomized, 

double-blind trial 

N 

N 

LOS: 1.2 (1-3)

Wound infection: 

2 

Patients with pain 

score greater 

than or equal to 

16: 3 (10%) 

Median pain sum: 

3 (1-8)

LOS: 1.2 (1-3)

Wound infection: 0 

Patients with pain 

score greater than or 

equal to 16: 2 (7%) 

Median pain sum: 4 

(1-9) 

Pokala B

201956

Retrospective 

analysis of Vizient 

database 

Y 

N 

Overall 

complications: 34 

(1.7%) 

Post-op infection: 7 

(0.4%) 

Post-op sepsis: 3 

(0.2%) 

7d readmission: 16 

Overall 

complications: 851 

(0.9%) 

Post-op infection: 

133 (0.2%)

Post-op sepsis: 53 

(0.1%) 

7d readmission: 998 
Robot-assisted Procedures in General Surgery Evidence Synthesis Program

142

(0.8%)

14d readmission: 

26 (1.3%) 

30d readmission: 

37 (1.9%) 

Mortality: 1 (0.1%) 

LOS: 3.27 (2.72) 

Percentage of 

patients prescribed 

opiates: 97.2% 

(1.0%)

14d readmission: 

1415 (1.6%) 

30d readmission: 

1749 (2.0%) 

Mortality: 40 

(<0.001%) 

LOS: 3.10 (2.22) 

Percentage of 

patients presribed 

opiates: 98.3%

Rosemurgy A 

201550

Retrospective 

analysis 

Y N

Ross S 201453

Retrospective 

analysis 

Y N

Spinoglio G 

201137

Retrospective 

analysis 

N Y

LOS: 1.1 (0.3)

Readmissions: 0 

Major 

complications: 0 

Wound infection: 

0 

LOS: 1.2 (0.7)

Readmissions: 

0 

Major 

complications: 0 

Strosberg DS 

201751

Retrospective 

analysis 

Y 

N 

Readmissions: 5 

(3.6%) 

LOS: 0 (0-4)

Bile duct injury: 0 

(0%)

Bile leak: 3 (2.1%) 

Wound infection: 1 

(0.7%) 

Reoperation: 2 

(1.4%) 

Readmissions: 4 

(4.1%) 

LOS: 0 (0-8)

Bile duct injury: 0 

(0%)

Bile leak: 1 (1%) 

Wound infection: 1 

(1%)

Reoperation: 1 (1%) 

Strosberg DS 

201654

Retrospective 

analysis 

Y 

N 

LOS: 0.55

60d readmission: 6 

(4.23%) 

Bile duct injury: 0 

Bile leak: 3 

(2.11%) 

Reoperation: 2 

(1.41%) 

LOS: 1.35 

60d readmission: 13 

(11.4%) 

Bile duct injury: 0 

Bile leak: 1 (0.88%) 

Reoperation: 2 

(1.75%) 

Su WL 

201638

Retrospective 

analysis 

N Y

LOS: 4.21 (0.72)

Bile leakage: 0 

(0%)

Pain scale: 2.11 

(0.76) 

LOS: 4.13 

(0.93) 

Bile leakage: 2 

(3.17%) 

Pain scale: 3.98 

(0.84)
Robot-assisted Procedures in General Surgery Evidence Synthesis Program

143

Wren SM 

201129

Prospective 

analysis of SSRC 

with retrospective 

comparison to lap 

chole 

Y 

Y

Pain (at 

discharge): 2.5 

(1.4) 

Pain (2-3 wks 

later): 0.67 (0.87) 

Teoh AY 201731

Prospective 

comparative 

study 

Not reported 

N

LOS: 1.4 (0.7)

Morbidity rate: 

14.3% 

LOS: 1 (0) 

Morbidity rate: 0% 

Long-term Outcomes

Author 

Year 

Population 

Study Design

US (y/n) 

VA (y/n) 

Long-Term Outcomes (>30d)

Readmissions 

Hernias 

GI-related complications 

Pain 

Quality of life 

% of patients that followed up at 6mo 

Single-port Robot Single-port Lap Multi-port Robot Multi-port Lap Unspecified 

Robot

Unspecified Lap Specified combined 

single and multiport Robot

Specified 

combined single 

multi-port Lap

Abel SA

201932

Retrospective cohort 

Y 

N

Port-site hernia: 23 (8%) Port-site hernia: 28 

(10%) 

Aggarwal R

202022

Retrospective cohort 

N 

N

Albrecht R 

201717

Retrospective 

(matched-pair analysis) 

N 

N

Altieri MS 

201645

SPARCS database 

Prospective cohort
Robot-assisted Procedures in General Surgery Evidence Synthesis Program

144

YN

Aragon RJ 201444

Prospective 

observational study 

Y N

Autin RL 201539

Retrospective analysis 

Y N

Port site hernias: 3 

(11.1%) 

Port site hernias: 6 

(22.2%) 

Balachandran B

201723

Retrospective cohort 

Y N

Umbilical incisional 

hernia: 27 (6.5%) 

Umbilical 

incisional hernia: 

5 (1.9%) 

Buzad FA 

201333

Prospective cohort with 

historically 

(retrospective) 

matched-pairs 

Y N

Calatayud D 

2012116

Retrospective analysis 

Y N

Chung PJ 

201524

Retrospective cohort 

Y N

Eid JJ

202021

Retrospective cohort 

Y N

Farnsworth J 

201846

Observational 

(prospectively collected 

registry) 

Y N

Farukhi MA 201752

Case control 

retrospective analysis 

Y N
Robot-assisted Procedures in General Surgery Evidence Synthesis Program

145

Gonzalez AM 

201334

Retrospective cohort 

Y N

Grochola LF 

201813

RCT 

No (Switzerland) 

No 

Incisional hernia: 6.7% 

(2) 

HRQoL (Preop, median): 

107(62-135) 

HRQoL (1mo postop, 

median): 123 (83-140) 

HRQoL (12mo postop, 

median): 123 (105-141) 

Body image (1mo postop, 

median): 37 (24-40) 

Body image (12mo 

postop, median): 35.5 

(20-40) 

Incisional hernia: 

6.7% (2) 

HRQoL (Preop, 

median): 109.5 

(39-131) 

HRQoL (1mo 

postop, median): 

120 (55-142) 

HRQoL (12mo 

postop, median): 

128 (94-143) 

Body image (1mo 

postop, median): 

38 (19-40) 

Body image (12mo 

postop, median): 

39 (22-40)

Gustafon M

201636

Observational 

(retrospective analysis 

of prospective 

database) 

Y N

Incisional hernia: 1 

(2.6%) 

Incisional hernia: 2 

(4.5%) 

Hagen ME

201825

Restrospective cohort, 

matched pair 

N N

Operation for incisional 

hernia: 7 (7.1%) 

Operation for 

incisional hernia: 

0 

Hagen ME 201730

Retrospective, casematched analysis 

Y N

Incisional hernia: 6 Incisional 

hernia: 0 

Hawasli A

201655

Observational 

(retrospective) 

Y N

Heemskerk J 

201414

Prospective 

Randomized Trial
Robot-assisted Procedures in General Surgery Evidence Synthesis Program

146

N

N

Higgins RM 

201761

Surgical Profitability 

Compass Procedure 

Cost Manager System 

Database 

Retrospective analysis 

Y 

N

Jang EJ 

201940

Retrospective analysis 

N 

N

Kaminski JP

201458

NIS dataset 

Retrospective analysis 

Y 

N

Kane WJ

202057

Retrospective Cohort 

Y 

N

90d readmission: 0 

(0%)

90d readmission: 

43 (4.1%) 

Khorgami Z

201949

NIS 

Retrospective analysis 

Y 

N

Kudsi OY 

201715

Randomized controlled 

trial 

Mixed (7 institutions in 

US, 1 in Greece) 

N

Lee EK 

201726

Retrospective analysis 

N 

N

Lee SR

201927

Retrospective analysis 

N 

N
Robot-assisted Procedures in General Surgery Evidence Synthesis Program

147

Lee JH 201841

Retrospective analysis 

Y 

N

Incisional hernia: 1 Incisional hernia: 1 

Lescouflair T 201442

Retrospective review of 

prospectively 

maintained database 

Y 

N

Li YP

201728

Retrospective analysis 

N 

N

Incisional hernia: 1 Incisional 

hernia: 2 

Main WPL

201718

Retrospective analysis 

Y 

N

Mitko J 

201620

Retrospective analysis 

Y 

N

Moore MD 201643

Retrospective analysis 

Y 

N

Pietrabissa A

201616

Prospective, 

randomized, doubleblind trial 

N 

N

Incisional hernia: 1 Incisional hernia: 0 

Pokala B

201956

Retrospective analysis 

of Vizient database 

Y 

N

Rosemurgy A 

201550

Retrospective analysis 

Y 

N

Ross S 201453

Retrospective analysis 

Y 

N
Robot-assisted Procedures in General Surgery Evidence Synthesis Program

148

Spinoglio G 

201137

Retrospective analysis 

N 

Y

Strosberg DS 

201751

Retrospective analysis 

Y 

N

Port site hernia: 0 Port site hernia: 0 

Strosberg DS 

201654

Retrospective analysis 

Y 

N

Su WL 

201638

Retrospective analysis 

N 

Y

Teoh AY 201731

Prospective 

comparative study 

Not reported 

N

Quality of life assessment 

score: 22.9 (2.7) 

Quality of life 

assessment 

score: 24.4 (3.1) 

Wren SM 

201129

Prospective analysis of 

SSRC with 

retrospective 

comparison to lap 

cholecystectomy 

Y 

Y
Evidence Synthesis Program

149

Robot-assisted Procedures in General Surgery

INGUINAL HERNIA REPAIR 

Author 

Year 

Population 

Study Design

US 

VA 

# Institutions/ 

Surgeons

Propensity 

Matching (y/n)

Total N

Patient Characteristics Preop

Total patients (N) 

Age, mean yr (SD) 

Race/Ethnicity

 NH-White, % 

 NH-Black, % 

 NH-Asian, % 

 NH-Other/Unknown, % 

 Hispanic, % 

Male, % 

BMI, mean (SD) 

ASA ≥ 3, %

Diabetes, % 

Smokers, % 

Hernia characteristics 

 Elective surgery, % 

 Primary hernia, % 

 Unilateral, % 

Pain, % 

Intraoperative Outcomes

OR time, min (SD) 

EBL, mL (SD) 

Transfusions, % 

Complications, %

Conversion 

 To Open, % 

 To Lap, % 

Mesh repair, % 

Surgical approach 

TEP, %

TAPP, %

Concurrent procedures, type, % 

Italicized text indicates that an 

outcome has been separately reported 

by laterality

Short-Term Outcomes (≤30d)

LOS, mean (SD) 

Readmissions, %

Reoperations, %

ED visits, mean (SD) 

Complications, %

SSO, %

 Seroma/Hematoma, % 

 Enterotomy, % 

 Pain, % 

 Narcotic use, % 

 Return to work, % 

 Retention, % 

 Other, % 

Mortality, % 

Italicized text indicates that an outcome 

has been separately reported by 

laterality

Long-Term Outcomes 

(>30d)

Follow-up at 1 year, % 

Length of follow-up, mean 

(SD)

Readmissions, %

Mesh infection, % 

Pain, %

Recurrence, %

QOL

Primary 

Multi-Variate 

Findings

Comments

Robot Lap Open Robot Lap Open Robot Lap Open Robot Lap Open

Abdelmoaty, 

201875

Robot vs lap 

Retrospective 

US 

32/164 (115 lap; 

49 robot) 

n 

N=2405

N=734

Elective 

 100% 

Primary

 86.2% 

Unilater

al 

 100% 

N=1671

Elective 

 100% 

Primary

 88% 

Unilateral 

 100% 

OR

Skin-skin

 87 

Room time 

 125 

Conversion 

 5.4% 

(open) 

Concurrent 

 0% 

OR

Skin-skin

 56 

Room time 

 90 

Conversion 

 5.3% 

(open) 

Concurrent 

 0%

LOS (d)

 0.26 

LOS (d)

 0.25 

Robotic 

significantly 

longer OR 

time 

(p<0.001 for 

both in-room 

and cut-to 

close) 

AlMarzooqi, 

201971

Robot vs lap vs

open 

Prospective 

(AHSQC) 

US 

n 

N=4613 

N=847

Age 

 59.0 

Male 

 91.0% 

BMI

 27.0 

Elective 

 100% 

Primary

 100% 

Unilater

al 

100%

N=1841

Age 

 60.0 

Male 

 93.0% 

BMI

 26.0 

Elective 

 100% 

Primary

 100% 

Unilateral 

 100% 

N=1925

Age 

 64.4 

Male 

 90.9% 

BMI

 25.9 

Elective 

 100% 

Primary

 100% 

Unilateral 

 100% 

Mesh

 100% 

TEP

 1% 

TAPP

 99% 

Mesh

 100% 

TEP

 67% 

TAPP

 33% 

Mesh

 92% 

SSO

 1.4% 

Seroma/ 

hematoma 

 2.7% 

SSO

 3.4% 

Seroma/ 

hematoma 

 5.8% 

SSO

 4.1% 

Seroma/ 

hematoma 

 13.9% 

1-yr F/U

6.0%

F/U

1y

Recur

2.0%

QOL*

12.9

1-yr

F/U

9.4%

F/U

1y

Recur

4.0%

QOL*

10.3

1-yr F/U

7.2%

F/U

1y

Recur

8.7%

QOL*

12.1

*

Calculated

based on a

median; 30-

day EuraHS

QOL score

Data pooled 

from 

subgroup 

analyses (by 

procedure 

type) 

Bittner, 201812

Robot vs lap vs

open

N=83

Age 

N=83

Age 

Pain 

(scale) 

4.0 (0.3)

Pain (scale)

 4.4 (0.3) 

Narc*

1-yr F/U

n=83

F/U (mo)

1-yr

F/U

N=83

*

Days to no

Rx
Robot-assisted Procedures in General Surgery Evidence Synthesis Program

150

Random sample 

from web-based 

research panel 

US 

na/na 

y 

N=166 

(526 unmatched) 

