Spontaneous Void Requirements for Patients Undergoing Ambulatory Anorectal Surgery
Phase: NA
Conditions: Complications, Postoperative
Sponsor: Syed Husain

PI: Syed Husain, MD 
 
 
 
 
Version 2/20/2018 
 
 
 
 
 
 
 
 
 
 
IRB #: 2018H0208 
 
 
 
 
 
 
 
 
 
 
Approved: 5/31/18 
1 
 
Spontaneous Void Requirements for Patients Undergoing Ambulatory Anorectal Surgery 
 
 
 
 
TABLE OF CONTENTS 
OBJECTIVE 
 
2 
BACKGROUND & RESEARCH SIGNIFICANCE 
 
2-3 
HYPOTHESIS 
 
PRIMARY & SECONDARY OBJECTIVES 
 
3 
 
3 
STUDY PLAN & PROCEDURES 
 
3 
INCLUSION/EXCLUSION CRITERIA 
 
3 
MEASUREMENT OF STUDY VARIABLES  
 
4-5 
 
STATISTICAL ANALYSIS 
 
5 
FUNDING 
 
6 
BIBLIOGRAPHY 
 
6 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 

PI: Syed Husain, MD 
 
 
 
 
Version 2/20/2018 
 
 
 
 
 
 
 
 
 
 
IRB #: 2018H0208 
 
 
 
 
 
 
 
 
 
 
Approved: 5/31/18 
2 
Objective 
 
Urinary retention is a common complication following anorectal surgery and is thought to be 
multifactorial. Some researchers explain post-operative urinary retention as a consequence of 
long acting analgesics which dampen the ability for bladder fullness1. Others point to irritation to 
pelvic nerves that function with micturition thus blunting pain evoked reflexes2,3. Modifiable 
factors that have been found to play a role in contributing to post-operative urinary retention 
include the use of intravenous fluids over one liter during surgery, and administration of local 
analgesics. Local analgesics provide significant acute pain relief, but contribute to the theory of 
blunted pain reflexes.  Inadequate pain control increases likelihood of urinary retention through 
inability of perineal relaxation. A balance must be maintained between adequate pain control 
and interfering with the micturition reflex. Non-modifiable risk factors include age, female sex, 
the presence of diabetes mellitus, and specific surgical procedure4. 
 
Complications of post-operative urinary retention include an increase in urinary tract infections, 
hospital readmission, damage to detrusor contractility, and for the elderly increased confusion 
and delirium5. The rate of urinary retention post anorectal surgery is between 16-20%. The 
incidence of urinary retention following high-risk ambulatory surgery is stated to be 5%. The 
objective of this study is to assess if not requiring patients to spontaneous void prior to 
discharge from the post-anesthesia care unit (PACU) will result in shorter lengths of stay in the 
post-anesthesia care unit without increasing hospital readmissions or emergency room visits. 
 
Background & Research Significance 
 
Spontaneous void is a discharge criteria from post anesthesia care units given the potential 
need for bladder catheterization and prolonged hospitalization for urinary retention. Research 
evaluating required spontaneous void following ambulatory anorectal surgery is lacking. 
Research has been conducted on patients requiring spinal and epidural anesthesia which 
demonstrated that requiring spontaneous voiding post-operation is unnecessary and delays 
discharge times 4. Previous research regarding post-operative urinary management of anorectal 
procedures classified them as ‘high-risk’ with other procedures5. Researchers have sought to 
address potential risk factors for urinary retention and discuss restriction of pre-operative, 
perioperative fluid, and adequate pain control to decrease the incidence1,2,6,7. Determining 
factors that specifically guide discharge for patients undergoing anorectal surgery and the 
necessity of post-operative void, however, has not been previously evaluated.  
 
Currently the protocol at The Ohio State University Hospital requires voiding spontaneously 
prior to discharge from the PACU, but operations performed at The Ohio State University 
Hospital East do not require a spontaneous void prior to discharge. A recent IRB approved 
study conducted by our group examined if requiring a spontaneous void prior to discharge 
affects emergency room visits and readmission rates. We conducted a retrospective review of 
ambulatory anorectal surgeries performed at the two locations. One of these locations required 
the ability to void spontaneously as a prerequisite for discharge after ambulatory anorectal 
surgeries (spontaneous void group) whereas the other location did not maintain this requirement 

PI: Syed Husain, MD 
 
 
 
 
Version 2/20/2018 
 
 
 
 
 
 
 
 
 
 
IRB #: 2018H0208 
 
 
 
 
 
 
 
 
 
 
Approved: 5/31/18 
3 
and patients were discharged once they were deemed ready (no void group). Our research 
concluded that patients can be safely discharged without voiding after anorectal procedures 
without increasing the risk of ED visits or readmissions. Furthermore, a requirement to 
spontaneously void before discharge significantly prolongs PACU stays. Thus, we propose to 
compare PACU discharge times between patients requiring a spontaneous void to those 
patients not requiring a spontaneous void.  
 
