in recent years there has been a shift toward minimally invasive surgical techniques . included in this shift has been the widespread adoption of laparoscopy as an alternative to the open operative approach in colon and rectal surgery . with the advancement of laparoscopic techniques compared with open surgery , laparoscopy has been shown to reduce intraoperative blood loss , length of incision , and length of hospital stay . as was seen with the movement from purely open surgery to laparoscopy , we are now witnessing a rising popularity and acceptance of robot - assisted procedures in a variety of surgical fields . the approval and increasing use of robotic equipment among surgeons stem somewhat from the technologic advancements that robotic surgery provides over traditional laparoscopic surgery . robotic surgery has been observed to be advantageous in its 3-dimensionally represented operating field , eliminating difficulties associated with depth perception as are seen with standard laparoscopy 's 2-dimensional image . in addition , a surgeon - operated camera allows for full control of the visual operating field , whereas the endowrist function ( intuitive surgical , sunnyvale , california ) provides increased articulation and rotation in a confined space . much of the controversy surrounding the robot pertains to the high cost and longer operative time associated with robotic procedures . the learning curve associated with new technology , as well as the increased time involved in docking ( and redocking in some cases ) , contributes to the overall operative time and , consequently , the cost of the procedure compared with traditional laparoscopy . in a study by park et al , a robotic right colectomy cost the patient > $ 3600 more out of pocket than a laparoscopic right colectomy . although some of the technical limitations of standard laparoscopy may obviously be addressed with the robotic apparatus , whether these advantages are enough to offset the higher cost of the robot are still debatable . furthermore , few studies have conclusively shown whether robot - assisted procedures yield different outcomes . specifically , studies conducted primarily in asia and europe have been published , but there still remains a paucity of studies in the united states comparing outcomes such as length of hospital stay , estimated blood loss , duration of the procedure , and complications between a robotic approach and laparoscopy for colon and rectal operations . the lack of comparative studies between robotic and laparoscopic approaches regarding specific outcomes , combined with the cost of new technology like the da vinci robot ( intuitive surgical ) , is a prohibitive factor for widespread adoption of the robot in many hospital centers . this study aims to compare and contrast our experience with robot - assisted and laparoscopic approaches to colon and rectal procedures to elucidate any differences in outcomes . we performed a retrospective review of 40 patients who underwent either standard laparoscopic or robotic colorectal surgery with the da vinci si robot ( intuitive surgical ) at tulane medical center , new orleans , louisiana , between january 2008 and february 2013 . patients were randomly assigned to undergo either a standard laparoscopic or robotic procedure based on the availability of the robot apparatus . indications for surgery were documented but did not factor into the inclusion or exclusion criteria for the study . the primary data points included operation time , estimated blood loss , length of stay , complications , and whether the procedure was converted to open . there was no standard protocol in place for advancement of the patients ' diet postoperatively . when malignancy was the indication for surgery , additional data points including histologic diagnosis , clinical stage , and number of nodes collected were noted . cases were performed by 1 of 2 authors ( or both ) . the student t test and test ( as well as the fisher exact test where appropriate ) were used to examine the association between each of the independent factors and outcomes for continuous and categorical variables , respectively . given the small sample size and varied procedure types , 2 subanalyses were performed for the aforementioned intraoperative and postoperative outcomes , one excluding procedures with concomitant liver resection and one solely for right hemicolectomy . all statistical analyses were performed by use of spss software ( version 19 ; ibm , armonk , new york ) . all procedures were performed by a single surgeon who had prior experience with the da vinci si robot in liver , spleen , pancreas , stomach , thyroid , and gallbladder procedures . in this series the surgical steps did not differ between the robotic and laparoscopic approaches , as has been described in previously published studies . the differences in port placement between the laparoscopic and robot - assisted procedures are to accommodate the robotic arms , in addition to an extra port(s ) for the surgeon 's assistant . port placement was standard for the type of procedure and for the approach ( laparoscopic vs robot assisted ) , as has been described previously . we performed a retrospective review of 40 patients who underwent either standard laparoscopic or robotic colorectal surgery with the da vinci si robot ( intuitive surgical ) at tulane medical center , new orleans , louisiana , between january 2008 and february 2013 . patients were randomly assigned to undergo either a standard laparoscopic or robotic procedure based on the availability of the robot apparatus . indications for