54.4 

(11.0) 

Male 

 97.6%

Pain 

(Rx)

 30.1% 

Pain 

(scale) 

 5.4 

(0.4) 

57.5 

(12.3) 

Male 

 100%

Pain (Rx) 

 25.3% 

Pain 

(scale) 

 5.8 (0.3) 

Narc*

 9.4 (1.5) 

RTW (d)

 17.8 (2.1) 

11.6 (1.7)

RTW (d)

 17.9 (2.8) 

5.7 (0.3)

Pain 

(scale) 

 1.5 (0.3)

F/U 

(mo)

 6.0 

(0.3)

Pain 

(scale) 

 1.1 

(0.2)

Bittner, 201812

Robot vs lap vs

open

Random sample 

from web-based 

research panel 

US 

na/na 

y 

N= 170 

(526 unmatched)

N=85

Age 

 53.2 

(11.9) 

Male 

 97.6% 

Pain 

(Rx)

 31.8% 

Pain 

(scale) 

 5.6 

(0.3) 

N=85

Age 

 56.2 

(12.0) 

Male 

 98.8% 

Pain (Rx) 

 29.4% 

Pain 

(scale) 

 5.8 (0.4) 

Pain 

(scale) 

 4.1 (0.3) 

Narc*

 9.4 (1.4) 

RTW (d)

 17.0 (2.0) 

Pain (scale)

 5.6 (0.3) 

Narc*

 10.6 (1.2) 

RTW (d)

 21.7 (2.4) 

1-yr F/U

n=85

F/U (mo)

5.7 (0.3)

Pain

(scale)

1.6 (0.3)

1-yr F/U

n=85

F/U

(mo)

6.7

(0.3)

Pain

(scale)

2.2

(0.3)

Postop pain 

(1 wk) 

significantly 

higher on 

open vs robot 

(p<0.01) 

*

Days to no

Rx

Pain rating = 

APGP score

Charles, 201868

Robot vs lap vs

open 

Prospective 

(NSQIP) 

US 

VA

1/10 (2 robotic, 8 

lap, 4 open) 

n 

N=510

N=69

Age*

 52 [39-

62] 

White 

 87% 

Male 

 85.5% 

BMI*

 24.9 

[22.9-

28.7] 

ASA

 14.5% 

Diabete

s 

 1.5% 

Smoker

s 

 23.2% 

Primary

 100% 

Unilater

al 

100%

N=241

Age*

 57 [45-67] 

White 

 88.4% 

Male 

 88.8% 

BMI*

 25.8 

[23.1-28.4] 

ASA

 15.4% 

Diabetes 

 0.4% 

Smokers 

 18.3% 

Primary

 100% 

Unilateral 

 100% 

N=191

Age*

 56 [48-

67] 

White 

 85.9% 

Male 

 91.6% 

BMI*

 25.1 

[23.2-

27.8] 

ASA

 28.8% 

Diabetes 

 1.6% 

Smokers 

 28.3% 

Primary

 100% 

Unilateral 

 100% 

OR

Room time*

 105 [76-

146] 

Txf

 0% 

Mesh 

 100% 

TAPP

 100% 

Concurrent 

 1.5% 

OR

Room time*

 81 [61-13] 

Txf

 0.4% 

Mesh 

 100% 

TAPP

 100% 

Concurrent 

 0.8% 

OR

Room 

time*

 71 [56-

88] 

Txf

 0% 

Concurre

nt 

 1.6% 

Readmit

 0% 

Comp 

 2.9% 

SSO

 2.9% 

Other 

 0% 

Mortality 

 0% 

Readmit

 2.1% 

Comp 

 3.3% 

SSO

 0% 

Other 

 1.7% 

Mortality 

 0% 

Readmit

 3.7% 

Comp 

 5.2% 

SSO

 0.5% 

Other 

 2.6% 

Mortality 

 0% 

Recur**

 0% 

Recur**

 0% 

Recur**

 0% 

Total 

operating 

time greater 

for robot 

(p<0.001) 

*

Median

[IQR]

**30-day

Gamagami, 

201869

N=444 

(652 

N=444 

(602 

OR

Skin-skin

OR

Skin-skin

LOS (d)

3.0 (2.6)

LOS (d)

5.7 (6.8)

30-day

postoperative

*

Postop

transfusion
Robot-assisted Procedures in General Surgery Evidence Synthesis Program

151

Robot vs open 

Retrospective 

US 

6/7 

y 

N=888 

(1,254 

unmatched) 

unmatch

ed) 

Age 

 55.8 

(15.9)

Male 

 89.4% 

BMI

 26.8 

(4.7) 

ASA3 

 25.2% 

Primary

 87.4% 

Unilater

al 

 84.5% 

unmatch

ed) 

Age 

 56.4 

(16.0)

Male 

 90.3% 

BMI

 27.0 

(5.0) 

ASA3 

 27.3% 

Primary

 87.4% 

Unilateral 

 84.0% 

74.0 (30.1)

Txf*

 0.5% 

Comp 

 0.5% 

Conversion 

 1.4% 

(open) 

Mesh 

 100% 

TAPP

 100% 

Concurrent 

 14.6% 

46.6 

(23.0) 

Txf*

 0.2% 

Comp 

 0% 

Mesh 

 100% 

Concurre

nt 

 13.7% 

Readmit

 2.5% 

Reop 

 0.5% 

Comp**

 7.2% 

SSO

 0.2% 

Seroma/ 

hematoma 

 1.1% 

Retention 

 2.3% 

Pain 

 0.7% 

Other 

 3.4% 

Mortality 

0%

Readmit

 2.3% 

Reop 

 1.6% 

Comp**

 9.5% 

SSO

 1.6% 

Seroma/ 

hematoma 

 2.3% 

Retention 

 0.5% 

Pain 

 2.5% 

Other 

 3.2% 

Mortality 

0.2%

complications 

higher in 

open 

(p=0.047) 

Shorter OR 

time (skin to 

skin) in open 

(p<0.0001) 

Lower 

inpatient LOS 

in robot 

(p=0.043) 

**Post-op 

complications 

stratified 

between 

“prior to d/c” 

and “postd/c, prior to 

30 days”. 

Pooled in this 

table. 

Holcomb, 201984

Robot vs open 

Prospective 

(AHSQC) 

US 

na/na 

n 

N=1170

N=540

Age 

 60 [48-

70] 

DM 

 8% 

Elective 

 100% 

Primary

 100% 

N=630

Age 

 65 [55-

73] 

DM 

 11% 

Elective 

 100% 

Primary

 100% 

TAPP

 100% 

Readmit

 1% 

Comp 

 5% 

SSO

 0.4% 

Seroma/ 

hematoma 

 1.6% 

Readmit

 1% 

Comp 

 5% 

SSO

 1.6% 

Seroma/ 

hematoma 

 1.4% 

Recur*

 0.2% 

Recur*

 0.0% 

*

30-day

recurrence

Huerta, 201970

Robot vs lap vs

open 

Retrospective 

US 

VA

1/3 (1 surgeon 

per approach) 

n 

N=1299 

N=71

Age 

 59.9 

(12.5) 

White 

 69.0% 

Black 

 22.5% 

Hispanic 

 7.0% 

Male 

 100% 

BMI

 27.5 

(5.2) 

ASA

 2.4 

(0.5) 

DM 

 15.5% 

Smoking 

33.8%

N=128

Age 

 58.3 

(12.4) 

White 

 73.4% 

Black 

 19.5% 

Hispanic 

 3.1% 

Male 

 100% 

BMI

 26.3 (4.1) 

ASA

 2.6 (0.6) 

DM 

 10.9% 

Smoking 

 40.6% 

Primary

49.9%

N=1100

Age 

 61.3 

(12.8) 

White 

 73.7% 

Black 

 20.5% 

Hispanic 

 5.2% 

Male 

 99.9% 

BMI

 26.6 

(4.3) 

ASA

 2.6 (0.6) 

DM 

 12.7% 

Smoking 

 32.6% 

Primary

OR

117.5 (61.8) 

Mesh 

 100% 

TAPP

 100% 

Concurrent 

 11.3% 

OR

 78.4 (27.1) 

Mesh 

 100% 

TEP

 100% 

Concurrent 

 11.7% 

OR

 65.5 

(26.1) 

Mesh 

 100% 

Concurre

nt 

 0.4% 

LOS

 0.3 (0.8) 

Comp 

 18.2% 

SSO

 0% 

Seroma/ 

hematoma 

 2.8% 

Retention 

 5.6% 

Pain 

 2.8% 

Ileus 

 0% 

Other 

 7.0% 

LOS

 0.11 (0.5) 

Comp 

 21.2% 

SSO

 0.8% 

Seroma/ 

hematoma 

 1.6% 

Retention 

 5.5% 

Pain 

 7.0% 

Ileus 

 0% 

Other 

 6.3% 

LOS

 0.24 (1.1) 

Comp 

 7.9% 

SSO

 0.8% 

Seroma/ 

hematoma 

 2.6% 

Retention 

 1.8% 

Pain 

 0.8% 

Ileus 

 0.7% 

Other 

 1.2% 

F/U (y)

 2.4 (0.8) 

Pain 

 14.1%

Recur 

 5.6% 

F/U (y)

 3.9 

(1.8) 

Pain*

 9.4%

Recur 

 3.9% 

F/U (y)

 5.6 

(3.6) 

Pain*

 1.5%

Recur 

 1.7% 

OR time for 

robot sig 

longer than 

both open 

and lap 

(p<0.001 for 

both) 

Robot 

significantly 

more 

inguinodynia 

than open 

(p<0.001) 

Robot 

significantly 

more urinary 

retention 

than open 

(p=0.03) 

*

Inguinodynia
Robot-assisted Procedures in General Surgery Evidence Synthesis Program

152

Primary

 74.6% 

Unilater

al 

 40.8% 

Unilateral

 19.0% 

99.2%

Unilateral 

 92.7% 

Robot had 

significantly 

more overall 

complications 

than open 

(p<0.001) 

Recurrence 

higher in 

robot vs open 

(p<0.02) 

Open had a 

longer f/u 

time than 

both lap and 

robot 

(p<0.001)

Janjua, 202077

Robot vs lap vs

open 

Prospective 

database (AHAHCUP) 

US 

na/na 

y 

N=35916 

Pooled

N=1480

Age 

>70:

19%

Race:

79%

white

8% AA

7%

Hispanic

1%

Asian

5%

other

Male:

95%

CCS ≥1:

91%

Elective:

75%

Unilater

al: 75%

N=7011

Age >70: 

42% 

Race: 

 76% white 

8% AA

 10% 

Hispanic 

 2% Asian 

 4% other 

Male: 81% 

CCS ≥1: 

42% 

Elective: 

35% 

Unilateral: 

68% 

N=27425

Age >70: 

46% 

Race: 

 70% 

white 

 12% AA 

 12% 

Hispanic 

2% 

Asian 

 4% other 

Male: 

85% 

CCS ≥1: 

49% 

Elective: 

22% 

Unilateral

: 92% 

LOS: 2.22 

(2.85) 

U/L: 2.2 

(2.8)

 B/L: 2.3 

(3.1)

LOS: 3.27 

(4.74) 

U/L: 3.5 

(5.2)

 B/L: 2.8 

(3.6)

LOS: 4.22 

(6.22) 

U/L: 4.3 

(6.3)

 B/L: 4 (5.3)

LOS for robot 

significantly 

decreased vs 

lap vs open 

(p<0.0001)

Janjua, 202077

Matched

N=1480 N=2960 N=2960 LOS: 2.22 

(2.85) 

LOS: 3.6 

(5.5) 

LOS: 5.0 

(8.2) 

LOS for robot 

significantly 

decreased vs 

lap vs open 

(p<0.0001)

Kakaishvili, 

201872

Robot vs lap vs

open 

Retrospective 

Israel 

1/na

N=24

Unilater

al 

 29.2% 

N=16

Unilateral 

 50% 

N=97

Unilateral 

 87.6% 

OR

 92.5 

OR

 79.0 

OR

 44.0 

LOS

 1.0 

Pain

*

 0 

Narc**

 1.0 

LOS

 1.0 

Pain

*

 2.0 

Narc**

 1.5 

LOS

 1.0 

Pain

*

 5.0 

Narc**

 3.0 

*

Median VAS

score

**Analgesia

(per day)

Postoperativ

e VAS level 

significantly 
Robot-assisted Procedures in General Surgery Evidence Synthesis Program

153

n 

N=137 

higher in 

open 

(p<0.001) 

Robot had a 

longer OR 

time than lap 

or open 

(p<0.001)

Khoraki 201978

Robot vs lap 

Retrospective 

cohort 

US 

1/4 

n 

N=183 

N=45

Age: 

49.6 

(13.7) 

Male: 

93.3% 

BMI: 

27.5 

(5.8) 

ASA ≥ 

3: 20% 

DM: 

4.4% 

Primary: 

88.9% 

Unilater

al: 

82.2% 

N=138

Age: 50 

(13.3) 

Male: 

96.4% 

BMI: 26.2 

(3.6) 

ASA ≥ 3: 

8.7% 

DM: 

10.1% 

Primary: 

95.7% 

Unilateral: 

70.3% 

OR time: 

116 (36) 

 U/L: 110 

(35)

 B/L: 143 

(33) 

Conversion 

to open: 0% 

Mesh: 

100% 

TAPP: 

100% 

TEP: 0% 

OR time: 95 

(44) 

 U/L: 88 

(37)

 B/L: 114 

(54) 

Conversion 

to open: 

0.7% 

Mesh: 

100% 

TAPP: 0%

TEP: 100% 

LOS: 0.13 

[0-2] 

Readmit: 3 

(6.7%)

Reop: 3 

(6.7%) 

Comp: 13 

(28.9%) 

SSI: 1 

(2.2%) 

Seroma: 5 

(11.1%) 

Hematoma: 

1 (2.2%) 

Retention: 

2 (4.4%) 

SBO: 2 

(4.4%) 

Ileus: 1 

(2.2%) 

LOS: 0.04 

[0-1] 

Readmit: 1 

(0.7%)

Reop: 0 

(0%)

Comp: 25 

(18.1%) 