Hypothesis: 
Ability to void spontaneously after anorectal procedures does not result in reduced 
readmissions, emergency room visits and post op complications.  
 
Primary Objectives: 
1. To compare readmission and complications rates between patients who are required to 
void post anorectal surgeries to those who are sent home without voiding 
spontaneously. 
2. To compare the rates of emergency room visit between patients who are required to void 
post anorectal surgeries to those who are sent home without voiding spontaneously. 
 
Secondary Objectives: 
1. To compare PACU times for patients who are required to void post anorectal surgeries 
to those who are sent home without voiding spontaneously.  
2. To compare total hospital costs for patients who are required to void post anorectal 
surgeries to those who are sent home without voiding spontaneously. 
 
Study Plan and Procedures 
This study will be a prospective clinical trial, in which 100 anorectal surgery patients will be 
randomly assigned to a control (spontaneous void) or experimental (no void) group. 
Randomization will be done using the free software provided by www.randomizer.org. 
“Spontaneous void” group will include 50 patients who will required to void spontaneously after 
anorectal surgeries. On the other hand “no void” group will be 50 patients who will be 
discharged home from the PACU once they meet ambulatory surgery center discharge criteria 
per hospital guidelines. Patients requiring anorectal surgeries will be consented to take part in 
the study during the preoperative outpatient office visit. A post op phone call will be made by 
designated study personnel to participants on post-op day 30 using a study questionnaire to 
assess re-admission and emergency room visits.  
 
Inclusion Criteria: 
1. Age 18-80 years old 
2. Patients undergoing hemorrhoidectomy, fistulotomy or anal condyloma excision. 
 
Exclusion Criteria: 
1. Age <18 yo or >80 yo 
2. Prisoners 
3. Pregnant Women 

PI: Syed Husain, MD 
 
 
 
 
Version 2/20/2018 
 
 
 
 
 
 
 
 
 
 
IRB #: 2018H0208 
 
 
 
 
 
 
 
 
 
 
Approved: 5/31/18 
4 
4. Unable or unwilling to follow the study protocol or any reason the research team believes 
the subject is not an appropriate candidate for this study 
 
Measurements of Study Variables 
 
To achieve the study goals, the following data will be collected: 
 
Pre-operative Data: 
1. Demographics: age, sex, height, weight, BMI, race 
2. Insurance type 
3. Past medical history 
4. Diabetes history 
5. Hemoglobin A1C 
6. Coronary artery disease 
7. Chronic obstructive pulmonary disease 
8. Inflammatory bowel disease 
9. Diagnosis of cancer 
10. Renal dysfunction 
11. Past surgical history 
12. Steroid use 
13. Immunosuppression 
14. Smoking history  
15. Substance abuse 
16. Diagnosis 
17. ASA class 
18. Elixhauser comorbidity index 
19. Hospital Cost 
 
Post-Operative: 
1. Procedure CPT 
2. Where procedure took place 
3. Date of procedure 
4. Length of procedure 
5. Estimated blood loss 
6. Reoperation during index admission 
7. Diagnosis of Urinary retention  
8. Post-operative complications  
9. Length of hospital stay in days 
10. ICU admission 
11. ED visit 
12. Readmission 
13. Interval to last follow up in days 
14. Blood transfusion requirements 
15. Total IV fluids received 

PI: Syed Husain, MD 
 
 
 
 
Version 2/20/2018 
 
 
 
 
 
 
 
 
 
 
IRB #: 2018H0208 
 
 
 
 
 
 
 
 
 
 
Approved: 5/31/18 
5 
16. Total pain medicine received 
17. Hospital Cost 
 
Post-Operative Phone Call: 
1. Emergency department visit, urgent care visit, or admission outside of The Ohio State 
University Wexner Medical Center within 30 days post-operative 
2. Reason for admission, emergency department visit, or urgent care visit 
 
 
Schedule of Events 
 
Pre-Operative Appointment 
30 Days Post-Operative  
Assess Eligibility Criteria X 
  
Informed Consent 
X 
  
Pre-Op Data 
X 
  
Post-Op Phone Call 
 
X 
Post-Op Data 
 
X  
 
Statistical Analysis 
 
Data will be expressed using means +/- standard deviations in addition to sample size (n) and 
percentages. Further statistical analysis will include Students t test for quantitative variables and 
chi squared test for comparisons of qualitative variables. A p value <0.05 will be used for 
statistical significance.  
 