surgery were documented but did not factor into the inclusion or exclusion criteria for the study . the primary data points included operation time , estimated blood loss , length of stay , complications , and whether the procedure was converted to open . there was no standard protocol in place for advancement of the patients ' diet postoperatively . when malignancy was the indication for surgery , additional data points including histologic diagnosis , clinical stage , and number of nodes collected were noted . cases were performed by 1 of 2 authors ( or both ) . the student t test and test ( as well as the fisher exact test where appropriate ) were used to examine the association between each of the independent factors and outcomes for continuous and categorical variables , respectively . given the small sample size and varied procedure types , 2 subanalyses were performed for the aforementioned intraoperative and postoperative outcomes , one excluding procedures with concomitant liver resection and one solely for right hemicolectomy . all statistical analyses were performed by use of spss software ( version 19 ; ibm , armonk , new york ) . all procedures were performed by a single surgeon who had prior experience with the da vinci si robot in liver , spleen , pancreas , stomach , thyroid , and gallbladder procedures . in this series the surgical steps did not differ between the robotic and laparoscopic approaches , as has been described in previously published studies . the differences in port placement between the laparoscopic and robot - assisted procedures are to accommodate the robotic arms , in addition to an extra port(s ) for the surgeon 's assistant . port placement was standard for the type of procedure and for the approach ( laparoscopic vs robot assisted ) , as has been described previously . sixty - five percent of the patients were male patients with a mean body mass index ( bmi ) of 28.0  5.8 , and 37.5% had a history of abdominal surgery . of the study population , 37.5% had a complication related to the operation . in terms of operative technique there were no significant differences between the groups in terms of age , bmi , or history of abdominal surgery . the mean age of patients undergoing laparoscopic surgery versus robotic surgery was 61.1  10.7 years versus 61.1  8.5 years ( p = .997 ) , the mean bmi was 28.9  6.3 versus 26.2  4.2 ( p = .158 ) , and the percentage with a history of abdominal surgery was 44.0% versus 26.7% ( p = .273 ) . there was a significant difference in terms of sex , with more patients being male and undergoing robotic surgery ( 86.7% vs 52.0% , p = .026 ) . there was no significant difference in surgical indication between the 2 groups ( p = .303 ) . eighteen patients underwent right hemicolectomy , 1 underwent a sigmoidectomy , 3 underwent abdominoperineal resection ( apr ) , and 3 underwent low anterior resection ( lar ) performed laparoscopically . in addition , 4 patients in the laparoscopy group underwent concomitant liver resection for metastases . in the robotic group , 7 patients underwent a right hemicolectomy , 2 underwent a left hemicolectomy , 1 underwent apr , and 5 underwent lar . patient characteristics of laparoscopic and robotic groups data are presented as mean ( standard deviation ) unless otherwise indicated . operative time was similar between the laparoscopic and robotic groups ( 190.8  84.3 minutes vs 258.4  170.8 minutes , p = .183 ) , with similar estimated blood loss ( 163.3  249.2 ml vs 96.8  157.7 ml , p = .385 ) . in the laparoscopic group , 16.0% of cases were converted to open compared with 20.0% in the robotic group ( p > .99 ) . the mean time until postoperative passage of stool was 4.6  1.9 days in the laparoscopic group versus 4.2  0.83 days in the robotic group ( p = .427 ) ; the mean time until the initiation of a regular diet ( 4.5  1.5 days vs 5.8  3.2 days , p = .159 ) was not significantly different between the 2 groups . furthermore , the mean length of stay after laparoscopic surgery was 9.6  7.3 days and was not different from the mean length of stay after robotic surgery ( 6.5  3.8 days , p = .091 ) . the rate of complications was similar for patients undergoing the laparoscopic approach versus those undergoing the robotic approach ( 36.0% vs 20.0% , p = .457 ) ( table 2 ) . of note , 1 patient undergoing the robotic procedure had an intraoperative splenic injury , which was repaired with splenorrhaphy . in addition , 1 patient  a 67-year - old woman undergoing a robot - assisted apr intraoperative and postoperative outcomes data are presented as mean ( standard deviation ) unless otherwise indicated . the oncologic characteristics of the colorectal operations performed for cancer resection were also noted ( table 3 ) . there was no significant difference in tumor stage ( p = .4882 ) or histologic grade ( p > .99 ) between the 2 groups . in addition , there was no significant difference in the number of lymph nodes harvested between the laparoscopic group ( 14.0  6.5 ) and the robotic group ( 12.3  4.2 , p = .683 ) . pathologic characteristics for colorectal cancer operations the subanalysis for outcomes of procedures excluding concomitant liver resections is shown in table 4 . no liver resections were performed robotically ; thus the data in the subanalysis only varied in the laparoscopic arm . the duration of laparoscopic procedures averaged 175.2  67.6 minutes versus 258.4  170.8 minutes for robotic procedures ( p = .183 ) . furthermore , blood loss in the laparoscopic group ( 69.7  74.2 ml ) was not different from that in the robotic group ( 96.8  157.7 ml , p = .544 ) . for all other parameters  rate of conversion to laparotomy , time to passage of stool , time until resumption of a regular diet , length of stay , and complications  there remained no statistically significant differences or any large changes to the raw data . intraoperative and postoperative outcomes for operations excluding concomitant liver resection data are presented as mean ( standard deviation ) unless otherwise indicated . the mean operative time was 146.9  50.0 minutes in the laparoscopic group compared with 145.4  39.9 minutes in the robotic group ( p = .945 ) . mean blood loss was likewise not statistically different between the laparoscopic group ( 78.1  79.6 ml ) and robotic group ( 43.6  29.8 ml , p = .288 ) . the times to passage of stool were similar between the laparoscopic group ( 4.1  1.7 days ) and the robotic group ( 4.0  0.6 days ) , and the finding was not significant ( p = .902 ) . the remaining outcomes examined , including conversion to laparotomy , length of stay , and complications , continued to be similar to the aggregate analysis and were not statistically significant . intraoperative and postoperative outcomes for right hemicolectomy data are presented as mean ( standard deviation ) unless otherwise indicated . the subanalysis for outcomes of procedures excluding concomitant liver resections is shown in table 4 . no liver resections were performed robotically ; thus the data in the subanalysis only varied in the laparoscopic arm . the duration of laparoscopic procedures averaged 175.2  67.6 minutes versus 258.4  170.8 minutes for robotic procedures ( p = .183 ) . furthermore , blood loss in the laparoscopic group ( 69.7  74.2 ml ) was not different from that in the robotic group ( 96.8  157.7 ml , p = .544 ) . for all other parameters  rate of conversion to laparotomy , time to passage of stool , time until resumption of a regular diet , length of stay , and complications  there remained no statistically significant differences or any large changes to the raw data . intraoperative and postoperative outcomes for operations excluding concomitant liver resection data are presented as mean ( standard deviation ) unless otherwise indicated . the mean operative time was 146.9  50.0 minutes in the laparoscopic group compared with 145.4  39.9 minutes in the robotic group ( p = .945 ) . mean blood loss was likewise not statistically different between the laparoscopic group ( 78.1  79.6 ml ) and robotic group ( 43.6  29.8 ml , p = .288 ) . the times to passage of stool were similar between the laparoscopic group ( 4.1  1.7 days ) and the robotic group ( 4.0  0.6 days ) , and the finding was not significant ( p = .902 ) . the remaining outcomes examined , including conversion to laparotomy , length of stay , and complications , continued to be similar to the aggregate analysis and were not statistically significant . intraoperative and postoperative outcomes for right hemicolectomy data are presented as mean ( standard deviation ) unless otherwise indicated . interest in use of the robot in colorectal procedures has increased in recent years . for any new operative technique to become an accepted alternative to traditional methods for instance , studies have emerged since the adoption of laparoscopy for colorectal operations that have shown that it can yield a decreased length of hospital stay , oncologically adequate resection , and no differences in postoperative complications or in - hospital deaths when compared with a traditional open approach . because of studies like these , laparoscopy is now considered an acceptable alternative to an open approach in colorectal resection . our current experience shows many of the similarities between patients undergoing laparoscopic colorectal surgery and those undergoing robotic - assisted colorectal surgery and suggests that robot - assisted colon and rectal surgery is a safe and feasible alternative to the conventional laparoscopic approach . this study was conducted in groups of patients that were similar in terms of demographic characteristics and indications for operation . there was no significant difference between the robotic and laparoscopic groups in terms of age , bmi , or history of abdominal surgery . regarding operative outcomes , no significant difference was noted between the 2 groups in terms of complication rate , estimated blood loss , conversion to open procedure , or length of hospital stay . return of bowel function and resumption of a regular diet were also noted to be similar between the 2 groups . across all operations and approaches , the number and location of ports did not appear to have a clinically observable effect on intraoperative and postoperative outcomes including the need to convert to laparotomy , complications , and length of hospital stay . consequently , this study of well - matched patients establishes the equivalence in outcomes that can be achieved between laparoscopic and robotic approaches to colon and rectal surgery . the 2 subanalyses sought to create better - matched patient groups and decrease the large standard deviations as a result of aggregating a broad range of procedures . two ways of accomplishing this were to ( 1 ) eliminate procedures with concomitant liver resection and ( 2 ) include only right colectomies , the most commonly performed procedure in our study . in the subanalysis of outcomes , excluding cases with concomitant liver resection yielded a large drop in estimated blood loss , as well as duration of the procedure . however , there continued to be no statistically significant difference in any of the outcomes . likewise , although the subanalysis of right colectomies showed nearly identical operative times , greatly decreased blood loss ( laparoscopy - associated blood loss again greater than robotic ) , and smaller standard deviations , none of the differences were significant . thus , despite attempting to better match the patient groups , the results remained similar between the laparoscopic and robotic procedures . our results are similar to those shown in the randomized clinical trial by park et al that compared outcomes of robot - assisted and laparoscopic approaches for right - sided colon cancer . they showed no difference in complications , blood loss , conversion to open surgery , time to passage of flatus , or time to resume a regular diet between the 2 groups . other studies , by rawlings et al and d'annibale et al , have also shown similar findings . in the study by rawlings et al , when examining right colectomy operations , no difference was seen between the laparoscopic and robot - assisted groups in terms of length of hospital stay and estimated blood loss . at present , the literature shows conflicting results in terms of the duration of the operation between the 2 surgical techniques . similar to our findings , d'annibale et al noted no significant variation in operative times between the robotic and laparoscopic groups . in contrast , park et al found that the duration of the operation was significantly shorter in the laparoscopic group compared with the robot - assisted group ( 130 minutes vs 195 minutes , p < .001 ) . likewise , rawlings et al noted a significant difference in operative time ( mean of 169 minutes in laparoscopic group vs 219 minutes in robotic group , p = .002 ) . further well - matched studies are needed to truly elucidate whether there is a significant difference in operative times between the 2 surgical approaches . whether patients had a history of abdominal surgery the fact that patients in both study arms had similar histories of abdominal operations suggests that prior abdominal surgery is not a contraindication to robotic - assisted surgery . in addition , the rate of conversion to an open procedure was not significantly different between the laparoscopic and robot - assisted groups . this finding is comparable with results reported in studies by park et al and trastulli et al , both of which examined patients undergoing robotic right colon resections . in the comparative study by park et al , there was no difference in the number of cases converted to an open procedure : none of the 35 robot - assisted cases were converted to open surgery ; nor were any of the 35 laparoscopic cases . likewise , in the study by trastulli et al examining a consecutive series of 20 patients , none were converted to open surgery . in our study , none of the robotic right colon resections were converted to an open procedure , whereas in the laparoscopic group , only 1 patient , who also underwent concomitant liver resection , was converted to open surgery . in contrast to the aforementioned results , a study of rectal cancer resections in 84 patients ( laparoscopic in 37 and robot assisted in 47 ) by baek et al found a significantly higher rate of conversion to open surgery in the laparoscopic group compared with the robotic group ( p = .020 ) . together , these findings indicate that conversion to an open procedure likely occurs at similar rates between the 2 approaches and that there may in fact be superior outcomes after a robotic approach for colon and rectal surgery . when operations are performed for cancer resection , new techniques must not only be safe but also provide a comparable outcome for oncologic resection . in this study we performed a subanalysis comparing laparoscopic versus robotic surgery that examined oncologic outcome . there was no difference in the number of lymph nodes harvested in cases performed as a result of colorectal malignancy , and both approaches yielded an average number of lymph nodes > 12 , proving the techniques oncologically sufficient . similarly , studies by d'annibale et al and park et al reported no difference between the approaches in harvesting nodes . in these studies , robot - assisted resection obtained , on average , 17 nodes and 29.9 nodes , respectively the series of 20 patients undergoing robotic right colectomy reported by trastulli et al also showed oncologic sufficiency by harvesting an average of 17.6 lymph nodes . although the technical limitations of standard laparoscopy are addressed with the robotic apparatus by using a 3-dimensional field and improved instrument articulation and rotation , there remain certain disadvantages to consider . because robot - assisted operations are still relatively new , the process to set up and dock robotic arms increases the length of time in the operating room . even with an experienced team , the prolonged time is a drawback compared with conventional laparoscopy . perhaps more important than operating room time , however , is the duration of the procedure because it is of greatest importance to the patient that prolonged risks of anesthesia are mitigated . it has been shown that colorectal surgery is associated with cardiac complications that are exacerbated by longer operative times and are associated with mortality rates of 20% to 40% . the single patient death in this study , as a result of cardiac arrest , occurred in a 67-year - old woman undergoing a particularly complicated robotic apr for squamous cell carcinoma of the anal canal that lasted 492 minutes . as was seen in this study , however , as well as other studies of right colectomies , the