SSI: 0 (0%) 

Seroma: 16 

(11.6%) 

Hematoma: 

1 (0.7%) 

Retention: 

7 (5.1%) 

SBO: 0 

(0%)

Ileus: 0 

(0%)

F/U: 30 d F/U: 30 

d 

Overall OR 

time longer 

for robot 

(p<0.01) and 

unilateral 

repairs 

(p<0.01); 

bilateral 

repairs not 

significant 

(p=0.06) 

No difference 

in conversion 

to open 

(p=0.57) 

Similar LOS 

(p=0.16), 

complications 

(p=0.14); 

increased 

reoperations 

with robot 

(p=0.01) and 

30-day

readmission

with robot

(p=0.04)

Knott, 201780

Robot vs lap vs

open 

Prospective 

(Truven 

MarketScan) 

na/na 

n 

N=75,981

N=262 

Primary

 100% 

N=25,433 

Primary

 100% 

N=50,28

6 

Primary

 100%

F/U

 1 y 

Recur 

 2.7% 

F/U

 1 y 

Recur 

 3.5% 

F/U

 1 y 

Recur 

 3.9% 

Rate of 

repeat IHR 

was 

significantly 

lower in lap 

vs open [HR 

0.90 (CI 

0.83-0.98), 

p=0.019] and 

trended lower 

in RAS vs 

open [HR 

0.69 (CI 

0.33-1.44), 

p=0.32]
Robot-assisted Procedures in General Surgery Evidence Synthesis Program

154

Kolachalam, 

201766

Robot vs open 

Retrospective 

US 

6/7 

y 

N=188

N=95

Age 

 53.5 

(11.9) 

Male 

 91.6% 

BMI

 33.6 

(3.8) 

ASA

 35.8% 

Unilater

al 

 87.4% 

N=93

Age 

 54.0 

(14.5) 

Male 

 88.2% 

BMI

 34.2 

(5.2) 

ASA

 33.3% 

Unilateral 

 86.0% 

OR

Skin-skin

 82.9 (35.7) 

Txf

 0% 

Conversion 

 3.2% 

(open) 

Comp 

 1.1% 

Mesh 

 100% 

TAPP

 100% 

Concurrent 

 17.9% 

OR

Skin-skin

 51.5 

(20.9) 

Txf

 0% 

Comp 

 0% 

Mesh 

 100% 

Concurre

nt 

19.4%

LOS (d)

 1.9 (0.9) 

Readmit 

 1.0% 

Reop 

 0.0% 

Comp 

 3.2% 

SSO

 0% 

Seroma/ 

Hematoma 

 1.1% 

Retention 

 2.1% 

Other 

0%

LOS (d)

 4.4 (3.6) 

Readmit 

 2.2% 

Reop 

 2.2% 

Comp 

 10.8% 

SSO

 3.2% 

Seroma/ 

Hematoma 

 2.2% 

Retention 

 1.1% 

Other 

4.3%

Open had 

more postop 

complications 

(p=0.047) 

Robot had 

longer OR 

time 

(p<0.001) 

Propensity 

matched for 

BMI >= 30 

group 

Kosturakis, 

201867

Robot vs open 

Retrospective 

US 

VA

1/na 

n 

N=200

N=100

Age 

 57.2 

(1.3) 

Male 

 100% 

BMI

 27.8 

(0.5) 

ASA

 35% 

Primary

 78% 

Unilater

al 

 41% 

Pain 

(scale) 

0

N=100

Age 

 63.5 

(1.1) 

Male 

 99% 

BMI

 26.2 

(0.5) 

ASA

 62% 

Primary

 87% 

Unilateral 

 93% 

Pain 

(scale) 

 0 

OR

 109.7 (3.6) 

Unilateral 

 90.5 (5.0) 

Bilateral 

 121.9 (4.9) 

Comp 

 0% 

Mesh 

 100% 

TAPP

 100% 

Concurrent 

9% 

OR

 83.7 

(2.6) 

Unilateral 

 80.2 

(2.2) 

Bilateral 

 121.5 

(18.3) 

Comp 

 0% 

Concurre

nt 

 5% 

ED

 6% 

Comp 

 21% 

SSO

 3% 

Pain 

(scale) 

 0 

Pain (visits) 

 0% 

Narcotic 

 5% 

Retention 

 18% 

Other 

 0% 

ED

 11% 

Comp 

 22% 

SSO

 7% 

Pain (scale) 

 0 

Pain (visits) 

 9% 

Narcotic 

 12% 

Retention 

 13% 

Other 

 2% 

Pain 

(referral)

 0% 

Recur 

 4%

Pain 

(referral

) 

 1% 

Recur 

 4%

OR times 

longer for 

robot 

(p<0.0001) 

More post-op 

visits for pain 

in open 

group 

(p=0.003) 

Kudsi, 201774

Robot vs lap 

Retrospective 

US 

1/1 

n 

N=275 

N=118

Age 

 58.8 

(15.4) 

Male 

 85.6% 

BMI

 28.4 

(5.0) 

ASA3 

 28.0% 

Elective 

 97.5% 

Primary

 93.2% 

Unilater

al

N=157

Age 

 55.1 

(14.8) 

Male 

 94.9% 

BMI

 27.1 (4.9) 

ASA3 

 19.9% 

Elective 

 99.4% 

Primary

 91.1% 

Unilateral 

 76.4% 

OR

Skin-skin

 69.1 (35.1) 

Unilateral 

 64.5 (35.6) 

Bilateral 

 80.2 (31.7) 

Comp 

 0 

Conversion 

 0% 

Mesh 

 100% 

TAPP

 100%

OR

Skin-Skin

 69.1 (26.3) 

Unilateral 

 63.3 (23.6) 

Bilateral 

 88.3 (26.1) 

Comp 

 0.6% 

Conversion 

 0.6% 

Mesh 

 100% 

TEP

 100%

Readmit

 3.4% 

Comp*

 6.8% 

SSO

 0% 

Seroma/ 

hematoma 

 1.7% 

Retention 

 1.7% 

Other 

 3.4%

Readmit

 1.9% 

Comp*

 5.1% 

SSO

 0% 

Seroma/ 

hematoma 

 1.9% 

Retention 

 1.3% 

Other 

 1.3%

1-yr F/U

85.6%

F/U

1 y

Pain**

0.8%

Recur

0%

1-yr

F/U

100%

F/U

1 y

Pain**

0.6%

Recur

0.6%

*

3-month

complications

**Inguinodyni

a 
Robot-assisted Procedures in General Surgery Evidence Synthesis Program

155

70.3%

Lammers, 201983

Robot vs lap vs

open 

Retrospective 

US 

1/na 

y 

N=277

BMI

 31 

BMI

 26 

BMI

 27 

OR

 146 

OR

 86 

OR

 75 

Readmit

0% 

Readmit

 1.2% 

Readmit

 2.4% 

F/U

 30 d 

F/U

 30 d 

F/U

 30 d 

Robot had 

significantly 

longer OR 

times 

(p<0.001) 

Higher 

readmission 

in open 

group 

(p=0.03)

Macias, 201781

Robot vs lap 

Retrospective 

US 

2/1 

n 

N=55

N=21 N=34 OR

 71.2 

OR

 54.2 

LOS (min)*

 113.4 

LOS (min)*

 144.4 

Pain**

 24%

Pain**

 3%

Mean OR 

time longer 

for robot 

(p=0.001) 

Higher 

prevalence of 

inguinodynia 

in robot 

group

*

Recovery

room time

**Inguinodyni

a 

Muysoms, 201873

Robot vs lap 

Prospective (lap 

data from 

previous 

published 

studies) 

Belgium 

1/1 

n 

N=112 

Pooled

N=49

Age 

 58.8 

Male 

 98.0% 

BMI

 25.0 

Unilater

al 

 69.4% 

QOL* 

 24 [14-

37] 

Pain 

 7 [4-13] 

N=63

Age 

 57.7 

Male 

 96.8% 

BMI

 24.4 

Unilateral 

 59.5% 

QOL* 

 17 [11-28] 

Pain 

 4 [2-9]

OR

Skin-skin

 61.3 

Room time 

 101.7 

Comp 

 0% 

Conversion 

 0% 

Mesh 

 100% 

TAPP

 100% 

OR

Skin-skin

 59.3 

Room time 

 95.1 

Comp 

 0% 

Conversion 

 0% 

Mesh 

 100% 

TAPP

 100% 

Comp

 24.5% 

Seroma/ 

hematoma 

 14.3% 

Retention 

 10.2% 

Comp

 15.9% 

Seroma/ 

hematoma 

 11.1% 

Retention 

 4.8% 

F/U (wk)

 4 

(100%) 

QOL** 

 4 [1-12] 

Pain: 

 1 [0-3] 

F/U 

(wk) 

 4 

(100%)

QOL**

 6 [3-

14], 

Pain: 

 2 [0-5] 

*EuraHS

**EuraHS 1

mo postop

Median [IQR] 

Examined 

learning 

curve (single 

surgeon 

without 

clinical 

experience 

with robot)

Muysoms, 201873

Robot vs lap 

Unilateral 

N=34

Age 

 60.4 

(16.5) 

Male 

 97.1% 

BMI

 25 (3.4) 

N=22

Age 

 59.0 

(11.8) 

Male 

 90.9% 

BMI

 24 (3.0) 

OR

Skin-skin

 54 (16) 

Room time 

 94 (17) 

Concurrent 

 3% 

OR

Skin-skin

 45 (11) 

Room time 

 79 (10) 

Concurrent 

 5% 

Comp

 23.5% 

Seroma/ 

hematoma 

 15% 

Retention 

 9% 

Comp

 9% 

Seroma/ 

hematoma 

 9% 

Retention 

0% 

Muysoms, 201873

Robot vs lap 

Bilateral 

N=15

Age 

 55.3 

(12.5)

N=41

Age 

 57.0 

Male

OR 

Skin-skin

 78 (16) 

Room time

OR 

Skin-skin

 67.0 

Room time

Comp

 26.6% 

Seroma/ 

hematoma

Comp

 19.5% 

Seroma/ 

hematoma
Robot-assisted Procedures in General Surgery Evidence Synthesis Program

156

Male

 100% 

BMI

 25 (2.1) 

Primary

86.7%

100%

BMI

 24.6 

Primary

 100% 

119 (15) 101.8 13.3%

Retention 

 13.3% 

12.2%

Retention 

 7.3% 

Pokala, 201982

Robot vs lap vs

open 

Prospective 

(Vizient) 

US 

na/na 

n 

N=3,547 

N=594

White 

 81.5% 

Black 

 9.4% 

Other 

 9.1% 

Male 

 95.3% 

Elective 

 100% 

N=540

White 

 77.0% 

Black 

 11.9% 

Other 

 11.1% 

Male 

 80.4% 

Elective 

 100% 

N=2413

White 

 75.8% 

Black 

 12.1% 

Other 

 12.2% 

Male 

 84.1% 

Elective 

 100% 

LOS (d)*

 1.8 [1.6] 

Readmit 

 0.8% 

Comp 

 0.7% 

SSI

 0.0% 

Narcotic**

 93.8% 

 (7.6, 1.5) 

Mortality 

 0.2% 

LOS (d)*

 2.2 [2.1] 

Readmit 

 2.2% 

Comp 

 4.4% 

SSI

 0.6% 

Narcotic**

 93.1% 

 (9.7, 1.7) 

Mortality 

 0.2% 

LOS*

 3.6 d [4.1] 

Readmit 

 3.6% 

Comp 

 3.9% 

SSI

 8.3% 

Narcotic**

 96.0% 

 (24.8, 2.3) 

Mortality 

 0.2% 

F/U

 30 d 

F/U

 30 d 

F/U

 30 d 

Overall 

complications 

lower for 

robot (p<0.05 

vs open and 

lap) 

Postop 

infection + 

LOS 

significantly 

higher in 

open (p<0.05 

for lap and 

robot) 

*

Median

[IQR]

**Pain

quantified by:

% patients

prescribed

opiates

(mean units

used, mean

days used)

Direct cost

9431 (5490)

vs 6502

(4005) vs

8837 (14353)

Open more 

expensive 

than lap 

(p<0.05) 

Robot more 

expensive 

than lap 

(p<0.05)

Prabhu 202063

Robot vs lap 

RCT 

US 

6/na 

n/a 

N=102 

N=48

Age: 

56.1 

(14.1) 

Race: 

83.3% 

white, 

4.2% 

Hispanic

, 10.4% 

AA, 0% 

Asian, 

2.1% 

other 

Male: 

91.6% 

BMI: 

24.9 

(3.24) 

DM: 

7.4% 

Tob: 

11.3%

N=54

Age: 57.2 

(13.3) 

Race: 

83.3% 

white, 

1.8% 

Hispanic, 

11.1% AA, 

1.8% 

Asian, 0% 

other 

Male: 

88.9% 

BMI: 26.9 

(4.42) 

DM: 4.2% 

Tob: 6.2% 

Primary: 

94.4% 

Unilateral: 

100% 

Pain*: 18.8

Skin-skin 

time: 75.5 

{59.0-93.8} 

Conversion 

to lap: 2.1%

TAPP: 

100% 

Skin-skin 

time: 40.5 

{29.2-63.8} 

TAPP: 

100% 

LOS (hrs): 

5.75 {5-7} 

Readmit: 4 

(8.3%)

Comp: 8 

(16.7%) 

SSI: 0% 

Seroma: 6 

(12.5%) 

Hematoma: 

1 (2.1%) 

Retention: 

1 (2.1%) 

1-w pain*:

+5.53

1-m pain*: -

7.00

LOS (hrs): 

5.11 {4-7} 

Readmit: 2 

(3.8%)

Comp: 5 

(9.3%) 

SSI: 2 

(3.7%) 

Seroma: 3 

(5.6%) 

Hematoma: 

0 (0%) 

Retention: 

1 (1.8%) 

1-w pain*:

+4.60

1-m pain*: -

7.92

F/U: 30 d

% F/U: 

93.8% 

F/U: 30 

d 

% F/U: 

98.1% 

Greater skinskin time in 

robot group 

(p<0.001) 