Sample Size Calculation: 
 
Power N1 
N2 
μ1 
μ2 
μ1 - μ2 σ1 
σ2 
Alpha Beta 
0.80000 
50 
50 
210.0 129.1 80.9 
100.0 175.0 0.050 0.20000 
0.80000 
75 
75 
210.0 144.3 65.7 
100.0 175.0 0.050 0.20000 
0.80000 
100 
100 
210.0 153.2 56.8 
100.0 175.0 0.050 0.20000 
 
Report Definitions 
Power is the probability of rejecting a false null hypothesis. 
N1 and N2 are the number of items sampled from each population. 
μ1 and μ2 are the assumed population means for power and sample size calculations. 
μ1 - μ2 is the difference between population means at which power and sample size 
calculations are made. 
σ1 and σ2 are the assumed population standard deviations for groups 1 and 2, respectively. 
Alpha is the probability of rejecting a true null hypothesis. 
Beta is the probability of accepting a false null hypothesis. 

PI: Syed Husain, MD 
 
 
 
 
Version 2/20/2018 
 
 
 
 
 
 
 
 
 
 
IRB #: 2018H0208 
 
 
 
 
 
 
 
 
 
 
Approved: 5/31/18 
6 
Summary Statements 
Group sample sizes of 50 and 50 are needed to achieve 80.000% power to reject the null 
hypothesis of equal means when the population mean difference is μ1 - μ2 = 210.0 - 129.1 = 
80.9 with standard deviations of 100.0 for group 1 and 175.0 for group 2, and with a significance 
level (alpha) of 0.050 using a two-sided two-sample unequal-variance t-test.  
 
For other categorical variables, such as readmission rates, frequencies will be summarized.  
 
Funding 
 
A medical student has applied for a Roessler Scholarship for Summer 2018, and an additional 
medical student will receive college credit as an extracurricular activity for their work on this 
project. 
 
Bibliography 
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Petros JG, Bradley TM. Factors influencing postoperative urinary retention in patients 
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2.  
Kunitake H, Poylin V. Complications Following Anorectal Surgery. Clin Colon Rectal 
Surg. 2016;29(1):14-21. doi:10.1055/s-0035-1568145. 
3.  
Sutherland LM. A Systematic Review of Stapled Hemorrhoidectomy. Arch Surg. 
2002;137(12):1395. doi:10.1001/archsurg.137.12.1395. 
4.  
Toyonaga T, Matsushima M, Sogawa N, et al. Postoperative urinary retention after 
surgery for benign anorectal disease: Potential risk factors and strategy for prevention. Int 
J Colorectal Dis. 2006;21(7):676-682. doi:10.1007/s00384-005-0077-2. 
5.  
Darrah DM, Griebling TL, Silverstein JH. Postoperative Urinary Retention. Anesthesiol 
Clin. 2009;27(3):465-484. doi:10.1016/j.anclin.2009.07.010. 
6.  
Mulroy MF, Salinas F V, Larkin KL, Polissar NL, Ph D. Ambulatory Surgery Patients May 
Be Discharged before Voiding after Short-acting Spinal and Epidural Anesthesia. 
Anesthesiology. 2002;(97):315-319. 
7.  
Pavlin DJ, Pavlin EG, Fitzgibbon DR, Koerschgen ME, Pitt TM. Management of Bladder 
Function after Outpatient Surgery. Anesthesiology. 1999;91:42-50. 
doi:10.1097/PRS.0000000000001335. 
8.  
Bailey H, Ferguson J. Prevention of urinary retention by fluid restriction following 
anorectal operations. Dis Colon Rectum. 1976;19(3):250-252. 
9.  
Baldini G, Bagry H, Aprikian A, Carli F. Post Operative Urinary Retention. 
Anesthesiology. 2009;(110):1139-1157. doi:10.1017/S0003581500073893. 
10.  
Zaheer S, Reilly WT, Pemberton JH, Ilstrup D. Urinary retention after operations for 
benign anorectal diseases. Dis Colon Rectum. 1998;41(6):696-704.