duration of the operation overall was not significantly different between the laparoscopic group and the robotic group . when the robotic operative time is averaged after excluding this apr case , the time is 240.5  160.3 minutes , a nonsignificant difference from the laparoscopic time . this time is similar to average operative times for robotic colorectal procedures published in the current literature . although some surgeons may question , on the basis of this instance of death after a robotic apr , the safety of the robot as a surgical modality , studies have shown low mortality rates . a systematic review by kanji et al of robot - assisted colorectal procedures encompassing 854 patients yielded no reported deaths . similarly , salman et al , in an assessment of the nationwide inpatient sample , found a mortality rate of 79.1 per 10 000 laparoscopic colorectal procedures compared with a rate of 0.0 per 10 000 robotic cases ( p < .05 ) . thus , despite the single case of death in our study , both laparoscopic colorectal surgery and robotic colorectal surgery have been shown to have low in - hospital mortality rates . multiple studies have shown that robot - assisted surgery is significantly more costly than standard laparoscopic surgery . we did not analyze cost in our study , but prior publications showed a greater expense of thousands of dollars when using the robotic approach compared with traditional laparoscopy . in addition to cost being a limitation to the robotic approach in hospitals , robotic surgery also results in a greater out - of - pocket expense for patients . although many studies , including our study , have shown that in most aspects , outcomes are similar between both modalities , significant advantages and benefits to the robotic approach over the laparoscopic approach may be necessary to justify the use of the robot in some centers . in other centers , however , the standardization of robotics in surgery may lead to cost savings over time . the small sample size and retrospective nature of our study present some inherent limitations . at our institution , the robotic approach to colorectal surgery has not become widely adopted , and as such , there are fewer of these procedures being performed . however , this study and its exploratory nature serve as preliminary evidence in the comparison of laparoscopic and robotic colorectal surgery through an appropriate design . at the same time , this study establishes a basis for larger - scale investigation with wider financial and organizational resources . the study design was limited by the availability of the robot and could be remedied by a future prospective randomized study . as mentioned previously , the additional costs incurred when using the robot are a prohibitive factor , especially at an urban academic medical center such as ours that typically treats underinsured patient populations . furthermore , right hemicolectomy was the predominantly performed operation in this study , a procedure that is technically less challenging than an apr , for example . as such , this has a number of implications regarding operative time , blood loss , and perioperative and postoperative complications . although our study is a small retrospective comparison and thus subject to the limitations of such a study , it presents promising data on the efficacy of robotic surgery at institutions similar to ours . further investigation into the comparative costs and into the magnitude of the effects in a larger patient population is necessary to better elucidate the differences between laparoscopic and robot - assisted techniques in colon and rectal operations . in our early experience , the robotic - assisted technique is a safe and efficacious approach to colorectal surgery , in addition to preserving oncologically sufficient outcomes .
background and objectives : over the years , there has been a continual shift toward more minimally invasive surgical techniques , such as the use of laparoscopy in colorectal surgery . 
 recently , there has been increasing adoption of robotic technology . 
 our study aims to compare and contrast robot - assisted and laparoscopic approaches to colorectal operations.methods:forty patients undergoing laparoscopic or robotic colorectal surgery performed by 2 surgeons at an academic center , regardless of indication , were included in this retrospective review . 
 patients undergoing open approaches were excluded . 
 study outcomes included operative time , estimated blood loss , length of stay , complications , and conversion rate to an open procedure.results:twenty-five laparoscopic and fifteen robot - assisted colorectal surgeries were performed . 
 the mean patient age was 61.1  10.7 years in the laparoscopic group compared with 61.1  8.5 years in the robotic group ( p = .997 ) . 
 patients had a similar body mass index and history of abdominal surgery . 
 mean blood loss was 163.3  249.2 ml and 96.8  157.7 ml , respectively ( p = .385 ) . 
 operative times were similar , with 190.8  84.3 minutes in the laparoscopic group versus 258.4  170.8 minutes in the robotic group ( p = .183 ) , as were lengths of hospital stay : 9.6  7.3 and 6.5  3.8 days , respectively ( p = .091 ) . 
 in addition , there was no difference in the number of lymph nodes harvested between the laparoscopic group ( 14.0  6.5 ) and robotic group ( 12.3  4.2 , p = .683).conclusions : in our early experience , the robotic approach to colorectal surgery can be considered both safe and efficacious . 
 furthermore , it also preserves oncologically sufficient outcomes when performed for cancer operations .