Similar LOS 

(p=0.424) 

readmission 

rate 

(p=0.420), 

and overall 

complication 

rate 

(p=0.374) 

No 

differences in 

change in 

VAS score 

from baseline 

at 1-week 

(p=0.86) and 

30-d (p-0.85)

{} = IQR

* Visual

Analog Scale

(VAS);

follow-up

pain

assessments

reflect score

change from

baseline
Robot-assisted Procedures in General Surgery Evidence Synthesis Program

157

Primary: 

89.4% 

Unilater

al: 100%

Pain*: 

15.2

Sheldon 201979

Robot vs lap vs

open 

Retrospective 

cohort 

US 

1/na 

n 

N=173 

N=49

Age: 

38.2 

(11) 

Male: 

87.8% 

Primary: 

100% 

Unilater

al: 

61.2% 

N=34

Age: 40.8 

(12) 

Male: 

91.2% 

Primary: 

100% 

Unilateral: 

58.9% 

N=90

Age: 39.7 

(14) 

Male: 

97.8% 

Primary: 

100% 

Unilateral

: 98.9% 

TAPP: 

100% 

TEP: 0% 

TAPP: 0%

TEP: 100% 

Mesh: 

100% 

Pain 

(MME): 

208.4 

(123.6) 

U/L: 205.4 

(139.5)

Narc: 

98.2% 

U/L: 96.7%

Pain 

(MME): 

229.4 

(126.2) 

 U/L: 198.7 

(116.1)

Narc: 

97.2% 

U/L: 95.0%

Pain (MME): 

230.4 

(122.3) 

U/L: 230.5 

(123.2)

Narc: 98.5% 

U/L: 97.8% 

F/U: 3 

mo

Repeat 

Rx: 8.2%

U/L: 

6.7%

F/U: 3 

mo

Repeat 

Rx: 

8.8%

U/L: 

5.0%

F/U: 3 

mo

Repeat 

Rx: 

10.0%

U/L: 

9.0%

Equal opioid 

use in all 

groups at 

discharge 

(p=0.962) 

and at followup requiring 

repeat Rx 

(p=0.935); 

same for 

lateralitycontrolled 

subanalysis 

(p=0.803 and 

p=0.807)

MME = 

morphine 

milligram 

equivalents 

Switzer, 201964

Robot vs lap 

Prospective 

(AHSQC) 

US 

na/na 

n 

N=148

N=33 

Elective 

 100% 

Unilater

al 

 100% 

Pain 

 10 

QOL*

 33 

(pain 10, 

restrictio

n 17, 

cosmeti

c 6)

N=115

Elective 

 100% 

Unilateral 

 100% 

Pain 

 6 

QOL*

 20 

(pain 6, 

restriction 

9, 

cosmetic 

5) 

Comp

 15% 

Comp

 9% 

F/U

 6 mo 

Readmit 

 3% 

Mesh inf 

 0% 

Pain 

 0

Recur 

 0% 

QOL*

 0 

F/U

 6 mo 

Readmi

t 

 0% 

Mesh 

inf 

 0% 

Pain 

 0

Recur 

 0% 

QOL*

 0 

No significant 

outcome 

differences 

*

EuraHS

score

Waite, 201665

Robot vs lap 

Retrospective 

US 

1/1 

n 

N=63 

N=39

Age*

 58.1 

{21-80} 

Male 

 97.4% 

BMI*

 27.5 

{23.0-

35.9} 

Unilater

al 

 74.4% 

N=24

Age*

 57.5 {43-

72} 

Male 

 100% 

BMI*

 27.6 

{21.0-33.3} 

Unilateral 

 75.0% 

OR

Skin-skin*

 77.5 {n/a} 

Unilateral 

 67.6 

Bilateral 

 106.2 

Room time 

 109.3 

Unilateral 

 100.0 

Bilateral 

 135.4 

Mesh 

 100% 

TAPP

100%

OR

Skin-skin*

 60.7 {45-

102} 

Unilateral 

 55.0 

Bilateral 

 77.8 

Room time 

 93.0 

Unilateral 

 87.7 

Bilateral 

 108.7 

Mesh 

 100% 

TAPP

LOS (min)

 218.4 

Unilateral 

 209.4 

Bilateral 

 244.4 

Pain**

 2.5 

Unilateral 

 2.2 

Bilateral 

 3.5

LOS (min)

 226.5 

Unilateral 

 216.3 

Bilateral 

 256.8 

Pain**

 3.8 

Unilateral 

 3.4 

Bilateral 

 5.1

Significantly 

longer OR 

time for 

robotic 

(p=0.001) 

Robotic 

surgery 

patients 

spent less 

time in 

recovery 

(p=0.033 for 

bilateral 

surgery, 

p=0.149 for 

unilateral 

*

Mean

{Range}

**Median of

scale (1-10)

Cost data 

(no sig diff) 

Ave direct 

cost: 3216 vs

3479 (lap vs

robot) 
Robot-assisted Procedures in General Surgery Evidence Synthesis Program

158

Concurrent

 12.8% 

100%

Concurrent 

 0% 

surgery) with 

less reported 

pain 

(p=0.062 for 

unilateral, 

p=0.090 for 

bilateral)

Zayan, 201976

Robot vs lap 

Retrospective 

US 

1/3 

n 

N=105 

N=37

Age 

 53.9 

(49.1– 

58.6) 

Male 

 100% 

BMI

 27.4 

(25.3– 

29.4) 

DM 

 5.4% 

Smoker 

 27.0% 

Elective 

 100% 

Primary

 81.1% 

Unilater

al 

 48.6% 

QOL*

 29.7 

(19.3– 

39.1)

N=68 

Age 

 52.7 

(49.2– 

56.1) 

Male 

 86.8% 

BMI

 26.1 

(25.1– 

27.1) 

DM 

 7.4% 

Smoker 

 11.8% 

Elective 

 100% 

Primary

 91.2% 

Unilateral 

 76.5% 

QOL*

 19.4 

(11.4– 

26.9) 

OR

 120 (105-

135) 

Mesh 

 100% 

TEP

 0% 

TAPP

 100% 

Concurrent 

 5.4% 

OR

 58 (54-63) 

Mesh 

 100% 

TEP

 52.9% 

TAPP

 47.1% 

Concurrent 

 0%

LOS (h)

 15.5 

(10.0– 

20.8) 

QOL*

 10.7 (2.1– 

18.3) 

LOS (h)

 9.6 (8.3–

11.0) 

QOL*

 10.2 (5.5– 

14.3) 

F/U (mo)

 14.1 

(13.1– 

15.0) 

Recur 

 0.0% 

QOL*

 8.4 

(2.6–

14.0) 

F/U 

(mo)

 15.5 

(14.7– 

16.3) 

Recur 

 5.9%

QOL*

 5.1 

(2.0–

7.4) 

Significantly 

longer OR 

time for 

robotic 

(p<0.001) 

*

Carolinas

Comfort

Scale (CCS)
Evidence Synthesis Program

159

Robot-assisted Procedures in General Surgery

VENTRAL HERNIA REPAIR 

Author, Year 

Population 

Study Design 

US (y/n) 

VA (y/n) 

#Institutions/

Surgeons 

Propensity 

Matching 

(y/n) 

Total N

Patient Characteristics 

Preop

Total N 

Age, mean yr (SD) 

Race/Ethnicity 

 NH-White, % 

 NH-Black, % 

 NH-Asian, % 

 NH-Other/Unknown, % 

 Hispanic, % 

Male, % 

BMI, mean (SD) 

ASA class, mean (SD) 

Diabetes, % 

Smokers, % 

Hernia characteristics 

 Elective surgery, N (%)

 Hernia area, cm2 (SD)

 Midline hernia, N (%) 

Recurrent hernia, N (%)

Intraoperative Outcomes

OR time, min (SD) 

EBL, mL (SD) 

Transfusions, % 

Complications, %

Conversion 

 To Open, %

 To Lap, % 

Mesh repair, % 

Fascial closure, % 

Concurrent procedure, % 

Short-Term Outcomes (<=30d)

Readmissions, N (%) 

Reoperations, N (%) 

ED visits, mean (SD) 

LOS, mean days (SD) 

Complications, N (%) 

 SSI, N (%) 

 SSO, N (%) 

 Seroma, N (%)

 Hematoma, N (%) 

 Enterotomy, N (%) 

 Pain, N (%) 

 Narcotic use, N (%) 

 Return to work, N (%) 

 Mortality, N (%) 

 Urinary retention, N (%) 

 Other, N (%) 

 Ileus, N (%) 

Long-Term Outcomes (>30d)

Follow-up at 1 year, % 

Length of follow-up, mean (SD) 

Readmissions, N (%) 

Mesh infection, N (%) 

Pain, N (%)

Recurrence, N (%) 

QOL

Primary MultiVariate FindingsComments

Robot Lap Open Robot Lap Open Robot Lap Open Robot Lap Open

Abdalla, 

201785

Robot vs lap 

VHR 

RCT 

N (Brazil)

N 

1/NR 

N 

N=38 

Abstract only

N=19 N=19 Mortality: 0 Mortality: 1 

(5.26%) 

F/U 

length: 

>1 yr

Recur: 2

(10.53%)

F/U 

length: >1 

yr 

Recur: 4 

(21.05%) 

Trend toward better 

QOL improvement 

and improved 

abdominal wall 

function in robot 

group 

Similar outcomes 

and morbidities 

Cost

Altieri, 201899

Robot vs lap 

VHR 

Prospective 

cohort (NY 

Statewide 

Planning and 

Research 

Cooperative 

System) 

Y 

N 

NR/NR

N=679

Race: 

75.11

% 

white, 

12.37

% AA, 

0.44% 

Asian, 

4.57% 

Hispan

ic, 

7.51% 

other

N=2089

6 

Race: 

65.12% 

white, 

12.79% 

AA, 

1.02% 

Asian, 

11.79% 

Hispani

c, 

9.28% 

other

Readmit: 

63 (9.28%) 

Reop: 

ED: 98 

(14.43%) 

LOS: 2.19 

(6.31) 

Complicati

on: 137 

(20.18%) 

Readmit: 

1058 

(5.06%) 

Reop: 

ED: 2185 

(10.46%) 

LOS: 4.32 

(18.04) 

Complicati

on: 2206 

(10.56%) 

F/U 

length: 

30 d 

F/U 

length: 30 

d 

Higher readmission 

(p<0.0001), ED 

revisit (p<0.0001), 

complication rate 

(p<0.0001), and 

longer LOS 

(p=0.0023) in robot 

group 
Robot-assisted Procedures in General Surgery Evidence Synthesis Program

160

Y (see row 

below) 

N=21575

Male: 

86.89

% 

BMI>3

0: 

25.77

% 

DM: 

19.00

%

Male: 

44.55% 

BMI>30

: 

11.27% 

DM: 

11.23% 

Altieri, 2018 

99

N=1356

Propensity 

score 

matched

N=678 N=678 Readmit: 

ED: 

LOS: 

Complicati

on: 

Readmit: 

ED: 

LOS: 

Complicati

on: 

Propensity score 

matched, no 

difference in 30-day 

readmission 

(p=0.2760), ED 

revisit (p=0.2043); 

shorter LOS (-1 

day, p<0.0001) and 

decreased 

complication rate (-

0.0575 risk 

difference, CI -

0.1023- -0.0128, 

p=0.0134)

Armijo, 

2018104

Robot vs lap 

vs open VHR 

Prospective 

cohort 

(Vizient) 

Y 

N 

NR/NR 

N 

N=46799 

N=465

Age: 

59 

(13.1) 

Male: 

40.2% 

ASA: 

NR 

(“major

” 

illness: 

15.3%) 

N=6829

Age: 57 

(13.2) 

Male: 

60.8% 

ASA: 

NR 

(“major” 

illness: 

6.9%) 

N=3950

5 

Age: 57 

(13.3) 

Male: 

58.3% 

ASA: 

NR 

(“major” 

illness: 

18.8%) 

Readmit: 

3.87%, CI 

2.31-6.05 

LOS: 2 

(IQR 1-4)

Complicati

on: 7.3%, 

CI 5.1-

10.0 

SSI*: 

1.72%, CI 

0.75-3.36 

Narc**: 

95.8%, 

19.5, 2.8 

Mortality: 

0.43%, CI 

0.05-1.54 

Readmit: 

2.86%, CI 

2.47-3.28 

LOS: 3 

(IQR 2-4)

Complicati

on: 3.5%, 

CI 3.1-4.0 

SSI*: 

0.67%, CI 

0.49-0.90 

Narc**: 

96.3%, 

20.8, 2.6 

Mortality: 

0.16%, CI 

0.08-0.29 

Readmit: 

7.55%, CI 

7.29-7.81 

LOS: 5 

(IQR 3-8)

Complicatio

n: 11.4%, 

CI 11.1-

11.75 

SSI*: 

2.83%, CI 

2.67-3.00 

Narc**: 

95.7%, 

52.7, 4.8 

Mortality: 

0.99%, CI 

0.90-1.1 

F/U 

length: 

30 d 

F/U 

length: 30 

d 

F/U 

length: 30 

d 

Open group highest 

rate of 

complications, then 

robot, then lap 

(p<0.01) 

Highest mortality in 

open group vs lap 

(p<0.05) 

Lowest post-op 

infection rate in lap 

vs open and robot 

(p<0.05) 

Longer LOS for 

open patients 

(p<0.05), no 

difference lap vs 

robot 

No difference in 

opiate Rx, however

higher units used 

and longer duration 

in open group

Cost

*”postoperative 

infection” 

interpreted as SSI 

**narcotic use 

assessed by % 

patients prescribed 

opiates, mean 

resource units 

used/case (units), 

and mean days of 

resource units 

used/case (days) 

Bittner, 

201886

N=26 N=76 OR time: 

365 (78) 

OR time: 

287 (121) 

Readmit: 

7.7% 

Readmit: 

6.6% 

F/U 

length: 

90 days 

F/U 

length: 90 

days

r-TAR decreased

mean hospital LOS

by 3 days (p<0.01)

*Post-op

complications up to

90 days post-op
Robot-assisted Procedures in General Surgery Evidence Synthesis Program

161

Robot vs 

open TAR + 

VHR 

Retrospectiv

e cohort 

(prospective 

data) 

Y 

N 

1/1 

N 

N=102 

Age: 

52.4 

(12.9) 

Male: 

33.3% 

BMI: 

33.4 

(9)

ASA: 3

DM: 

0% 

Tob: 

0% 

Electiv

e: 

100% 

Size 

(area): 

235 

(107) 

[length: 

18.5 

(5.1), 

width: 

12.3 

(3)]

Midline

: 83% 

Recurr

ent: 

58.3%

Age: 

54.6 

(14) 

Male: 

46% 

BMI: 

32.1 (7)

ASA: 3

DM: 

22.3% 

Tob: 

13% 

Elective

: 100% 

Size 

(area): 

260 

(209) 

[length: 

17.1 

(7.1), 

width: 

13.7 

(5.9)] 

Midline: 

89.5% 

Recurre

nt: 

52.6% 

Complica

tion: 0% 

Conversi

on: 0% 

Mesh: 

100% 

Closure: 

100% 

Concurre

nt: 0% 

Complica

tion: 

5.3% 

Mesh: 

100% 

Closure: 

100%

Concurre

nt: 16% 

LOS: 3.8 

(1.5) 

Complicati

on: 19.2%* 

SSI: 0%

Seroma/ 

hematoma

: 1 (3.8%) 

Mortality: 

0% 

Retention: 

2 (7.69%) 

Other: 1 

(3.85%) 

Ileus: 1 

(3.85%) 

LOS: 7.1 

(5.4) 

Complicatio

n: 30.2%* 

SSI: 2 

(2.6%) 

Seroma/ 

hematoma: 

0 

Mortality: 

0% 

Retention: 6 

(7.89%) 

Other: 25 

(32.89%) 

Ileus: 1 

(1.32%) 

Longer OR times in 

r-TAR group

(p<0.01)

Similar complication

rates (p=0.09)

Carbonell, 

201890

Robot vs 

open VHR 

(TAR 

permitted) 

Prospective 

cohort 

(AHSQC) 

Y 

N 

219/181 (14 

robot, 39 

open after 

matching) 

Y 

N=1205 (333 

matched) 

N=111

Age: 

55.59 

(12.36) 

Race: 

86% 

white 

Male: 

39% 

BMI: 

33.88 

(7.30) 

ASA: 

2.60 

DM: 

25% 

Tob: 

22% 

Electiv

e: 

100% 

Size: 

87.96 

N=222

Age: 

55.08 

(13.76) 

Race: 

82% 

white 

Male: 

43% 

BMI: 

33.23 

(7.39) 

ASA: 

2.62 

DM: 

25% 

Tob: 

20% 

Elective

: 100% 

Size: 

80.13 

cm2

OR time 

>2h:

45.05%

Complica

tion: 2

(1.80%)

Conversi

on:

3.60% to

open

Mesh:

100%

Closure:

100%

Concurre

nt: 0%

TAR:

85%

OR time 

>2h:

12.61%

Complica

tion: 3

(1.35%)

Mesh:

100%

Closure:

99%

Concurre

nt: 0%

TAR:

83%

Readmit: 

6% 

Reop: 2% 

LOS: 2 

(IQR 2)

Complicati

on: 66 

(29.71%)

SSI: 2% 

SSO: 32% 

Seroma/ 

hematoma

: 31 

(27.93%) 

Enterotom

y: 2 

(1.80%) 

[+1 

(0.90%) 

gastric 

injury] 

Pain: 1 

(0.90%, 

Readmit: 

5% 

Reop: 3% 

LOS: 3 

(IQR 3)

Complicatio

n: 48 

(43.24%) 

SSI: 4% 

SSO: 14% 

Seroma/ 

hematoma: 

11 (4.95%) 

Enterotomy: 

3 (1.35%) 

Pain: 1 

(0.45%, 

readmission

) 

Mortality: 2 

(0.90%) 

F/U 

length: 

30 d 

F/U 

length: 30 

d 

Shorter OR times 

with open repair 

(p<0.001) 

Decreased LOS 

with robot VHR 

(p<0.001) 

No difference in 

intraop 

complications 

(p=1), reoperations, 

readmissions, or 

SSIs, but higher 

proportion of robot 

patients 

experienced SSOs 

(p<0.001), mostly 

seromas (p<0.001) 

First author and 

several others 

received honoraria 

or grants from 

Intuitive 

Robotic data 

overlaps with 

Warren, 2016 
Robot-assisted Procedures in General Surgery Evidence Synthesis Program

162

cm2

(67.57)

, width 

7.51 

(3.34), 

length 

13.17 

(6.58) 

Recurr

ent: 

38%

(74.02), 

width 

7.17 

(3.68), 

length 

12.00 

(6.89) 

Recurre

nt: 37% 

readmissio

n) 

Mortality: 0 

Chen, 

2016100

Robot vs lap 

VHR 

Retrospectiv

e cohort 

Y 

N 

1/3 

N 

N=72 

N=39

Age: 

47.2 

{24-69} 

Male: 

43.6% 

BMI: 

33 {23-

53} 

ASA: 

2.15 

DM: 

12.82

% 

Size: 

3.07 

cm {1-

9} 

Recurr

ent: 

10.26

%

N=33

Age: 

46.6 

{27-68} 

Male: 

72.7% 

BMI: 32 

{25-45} 

ASA: 

1.97 

DM: 

15.15% 

Size: 

2.02 cm 

{0.5-5}

Recurre

nt: 

9.09% 

OR time: 

156.6 

{77-261} 

Mesh: 

100% 

Closure: 

7.69%

OR time: 

65.9 {25-

128} 

Mesh: 

100% 

Closure: 

0 

LOS: 0.49 

{0-3} (for 

N=14) 

Complicati

on: 3 

(7.7%) 

SSI: 0 

Seroma/ 

hematoma

: 1 (2.56%) 

Retention: 

2 (5.13%) 

LOS: 0.21 

{0-1} (for 

N=7) 

Complicati

on: 3 

(9.1%) 

SSI: 1 

(3.03%) 

Seroma/ 

hematoma

: 1 (3.03%) 

Retention: 

1 (3.03%) 

F/U 

length: 

47 d 

Recur*: 

0 

F/U 

length: 47 

d 

Recur*: 0 

Longer operative 

time in robot group 

(p<0.0001) 

Larger hernia sizes 

in robot group 

(p<0.0001) 

No difference in 

LOS for those who 

stayed (p=0.09) 

No difference in 

complications (p=1) 

{}=range

*30-d recurrence

Coakley, 

201798

Robot vs lap 

VHR 

Prospective 

cohort 

(HCUP-NIS) 

Y 

N 

NR/NR 

N 

N=32594 

N=351

Age: 

59.4 

(14.6) 

Race: 

73% 

white, 

11.3 

AA, 

9.5% 

Hispan

ic, 

6.2% 

other 

Male: 

48% 

BMI>3

0: 

20.5% 

N=3224

3 

Age: 

57.4 

(14.9) 

Race: 

75.3%

white, 

10.5% 

AA, 

10.1% 

Hispani

c, 4.1% 

other 

Male: 

43% 

BMI>30

: 25.3% 

ASA: 

NR [CCI 

Concurre

nt: 0% 

Concurre

nt: 0% 

LOS: 3.5 

(3.6) 

Complicati

on: 

20.24% 

SSI: 

0.85% 

SSO:

0.28% 

Mortality: 

0% 

Other: 

13.7% 

Ileus: 

5.41% 

LOS: 3.4 

(2.6) 

Complicati

on: 

18.73% 

SSI: 

0.47% 

SSO:

0.07% 

Mortality: 

0.1% 

Other: 

9.75% 

Ileus: 

8.34% 

No difference 

between LOS 

(p=0.2), minor or 

major complication 

rates (p=0.858, 

p=0.226), mortality 

(p=0.478) 

Cost/utilization

CCI = Charlson 

comorbidity index 
Robot-assisted Procedures in General Surgery Evidence Synthesis Program

163

ASA: 

NR 

[CCI 

1.1 

(1.7)] 

DM: 

18.0% 

Electiv

e: 

100% 

0.83 

(1.3)] 

DM: 

22.2% 

Elective

: 100% 

Gonzalez, 

201595

Robot vs lap 

VHR 

Retrospectiv

e cohort 

Y 

N 

1/2 

N 

N=134 

N=67

Age: 

56.6 

(14.5) 

Male: 

38.8% 

BMI: 

34.7 

(9.0) 

ASA: 

2.2 

(0.7) 

Midline

: 

65.6% 

N=67

Age: 

55.0 

(13.2) 

Male: 

31.4% 

BMI: 

33.5 

(9.5) 

ASA: 

2.0 (0.8) 

Midline: 

74.6% 

Skin-skin 

time: 

107.6 

(33.9) 

Conversi

on: 1 

(1.5%) to 

open

Mesh: 

100% 

Closure: 

100% 

Concurre

nt: 3.0% 

Skin-skin 

time: 

87.9 

(53.1) 

Conversi

on: 3 

(4.5%) to 

open

Mesh: 

100% 

Closure: 

0% 

Concurre

nt: 4.5% 

Reop: 1 

(1.5%)* 

LOS: 2.5 

(4.1) 

Complicati

on: 2 

(3.0%) 

SSO: NR 

Seroma/ 

hematoma

: NR 

Enterotom

y: NR 

Mortality: 

0% 

Other: 1 

(1.5%) 

Reop: 2 

(3.0%) 

LOS: 3.7 

(6.6) 

Complicati

on: 7 

(10.4%) 

SSI: 2 

(3.0%) 

Seroma/ 

hematoma

: 2 (3.0%) 

Enterotom

y: 1 (1.5%) 

Mortality: 

0% 

Other: 2 

(3.0%) 

1-yr F/U:

NR

F/U

length:

17.1 mo

(9.5)

Mesh

infxn: 1

(1.5%)

Recur: 1

(1.5%)

1-yr F/U:

NR

F/U

length:

21.7 mo

(12.1)

Mesh

infxn: NR

Recur: 5

(7.5%)

Longer surgical 

time for PCD (robot) 

by 19.7 (p=0.012) 

Longer follow-up for

NPCD (lap) by 4.6 

mo (p=0.016) 

Trend toward 

increased 

complications 

(p=0.084) and 

recurrences 

(p=0.095) in NPCD 

(lap) 

No difference in 

LOS (p=0.461) or 

rate of conversion 

(p=0.310)

*SBO requiring

reoperation 4 mo

post-op

PCD vs non-PCD 

associated with 

robot vs lap 

GuzmanPruneda, 

2020 (#1457) 

Robot vs

open VHR + 

CS

Prospective 

database 

(AHSQC) 

Y 

N 

NR/303 

N 

N=236

N=42

Age: 

59 {54-

65} 

Male: 

36% 

BMI: 

32 {28-

39} 

ASA: 

2.60 

DM: 

19% 

Tob: 

14% 

Electiv

e: 

100% 

Area: 

61 {40-

120}; 

length 

N=194

Age: 62 

{53-68} 

Male: 

57% 

BMI: 31 

{28-35} 

ASA: 

2.73 

DM: 

22% 

Tob: 3% 

Elective

: 100% 

Area: 

193 

{106-

300}; 

length 

19 {15-

25}; 

OR time 

>240:

33%

Comp:

0%

Conversi

on to

open:

7.1%

Mesh:

100%

OR time 

>240:

18%

Comp:

0%

Mesh:

100%

Readmit: 1 

(2%)

Reop: 1 

(2%)

LOS: 1.5 

{1-2.8} 

Comp: 4 

(9.5%) 

SSI: 0 

(0%)

SSO: 3 

(7.1%) 

Seroma: 2 

(4.8%) 

Hematoma

: 1 (2.4%) 

Other: 1 

(2.4%) 

QOL: 50 

{35-59} 

Readmit: 13 

(7%)

Reop: 3 

(2%)

LOS: 5 {4-

6} 

Comp: 30 

(15.5%) 

SSI: 3 

(1.5%) 

SSO: 17 

(8.8%) 

 Seroma: 5 

(2.6%) 

Hematoma: 

2 (1.5%) 

Other: 10 

(5.2%) 

QOL: 46 

{28-72} 

1-yr F/U:

100%

Recur:

10 (24%)

QOL: 90

{58-94}

1-yr F/U:

100%

Recur: 38

(20%)

QOL: 88

{67-93}

Significantly shorter 

LOS with robot 

(p<0.01) 

Otherwise no 

significant 

differences 

between robot and 

open approaches 

for QOL (p=0.66), 

wound morbidity 

(p=0.53), 

readmission 

(p=0.36), or 

recurrence (p=0.28)

{}=IQR

*Only patients with

1 or fewer hernia

recurrences

included

QOL described by 

HerQLes score 
Robot-assisted Procedures in General Surgery Evidence Synthesis Program

164

13 {8-

19}; 

width 7 

{5.2-

8.8} 

Recur*

: 33% 

QOL: 

38 {20-

67}

width 13 

{9-16} 

Recur*: 

31% 

QOL: 

43 {20-

67}

Khorgami, 

201894

Robot vs lap 

VHR 

Prospective 

cohort 

(HCUP-NIS, 

AHRQ) 

Y 

N 

NR/NR 

N 

N=3699

N=99 N=3600 Concurre

nt: 0% 

Concurre

nt: 0% 

LOS: 2.9 

(3.1) 

LOS: 2.7 

(1.9) 

Cost

Data pooled into 

robot vs lap for 

multiple procedures 

(chole, VHR, 

colectomies, 

sigmoidectomy, 

APR, TAH) – no 

subgroup analyses 

for outcomes 

Lu, 2019 

(#1479) 

Robot vs lap 

VHR 

Retrospectiv

e cohort 

Y 

N 

1/NR 

N 

N=206

N=86

Age: 

50.8 

(12.8) 

Male: 

47.6% 

BMI: 

34.4 

(7.4) 

ASA: 

2.4 

(0.52) 

DM: 

19.8% 

Size: 

7.1 

(2.6) 

Recur: 

18.6% 

N=120

Age: 

53.2 

(14.6) 

Male: 

61.7% 

BMI: 

31.3 

(6.1) 

ASA: 

2.1 

(0.52) 

DM: 

8.3% 

Size: 

5.5 (1.8) 

Recur: 

18.3% 

OR time: 

174.7 

(44.9) 

Mesh: 

100% 

OR time: 

120.4 

(35.0) 

Mesh: 

100% 

Readmit: 2 

(2.3%) 

Reop: 2 

(2.3%) 

LOS: 0.1 

(0.5) 

Comp: 2 

(2.3%) 

SSO: 2 

(2.3%) 

Seroma: 0 

(0%)

Hematoma

: 1 (1.2%) 

Other: 0 

(0%)

Readmit: 3 

(2.5%) 

Reop: 3 

(2.5%) 

LOS: 0.2 

(0.9) 

Comp: 11 

(9.2%) 

SSO: 6 

(6.7%) 

Seroma: 4 

(3.3%) 

Hematoma

: 2 (1.7%) 

Other: 3 

(2.5%) 

1-yr F/U:

73.8%

F/U: 5.5

mo (5.9)

Recur: 1

(1.2%)

1-yr F/U:

33.3%

F/U: 5.7

mo (4.9)

Recur: 2

(1.7%)

Longer OR times in 

robot group 

(p<0.001) 

Higher rate of 

complications with 

lap (p=0.046) 

No significant 

differences for LOS 

(p=0.294), 

reoperation 

(p=0.938), 

readmission 

(p=0.938), and 

recurrence 

(p=0.771) 

In a subgroup 

analysis of patients 

(n=71) with at least 

12-mo follow-up,

there was no

difference in

complications or

recurrence

QOL described by 

Carolina Comfort 

Scale (CCS) 
Robot-assisted Procedures in General Surgery Evidence Synthesis Program

165

Martin-delCampo, 

201887

Robot vs 

open TAR + 

VHR 

Retrospectiv

e cohort 

Y 

N 

2/NR 

Y (defect 

size)

N=114 

N=38

Age: 

58.9 

(12.7) 

Male: 

39.5% 

BMI: 

33.1 

(8.8) 

ASA3

: 50% 

DM: 

18.4% 

Tob: 

15.8% 

Electiv

e: 

100% 

Size 

(width): 

13.5 

(4.5) 

Recurr

ent: 

28.9%

N=76

Age: 

58.8 

(11.8) 

Male: 

32.9% 

BMI: 

33.51 

(5.7) 

ASA3: 

75% 

DM: 

22.3% 

Tob: 

9.2% 

Elective

: 100% 

Size 

(width): 

13.5 

(4.5) 

Recurre

nt: 

64.5% 

OR time: 

299 (95) 

EBL: 49 

(60) 

Transfxn: 

0% 

Complica

tion: 0% 

Conversi

on: NR 

Mesh: 

100% 

OR time: 

211 (63) 

EBL: 139 

(149) 

Transfxn: 

6.57%* 

Complica

tion: 0% 

Mesh: 

100% 

Readmit: 

0% 

LOS: 1.3 

(1.3) 

Complicati

on: 0% 

SSO: 1 

(2.6%) 

Mortality: 

0% 

Other: 0% 

Ileus: 0% 

Readmit: 2 

(2.64%) 

LOS: 6 

(3.4) 

Complicatio

n: 13 

(17.1%) 

SSO: 9 

(11.8%) 

Mortality: 

0% 

Other: 10 

(13.15%) 

Ileus: 3 

(3.95%) 

Longer OR times 

for r-TAR (p<0.001)

Lower EBL for rTAR (p<0.001) 

No difference 

between in-hospital 

transfusions 

(p=0.106) 

Higher rate of 

systemic 

complications with 

o-TAR (p=0.007)

No difference in

wound morbidity

(p=0.101)

Shorter hospital

stay in r-TAR

(p<0.001)

*Post-op

transfusion

Mudyanadzo, 

2020 (#1503)

Robot vs lap 

VHR 

Retrospectiv

e cohort 

Y 

N 

1/NR 

N 

N=35

N=16

Electiv

e: 

100% 

Recur: 

0% 

N=19

Elective

: 100% 

Recur: 

0% 

LOS: 1.3 

(0.1) 

Pain*: 1 

(6.2%)

Narc**: 4.2 

(4.25) 

LOS: 1.7 

(0.2) 

Pain*: 6 

(31.6%)

Narc**: 

14.5 

(5.218) 

F/U: 8 w F/U: 8 w Similar LOS 

between groups (p 

n.s.)

Decreased pain in 

robot group 

(p<0.05) 

Increased narcotic 

use in lap group 

(p<0.05) 

*Pain measured as

requiring additional

narcotics within

follow-up period

**Narcotic use 

defined as daily 

opioid use 

(morphine 

equivalents) 

Nguyen, 

201788

Robot vs 

open TAR + 

VHR 

Retrospectiv

e cohort 

Y 

N 

1/1 

N 

N=27

Age: 

55.4 

(12.4) 

BMI: 

32.2 

(6.4) 

Size 

(area): 

216 

N=16

Age: 

58.6 

(10.4) 

BMI: 

33.3 

(5.5) 

Size 

(area): 

242 

OR time: 

272.1 

EBL: 43 

Mesh: 

100%

OR time: 

206.5 

EBL: 

146.9 

Mesh: 

NR 

Readmit: 

0% 

Reop: 0% 

ED: 4 

(14.81%) 

LOS: 3.0 

SSO: 1 

(3.70%) 

Seroma/ 

hematoma

: NR 

Other: NR 

Readmit: 2 

(12.5%) 

Reop: 2 

(12.5%)

ED: 4 

(25%) 

LOS: 9.6 

SSO: 3 

(18.75%) 

Seroma/ 

hematoma: 

1 (6.25%) 

Other: 4 

(25%)

Decreased LOS 

(p<0.001) and EBL 

(p<0.001) for RAR 

Longer OR times 

for RAR (p<0.001) 

OAR patients more 

likely to be admitted 

(p=0.132) and 

undergo 

reoperation 
Robot-assisted Procedures in General Surgery Evidence Synthesis Program

166

N=43

Abstract only

Prabhu, 

201796

Robot vs lap 

VHR 

Prospective 

cohort 

(AHSQC) 

Y 

N 

181/100 (40 

robot, 79 lap) 

Y 

N=1103 (638 

matched for 

fascial 

closure) 

N=200 

(186 

matche

d) 

Age: 

59 {48-

68}

Race: 

85% 

white 

Male: 

41% 

BMI: 

32 {28-

36} 

ASA 

(2): 

47% 

DM: 

19% 

Tob: 

17% 

Electiv

e: 

100% 

Size: 

19 cm2

{7-47} 

(width 

4 cm 

{3-6}, 

length 

6 cm 

{3-11})

Recurr

ent: 

33%

N=903 

(452 

matche

d) 

Age: 59 

{48-68}

Race: 

84% 

white 

Male: 

41% 

BMI: 32 

{28-37} 

ASA 

(2): 

47% 

DM: 

19% 

Tob: 

15% 

Elective

: 100% 

Size: 16 

cm2 {7-

38} 

(width 4 

cm {3-

6}, 

length 5 

cm {3-

8})

Recurre

nt: 31% 

OR time 

>2h: 46%

Transfxn:

1

(0.54%)

Complica

tion: 4

(2.15%)

Mesh:

100%

Closure:

91%

OR time 

>2h: 30%

Transfxn:

0

Complica

tion: 4

(0.88%)

Mesh:

100%

Closure:

90%

Readmit: 5 

(2.69%) 

Reop: 0 

LOS: 0 

(IQR 2.00)

Complicati

on: 14 

(8%)

SSI: 1% 

SSO: 5% 

Seroma/ 

hematoma

: 4% 

Enterotom

y: 0 

Pain: 1 

(0.54%) 

Mortality: 1 

(0.54%) 

Other: 2 

(1.08%) 

Ileus: 1 

(0.54%) 

Readmit: 

19 (4.20%) 

Reop: 8 

(1.77%)

LOS: 1 

(IQR 2.00)

Complicati

on: 84 

(19%) 

SSI: 1% 

SSO: 12% 

Seroma/ 

hematoma

: 10% 

Enterotom

y: 4 

(0.88%) 

Pain: 2 

(0.44%) 

Mortality: 0 

Other: 19 

(4.20%) 

Ileus: 8 

(1.77%) 

F/U 

length: 

30 d 

F/U 

length:30 

d 

Higher rate of 

fascial closure in 

robot group (93% 

vs 56%, p<0.05) 

Post-hoc analysis 

(N=638, matched 

for fascial closure), 

hernia length was 

longer (p=0.01) and 

OR time was longer 

(p<0.001) in robot 

group; increased 

SSO (p=0.006) or 

any complication 

(p<0.001) in lap 

group 

Increased LOS in 

lap group (p<0.001) 

without difference in 

readmission (p=0.4) 

or reoperation 

(p=0.1128) 

First author 

received grant 

money from 

Intuitive 

{}=range

Roberts, 

2019 (#1585) 

Robot vs

open VHR + 

TAR

Prospective 

database 

(AHSQC) 

Y 

N 

1/NR 

N=13

Area: 

87.4 

N=12

Area: 

175.9 

OR time: 

297.9 

Conversi

on to 

open: 

7.7% 

OR time: 

267.8 

LOS: 1.67

Seroma: 1 

(7.7%) 

Hematoma

: 1 (7.7%) 

Pain*: 0 

(0%)

LOS: 6.5

Seroma: 10 

(8.3%) 

Hematoma: 

10 (8.3%) 

Pain*: 3 

(25%) 

No difference in OR 

time (p=0.47) or 

hematoma/seroma 

(p=0.95) 

Decreased LOS for 

robot (p<0.0001) 

Trend toward 

decreased 

readmission for 

pain in robot group 

(p=0.0546)

*Pain defined as

30-day readmission

due to pain
Robot-assisted Procedures in General Surgery Evidence Synthesis Program

167

N

N=25 

Abstract only

Song, 

2017103

Robot vs lap 

vs open VHR 

Retrospectiv

e cohort 

Y 

N 

NR/NR 

(Premier 

Perspective 

Database) 

Y 

N=6642 

(N=286 

matched) 

Abstract only 

N=96 

matche

d vs 

open 

(N=94 

matche

d vs 

lap) 

Electiv

e: 

100% 

N=1992 

(N=94 

matche

d) 

Elective

: 100% 

N=4354 

(N=96 

matche

d) 

Elective

: 100% 

OR time: 

231 (101) 

Transfxn: 

0% 

Complica

tion: 1 

(1.0%) 

Conversi

on: 2 

(2.1%) 

OR time: 

169 (108) 

Transfxn: 

5 (5.3%)

Complica

tion: 4 

(4.3%) 

Conversi

on: 13 

(13.9%) 

OR time: 

163 (101) 

Transfxn: 

5 (5.2%) 

Complica

tion: 1 

(1.0%) 

LOS: 3.0 

(2.4) 

Complicati

on: 17 

(17.7%) 

SSO: 0% 

Seroma/ 

hematoma

: 0% 

Narc*: 48 

(30, 96) 

LOS: 3.2 

(3.0) 

Complicati

on: 23 

(24.5%) 

SSO: 0% 

Seroma/ 

hematoma

: 3 (3.2%) 

Narc*: 60 

(30, 60) 

LOS: 5.3 

(5.2) 

Complicatio

n: 38 

(39.6%) 

SSO: 3 

(3.1%) 

Seroma/ 

hematoma: 

4 (4.2%) 

Narc*: 93 

(48, 159) 

Mesh 

infxn: 0% 

Mesh 

infxn: 0% 

Mesh 

infxn: 0% 

Lower 

complications 

RVHR compared to 

OVHR (p=0.001), 

Fewer blood 

transfusions in 

RVHR compared to 

LVHR and OVHR 

(p=0.02) 

Fewer conver. 

compared to LVHR 

(p=0.003) 

Less in-hospital 

PCA compared to 

OVHR (p=0.02)

Shorter LOS 

compared to OVHR 

(p=0.003) 

Longer OR time 

compared to LVHR 

and OVHR 

(p<0.0001)

Obese patients only 

(BMI>30) 

Cost analysis 

*In-hospital PCA

morphine

equivalent dosage

(Q1, Q3)

Switzer, 

201789

Robot vs 

open VHR 

Prospective 

cohort 

(AHSQC) 

Y 

N 

NR/NR 

Y 

N=120 

Abstract only

N=30

Age: 

58 

(IQR 

51-63)

Male:

27%

Size

(width):

7 cm

N=90

Age: 61 

(IQR 

52-68)

Male:

31%

Size

(width):

6 cm

Readmit: 

3% 

Complicati

ons: NR 

HerQLes: 

48 

Readmit: 

3% 

Complicatio

ns: NR 

HerQLes: 

48 

F/U: 1 yr

Recur: 

23% 

QOL 

(HerQLe

s): 82 

F/U: 1 yr

Recur: 

19% 

QOL 

(HerQLes)

: 81 

Similar complication 

rates (p=0.29) 

No significant 

difference in 1-year 

recurrence (p=0.6)

Improved QOL 

outcomes in both 

robotic and open 

repairs without 

major differences at 

30 days (p=0.54) or 

1 year (p=0.86) 

Walker, 

201897

Robot vs lap 

VHR 

Retrospectiv

e cohort 

Y 

N 

N=142

Age: 

53.2 

(13.2) 

Male: 

50.0% 

BMI: 

31.6 

(5.1)

N=73

Age: 

49.5 

(13.3) 

Male: 

32.8% 

BMI: 

35.7 

(7.9)

Skin-skin 

time: 

116.9 

(47.9) 

Conversi

on: 

Mesh: 

100%

Skin-skin 

time: 

98.7 

(56.6) 

Conversi

on: 

Mesh: 

100%

LOS: 1.4 

(0.4) 

SSI: 0 

SSO: 24 

(16.9%) 

Seroma/ 

hematoma

: 13 (9.1%)

LOS: 0.7 

(0.3) 

SSI: 5 

(6.8%) 

SSO: 24 

(32.8%) 

Seroma/ 

F/U 

length: 

12.3 w 

(2.6) 

Recur: 

11 

(7.7%) 

F/U 

length: 

23.6 w 

(8.4) 

Recur: 5 

(6.8%) 

Fascial closure 

more often with 

robot (p=0.05) 

Shorter OR times 

with lap (p=0.03)

No difference in 

recurrence (p=1)

Robot had 

decreased SSO 
Robot-assisted Procedures in General Surgery Evidence Synthesis Program

168

2/10

Y (see row 

below) 

N=215 

ASA: 

2.5 

(0.7) 

DM: 

13.3% 

Tob: 

31.0% 

Electiv

e: 

100% 

Size: 

horizon

tal 4.3 

cm 

(3.2) 

Recurr

ent: 

35.2%

ASA: 

2.6 (0.7) 

DM: 

19.2% 

Tob: 

38.4% 

Elective

: 100% 

Size: 

horizont

al 4.1 

cm (2.1) 

Recurre

nt: 

34.2% 

Closure: 

71.1% 

Concurre

nt: 0% 

Closure: 

54.8% 

Concurre

nt: 0% 

hematoma

: 14 

(19.2%) 

(p=0.01), seromas 

(p=0.02), and SSI 

(p<0.01) 

Robot had 

decreased SO on 

multivariable 

analysis (OR 0.23, 

CI 0.08-0.67) 

Walker, 

201897

Propensity 

score 

matched 

N=96 

N=48 N=48 Closure: 

77% 

Closure: 

67% 

SSO: 

4.2% 

SSO: 

18.8% 

F/U: 4.9 

w (IQR 

2.0-11.5) 

Recur: 

2.1% 

F/U: 6.0 w 

(IQR 3.9-

9.4) 

Recur: 

4.2% 

Propensity score 

matched analysis: 

robot had increased 

rates of fascial 

closure (p<0.01), 

decreased SSO 

(p<0.001), 

decreased 

recurrence (p<0.01)

Warren, 

2016101

Robot vs lap 

VHR (TAR 

permitted) 

Prospective 

cohort 

(AHSQC) 

Y 

N 

1/NR 

N 

N=156 

N=53

Age: 

52.9 

(12.3) 

Race: 

84.91

% 

white, 

7.55% 

black, 

7.55% 

other 

Male: 

41.51

% 

BMI: 

34.7 

(7.4) 

ASA: 

2.64 

DM: 

28.3% 

Tob: 

24.53

% 

N=103

Age: 

60.2 

(13.4) 

Race: 

85.44% 

white, 

11.65% 

black, 

2.91% 

other 

Male: 

26.21% 

BMI: 

35.7 

(9.5) 

ASA: 

2.61 

DM: 

33.01% 

Tob: 

16.5% 

Size: 

88.0 

cm2

(94.0), 

OR time: 

245.6 

(98.5) 

Complica

tion: 1 

(1.89%)

Conversi

on: 0 

Mesh: 

Closure: 

96.23% 

Concurre

nt: 

TAR: 

43.4% 

OR time: 

121.5 

(57.2) 

Complica

tion: 9 

(8.74%)

Conversi

on: 

3.88% to 

open 

Mesh: 

97.09% 

Closure: 

50.49% 

Concurre

nt: 

TAR: 0% 

Readmit: 4 

(7.5%) 

Reop: 2 

(3.77%)

LOS: 1 {1-

3} 

Complicati

on: 6 

(11.32%) 

SSI: 2 

(3.77%) 

SSO: 28 

(52.83%) 

Seroma/ 

hematoma

: 25 

(47.17%) 

Enterotom

y: 1 

(1.89%) 

Narc 

(mg/hr): 

POD0: 1.9 

{1.0-3.7}; 

POD1: 1.4 

{0.4-2.1}

Readmit: 5 

(4.8%) 

Reop: 2 

(1.94%)

LOS: 2 {2-

4} 

Complicati

on: 7 

(6.80%) 

SSI: 1 

(0.97%) 

SSO: 19 

(18.45%) 

Seroma/ 

hematoma

: 17 

(16.5%) 

Enterotom

y: 9 

(8.74%) 

Narc 

(mg/hr): 

POD0: 2.1 

{1.2-3.1}; 

POD1: 1.8 

{0.7-2.7}

F/U 

length: 

“short 

term” 

F/U 

length: 

“short 

term” 

Fascial defect more 

likely to be closed 

with robot (p<0.001) 

Longer operative 

time longer for robot 

(p<0.001) 

Shorter LOS with 

robot by 1 day 

(p=0.004) 

No difference in 

narcotic 

requirement 

through POD1 

(p=0.176) 

No difference in SSI 

(p=0.592), but 

increased SSO with 

robot (p<0.001), 

particularly seromas 

Similar periop 

complications

Cost

{}=IQR
Robot-assisted Procedures in General Surgery Evidence Synthesis Program

169

Size: 

82.5 

cm2

(69.8), 

width 

6.5 

(2.9) 

Recurr

ent: 

7.55%

width 

6.9 (4.1) 

Recurre

nt: 

1.94% 

Mortality: 0

Other: 3 

(5.66%) 

Ileus: 2 

(3.77%) 

Mortality: 1 

(0.97%) 

Other: 5 

(4.85%)

Ileus: 1 

(0.97%) 

Increased bowel 

injuries in lap group 

(p=0.011) 

Zayan, 

201976

Robot vs lap 

VHR 

Retrospectiv

e cohort 

Y 

N 

1/3 

N 

N=49 

N=16

Age: 

49.0 

(IQR 

42.2-

55.2) 

Male: 

62.5% 

BMI: 

48.97 

(IQR 

42.15-

55.23) 

ASA: 

NR 

DM: 

6.25% 

Tob: 

25.0% 

Electiv

e: 

100% 

Recurr

ent: 

12.5% 

CCS: 

8.8 

(IQR -

2.5-

15.7)

N=33

Age: 

51.5 

(IQR 

46.5-

56.2) 

Male: 

42.4% 

BMI: 

33.71 

(IQR 

30.84-

42.88) 

ASA: 

NR 

DM: 

15.2% 

Tob: 

9.1% 

Elective

: 100% 

Recurre

nt: 

12.1% 

CCS: 

23.9 

(IQR 

12.1-

34.1) 

OR time: 

139 (IQR 

108-186)

Mesh:

100%

Closure:

100%

Concurre

nt: 6.06%

BIHR

OR time: 

86 (IQR 

67-104)

Mesh:

100%

Closure:

87.9%

Concurre

nt: 0%

LOS (hrs): 

22.1 (IQR 

9.4-33.7) 

CCS: 19.0 

(IQR -8.3-

34.2) 

LOS (hrs): 

46.3 (IQR 

26.3-65.6) 

CCS: 24.3 

(IQR 3.8-

33.7)

F/U 

length: 

14.4 mo 

(IQR 

12.9-

15.8) 

Recur: 

0% 

QOL

(CCS): 

17.2 

(IQR 1.7-

31.5) 

F/U 

length: 

15.1 mo 

(IQR 13.9-

16.2) 

Recur: 1 

(3.0%) 

QOL 

(CCS): 6.8 

(IQR 2.1-

11.4) 

No difference in 

rate of fascial 

closure (p=0.289) 

Shorter LOS in 

robotic VHR 

(p=0.044) 

Shorter OR time for 

lap (p=0.009), 

although robot 

operative times 

decrease with 

number of cases 

and are comparable 

to lap 

No significant 

difference in QOL 

(CCS) outcomes 

between robot vs 

lap 

Cost
Robot-assisted Procedures in General Surgery Evidence Synthesis Program

170

APPENDIX H. CITATIONS FOR EXCLUDED PUBLICATIONS

Cholecystectomy

Comparison (n=4) 

1. Ayloo, S., Y. Roh and N. Choudhury (2014). "Laparoscopic versus robot-assisted

cholecystectomy: a retrospective cohort study." Int J Surg 12(10): 1077-1081.

2. Jeong, S. Y., J. W. Lee, S. H. Choi and S. W. Kwon (2018). "Single-incision laparoscopic

cholecystectomy using instrumental alignment in robotic single-site cholecystectomy."

Ann Surg Treat Res 94(6): 291-297.

3. Lim, C., G. Bou Nassif, E. Lahat, M. Hayek, M. Osseis, C. Gomez-Gavara, T.

Moussalem, D. Azoulay and C. Salloum (2017). "Single-incision robotic

cholecystectomy is associated with a high rate of trocar-site infection." Int J Med Robot

13(4).

4. Morel, P., F. Pugin, P. Bucher, N. C. Buchs and M. E. Hagen (2012). "Robotic singleincision laparoscopic cholecystectomy." J Robot Surg 6(3): 273-274.

No Outcome of Interest (n=4)

1. Aslam U, Amadi C, Goparaju A, Brathwaite CE, Adrales GL. Trends in Use of RoboticAssisted Surgery for Inpatient Elective General Surgery in the United States, 2010–2015.

Journal of the American College of Surgeons. 2019;229(4):S116.

2. Aslam U, Howell RS, Brathwaite CEM, Adrales G. Analysis of Outcomes for Elective

Inpatient Robotic-Assisted, Laparoscopic, and Open General Surgery in the United

States, 2010–2015. Journal of the American College of Surgeons. 2019;229(4):S88.

3. Norwick, P. M., S. Shaheen, J. Blebea, N. Conti, R. Heckburn, M. Zayout, J. Clements

and M. Ghanem (2019). "Robotic vs standard laparoscopic cholecystectomy: Clinical

outcomes." Surgical Endoscopy 33: S397.

4. Sheetz KH, Claflin J, Dimick JB. Trends in the Adoption of Robotic Surgery for

Common Surgical Procedures. JAMA Network Open. 2020;3(1).

No Clinical Data (n=3)

1. Armijo, P. R., S. Pagkratis, E. Boilesen, T. Tanner and D. Oleynikov (2018). "Growth in

robotic-assisted procedures is from conversion of laparoscopic procedures and not from

open surgeons' conversion: a study of trends and costs." Surg Endosc 32(4): 2106-2113.

2. Coca-Soliz, VS, R. C. Gooding, J. Hubbard and P. R. Corvo (2017). "Comparison of

laparoscope versus da vinci robot on surgical site infections based on operation time and

operator volume." Surgical Endoscopy and Other Interventional Techniques 31: S314.

3. Hirides, S. (2017). "Cholecystectomy using conventional lap, minilap needlescopic or

robotic single-site approaches. A technical comparison." Surgical Endoscopy and Other

Interventional Techniques 31(2): S235.
Evidence Synthesis Program

171

Robot-assisted Procedures in General Surgery

Other (n=2)

1. Aziz, H., M. Zeeshan, R. R. Selby and M. R. Sheikh (2019). "Looking beyond

laparoscopic cholecystectomy – Will robotic cholecystectomy be the new the gold

standard in patients with advanced liver disease?" HPB 21: S31.

2. Lee, M. M., K. K. Seeras and J. J. Lim (2019). "Cost comparison of single site robotic

and conventional laparoscopic cholecystectomy at a single institution." Surgical

Endoscopy 33: S395.

Review/Editorial (n=8)

1. Awad, M. M. and J. W. Fleshman (2010). "Robot-assisted surgery and health care costs

[10]." New England Journal of Medicine 363(22): 2174-2175.

2. Barbash, G. I. and S. A. Glied (2010). "New technology and health care costs - The case

of robot-assisted surgery." New England Journal of Medicine 363(8): 701-704.

3. Biglarian, S. and N. Katkhouda (2017). "Requesting Patient Characteristics for

Readmissions Noted in "Single-site Robotic Cholecystectomy in a Broadly Inclusive

Patient Population: A Prospective Study"." Ann Surg 265(4): e34-e35.

4. Brody, F. and N. G. Richards (2014). "Review of robotic versus conventional

laparoscopic surgery." Surgical Endoscopy 28(5): 1413-1424.

5. Castellanos, A., J. Fazendin and L. Panait (2015). "Single-incision laparoscopic

cholecystectomy." Clinical Liver Disease 5(1): 5-7.

6. Giulianotti, P. C. (2017). "Why I think the robot will be the future for laparoscopic

cholecystectomies." Surgery 161(3): 637-638.

7. Lee, E. K., E. Park, W. O. Oh and N. M. Shin (2017). "CORRIGENDUM: Correction of

the affiliation name. Comparison of the outcomes of robotic cholecystectomy and

laparoscopic cholecystectomy." Ann Surg Treat Res 93(4): 229.

8. Newman, R. M., A. Umer and S. Ellner (2016). "Traditional Four-Port vs Single-Incision

and Robotically Assisted Cholecystectomy: In reply to Bloomstone and colleagues." J

Am Coll Surg 223(1): 208.

Duplicate (n=11) 

1. Armijo, P. R., S. Pagkratis, E. Boilesen, T. N. Tanner and D. Oleynikov (2017). "Growth

in robotic-assisted procedures is from conversion of laparoscopic procedures and not

from open surgeons conversion: a study of trends and costs." Surgical endoscopy and

other interventional techniques. Conference: 2017 scientific session of the society of

american gastrointestinal and endoscopic surgeons, SAGES 2017. United States 31: S31.

2. Balachandran, B., T. Mustafa, T. A. Hufford, K. Kochar, L. M. Prasad, S. Sulo and J.

Khorsand (2016). "A comparative study of outcomes between single-site robotic and

multi-port laparoscopic cholecystectomy: An experience from a tertiary care center."

Surgical Endoscopy and Other Interventional Techniques 30: S258.

3. Charles EJ, Hunter Mehaffey J, Kane WJ, Hawkins RB, Tache-Leon CA, Yang Z.

Robotic compared to laparoscopic cholecystectomy: A propensity matched analysis.

Surgical Endoscopy and Other Interventional Techniques. 2018;32(1):S34.

4. Gonzalez AM, Verdeja JC, Rabaza JR, et al. Single incision cholecystectomy:

Comparative study between laparoscopic, robotic and spider platforms. Surgical
Robot-assisted Procedures in General Surgery Evidence Synthesis Program

172

Endoscopy and Other Interventional Techniques. 2013;27:S274. 

5. Grochola, L. F., C. Soll and S. Breitenstein (2018). "Robot-assisted single-site compared

with laparoscopic single-incision cholecystectomy for benign gallbladder disease: results

of a single-blinded randomized controlled trial." European surgical research. Europaische

chirurgische forschung. Recherches chirurgicales europeennes 59: 4‐.

6. Grochola, L. F., C. Soll, A. Zehnder, R. Wyss, P. Herzog and S. Breitenstein (2018).

"Robot-assisted versus laparoscopic single-incision cholecystectomy: results of a

randomized controlled trial." Surgical endoscopy.

7. Grochola, L. F., C. Soll, A. Zehnder, R. Wyss, P. Herzog and S. Breitenstein (2018).

"Robot-assisted single-site compared with laparoscopic single-incision cholecystectomy

for benign gallbladder disease: results of a single-blinded randomized controlled trial."

HPB 20: S726.

8. Grochola, L. F., C. Soll, A. Zehnder, R. Wyss, P. Herzog and S. Breitenstein (2018).

"Robot-Assisted Single-Site compared with laparoscopic single-incision cholecystectomy

for benign gallbladder disease: Results of a single-blinded randomized controlled trial."

Swiss Medical Weekly 148: 4S.

9. Higgins, R. M., M. J. Frelich, M. E. Bosler and J. C. Gould (2016). "Cost analysis of

robotic versus laparoscopic general surgery procedures." Surgical Endoscopy and Other

Interventional Techniques 30: S243.

10. Kaminski, J. P., K. W. Bueltmann and M. Rudnicki (2014). "Robotic versus laparoscopic

cholecystectomy: Does the end justify the means?" Surgical Endoscopy and Other

Interventional Techniques 28: 262.

11. Newman, R. M., B. J. Bozzuto, J. L. Dilungo and S. J. Ellner (2014). "The surgical value

of nontraditional, minimally invasive gallbladder removal: Traditional 4 port vs single

incision and robotically-assisted cholecystectomy." Journal of the American College of

Surgeons 219(4): e34.

Inguinal Hernia Repair 

Comparison (n=2) 

1. Edelman, D. (2018). "Is robotic inguinal hernia repair safe?" Hernia 22(1): S103.

2. Edelman, D. S. (2017). "Robotic inguinal hernia repair." Surgical Endoscopy and Other

Interventional Techniques 31: S330.

No Clinical Data (n=3)

1. Delgado, M., J. C. Quispe, K. Medani, C. Wang and E. Yung (2019). "A 5 year

retrospective study comparing results of laparoscopic versus robotic inguinal hernia

repair." Journal of Investigative Medicine 67(1): 221.

2. McCoy, K., W. Symons, J. Clarke, M. Novack and M. Broderick (2018). "Open versus

robotic inguinal hernia repair: Is there a superior approach?" Surgical Endoscopy and

Other Interventional Techniques 32(1): S346.

3. Verduzco-Gomez, E., A. Badami and F. Sabido (2018). "Robotic inguinal hernia repair

eliminates the need for post-operative narcotics and demonstrates lower post-operative

pain scores." Hernia 22(1): S183.
Evidence Synthesis Program

173

Robot-assisted Procedures in General Surgery

No Outcome of Interest (n=6)

1. Armijo, P. R., S. Pagkratis, E. Boilesen, T. N. Tanner and D. Oleynikov (2017). "Growth

in robotic-assisted procedures is from conversion of laparoscopic procedures and not

from open surgeons conversion: a study of trends and costs." Surgical endoscopy and

other interventional techniques. Conference: 2017 scientific session of the society of

american gastrointestinal and endoscopic surgeons, SAGES 2017. United States 31: S31.

2. Aslam U, Amadi C, Goparaju A, Brathwaite CE, Adrales GL. Trends in Use of RoboticAssisted Surgery for Inpatient Elective General Surgery in the United States, 2010–2015.

Journal of the American College of Surgeons. 2019;229(4):S116.

3. Aslam U, Howell RS, Brathwaite CEM, Adrales G. Analysis of Outcomes for Elective

Inpatient Robotic-Assisted, Laparoscopic, and Open General Surgery in the United

States, 2010–2015. Journal of the American College of Surgeons. 2019;229(4):S88.

4. Muysoms, F., C. Ballecer and A. Ramaswamy (2018). "Evaluation of the operative time

for robotic assisted laparoscopic groin hernia repair during the learning curve of 125

cases." Surgical Endoscopy and Other Interventional Techniques 32(1): S144.

5. Sheetz KH, Claflin J, Dimick JB. Trends in the Adoption of Robotic Surgery for

Common Surgical Procedures. JAMA Network Open. 2020;3(1).

6. Zayadin Y, D'John J, Yaldo B, McKany M. Urinary Retention Post Open vs

Laparoscopic vs Robotic Inguinal Hernia Repair: A Comparative Retrospective Review.

Journal of the American College of Surgeons. 2019;229(4):e129.

Procedure (n=1)

1. Tran, H. (2011). "Robotic single-port hernia surgery." Jsls 15(3): 309-314.

Systematic Review (n=1)

1. Jacks BE, Agor UJ, Sanni AO. Clinical Outcomes after Robotic Assisted Transabdominal

Preperitoneal (R-TAPP) vs Laparoscopic Totally Extraperitoneal (L-TEP) Inguinal

Hernia Repair. Journal of the American College of Surgeons. 2019;229(4):e109.

Review/Editorial (n=2)

1. Bernhardt, G. A., K. Gruber and G. Gruber (2010). "TAPP repair in a giant bilateral

scrotal hernia - limits of a method." ANZ J Surg 80(12): 947-948.

2. Godshall, E., S. Eckhouse, C. Johnson, A. Patterson and R. Pullatt (2015).

"Transabdominal Preperitoneal Inguinal Hernia Repair as a Salvage Operation after

Failure of Prior Total Extraperitoneal Repair." Am Surg 81(8): 312-313.

Duplicate (n=3)

1. Hennings, D. L., P. R. Armijo and D. Oleynikov (2018). "Robotic inguinal hernia repair

is superior to open or laparoscopic inguinal hernia repair: A national data base review."

Surgical Endoscopy and Other Interventional Techniques 32(1): S344.

2. Muysoms, F., C. Ballacer, A. Ramaswamy, S. Van Cleven and I. Kyle-Leinhase (2017).

"Evaluation of the operative time for robotic assisted laparoscopic groin hernia repair
Robot-assisted Procedures in General Surgery Evidence Synthesis Program

174

during the learning curve." Hernia 21(2): S159. 

3. Zayan NE, Meara MP, Schwartz JS, Narula VK. A direct comparison of robotic and

laparoscopic hernia repair: patient-reported outcomes and cost analysis. Hernia.

2019;23(6):1115-1121.

Unavailable (n=1)

1. Edelman, D. S. (2017). "Robotic Inguinal Hernia Repair." Am Surg 83(12): 1418-1421.

Ventral Hernia Repair 

Comparison (n=6) 

1. Halka, J., A. Vasyluk, A. DeMare, A. Iacco and R. Janczyk (2018). "Hybrid robotic

assisted transversus abdominis release is associated with a significantly decreased length

of stay without increased complications compared to open transversus abdominis release

in patients with large ventral hernias." Hernia 22(1): S27.

2. Halka, J. T., A. Vasyluk, A. Demare, A. Iacco and R. Janczyk (2019). "Hybrid roboticassisted transversus abdominis release versus open transversus abdominis release: a

comparison of short-term outcomes." Hernia 23(1): 37-42.

3. Muse, T. O., B. A. Zwischenberger, M. T. Miller, D. A. Borman, D. L. Davenport and J.

S. Roth (2018). "Outcomes after Ventral Hernia Repair Using the Rives-Stoppa,

Endoscopic, and Open Component Separation Techniques." Am Surg 84(3): 433-437.

4. Oviedo, R. J., J. C. Robertson and A. S. Desai (2017). "Robotic Ventral Hernia Repair

and Endoscopic Component Separation: Outcomes." Jsls 21(3).

5. Sailes, F. C., J. Walls, D. Guelig, M. Mirzabeigi, W. D. Long, A. Crawford, J. H. Moore,

Jr., S. E. Copit, G. A. Tuma and J. Fox (2011). "Ventral hernia repairs: 10-year singleinstitution review at Thomas Jefferson University Hospital." J Am Coll Surg 212(1): 119-

123.

6. Ioannidis A, Machairas N, Koutserimpas C, Spartalis E, Konstantinidis M, Konstantinidis

K. Evolution of robot-assisted general surgery in Greece and Cyprus. Journal of Robotic

Surgery. 2019;13(2):315-317.

No Outcome of Interest (n=7) 

1. Addo AJ, Zahiri HR, Broda A, et al. Early Perioperative Outcomes in Obese Patients

Undergoing Minimally Invasive Abdominal Wall Reconstruction. Journal of the

American College of Surgeons. 2019;229(4):e112.

2. Armijo PR, Pagkratis S, Boilesen E, Tanner T, Oleynikov D. Growth in robotic-assisted

procedures is from conversion of laparoscopic procedures and not from open surgeons’

conversion: a study of trends and costs. Surgical Endoscopy. 2018;32(4):2106-2113.

3. Aslam U, Amadi C, Goparaju A, Brathwaite CE, Adrales GL. Trends in Use of RoboticAssisted Surgery for Inpatient Elective General Surgery in the United States, 2010–2015.

Journal of the American College of Surgeons. 2019;229(4):S116.

4. Aslam U, Howell RS, Brathwaite CEM, Adrales G. Analysis of Outcomes for Elective

Inpatient Robotic-Assisted, Laparoscopic, and Open General Surgery in the United
Robot-assisted Procedures in General Surgery Evidence Synthesis Program

175

States, 2010–2015. Journal of the American College of Surgeons. 2019;229(4):S88. 

5. Forester B, Donovan K, Kuchta K, et al. Short-Term Quality of Life Comparison of

Laparoscopic, Open, and Robotic Incisional Hernia Repairs. Journal of the American

College of Surgeons. 2019;229(4):e127.

6. Sheetz KH, Claflin J, Dimick JB. Trends in the Adoption of Robotic Surgery for

Common Surgical Procedures. JAMA Network Open. 2020;3(1).

7. Zayan NE, Meara MP, Schwartz JS, Narula VK. A direct comparison of robotic and

laparoscopic hernia repair: patient-reported outcomes and cost analysis. Hernia.

2019;23(6):1115-1121.

Sample Size (n<10) (n=2) 

1. Belyansky, I., A. S. Weltz, U. S. Sibia, J. J. Turcotte, H. Taylor, H. R. Zahiri, T. R.

Turner and A. Park (2018). "The trend toward minimally invasive complex abdominal

wall reconstruction: is it worth it?" Surgical Endoscopy 32(4): 1701-1707.

2. Mejia, A., C. G. Fasola and A. Stegall (2019). "Incisional ventral hernia repair (IVHR) in

post liver transplant recipients (OLT) through a robotic-assisted intervention (RAI):

Initial single-center experience." American Journal of Transplantation 19: 863-864.

Case series n<10 (n=2)

1. Daes, J. (2014). "Endoscopic subcutaneous approach to component separation." J Am

Coll Surg 218(1): e1-4.

2. Gillespie, J. W., 3rd, D. D. Zabel, M. K. Conway, E. D. Kalish and D. E. Sarmiento

Garzon (2015). "Abdominal Wall Reconstruction for Large Ventral Hernias in the

Octogenarian." Am Surg 81(11): E373-375.

Systematic Review (n=1)

1. Souza, J. M. and G. A. Dumanian (2012). "An evidence-based approach to abdominal

wall reconstruction." Plast Reconstr Surg 130(1): 116-124.

Review (n=1) 

1. (2012). "Hernia repair: which surgical approach is best?" Johns Hopkins Med Lett Health

After 50 24(8): 4-5.

Duplicate (n=6) 

1. Addo A, Parlacoski S, Ewart Z, Broda A, Zahiri R, Belyansky I. Comparative review of

outcomes: Laparoscopic and robotic enhanced-view totally extraperitoneal rives-stoppa

abdominal wall reconstruction. Surgical Endoscopy. 2019;33:S15.Alrefai, S., M. Mabe,

M. Vy, P. Del Prado, N. L. Clingempeel and J. G. Bittner (2017). "Comparative analysis

of robot-assisted minimally invasive vs open transvs abdomens release outcomes in

abdominal wall reconstruction." Journal of the American College of Surgeons 225(4):

e83-e84.

2. Alrefai S, Mabe M, Vy M, Del Prado P, Clingempeel NL, Bittner JG. Comparative
Robot-assisted Procedures in General Surgery Evidence Synthesis Program

176

analysis of robot-assisted minimally invasive vs open transvs abdomens release outcomes 

in abdominal wall reconstruction. Journal of the American College of Surgeons. 

2017;225(4):e83-e84. 

3. Costa, T. N., R. Z. Abdalla, I. Cecconello and U. Ribeiro (2017). "Randomized clinical

trial: Comparison between robotic assisted and laparoscopic incisional hernia repair."

Hernia 21(2): S158.

4. Khorgami, Z., T. Jackson, W. T. Li, C. A. Howard and G. M. Sclabas (2017). "Extra

costs of robotic surgery in minor and major surgeries: An analysis of national inpatient

sample." Journal of the American College of Surgeons 225(4): e86.

5. Walker, P., A. May, M. R. Santillan, S. Kim, S. Shah, E. Wilson, M. Liang and S. Tsuda

(2017). "Multicenter review of robotic versus laparoscopic ventral hernia repair: is there a

role for robotics?" Surgical endoscopy and other interventional techniques. Conference:

2017 scientific session of the society of american gastrointestinal and endoscopic

surgeons, SAGES 2017. United states 31: S29.

6. Weltz, A. S., J. Turcotte, U. S. Sibia, E. Zakharov, N. Wu, T. R. Turner, A. Park, H. R.

Zahiri and I. Belyansky (2017). "The trend toward minimally invasive complex

abdominal wall reconstruction: Is it worth it?" Surgical Endoscopy and Other

Interventional Techniques 31: S22.

Unavailable (n=1)

1. Espinosa-de-los-Monteros, A. (2012). "[Abdominal wall reconstruction for complex

incisional hernias]." Rev Invest Clin 64(6 Pt 2): 634-640.