Anesthetics' role in postoperative urinary retention after pelvic organ prolapse surgery with concomitant midurethral slings: a randomized clinical trial

Introduction and hypothesis: Spinal anesthesia can be a potential risk factor for postoperative urinary retention (POUR). Our objective was to compare POUR rates for outpatient vaginal pelvic floor surgeries when using spinal versus general anesthesia. Our hypothesis was that spinal anesthesia would have higher POUR rates compared with general anesthesia. Methods: This was a randomized clinical trial on subjects undergoing outpatient pelvic organ prolapse (POP) surgery with a concomitant midurethral sling (MUS). Subjects were discharged home the same day as surgery. Subjects were excluded if they had a preoperative post-void residual > 150 ml, they were < 40 years of age, surgery was < 1 h, or they had contraindications to spinal or general anesthesia. A standardized voiding trial was performed. The primary aim was to compare POUR rates between anesthesia groups. A power analysis estimated 28 subjects were required per group to detect a 37% difference with 80% power and an alpha of 0.05. Results: The trial was registered at ClinicalTrials.gov on July 15, 2015. Sixty-one subjects were enrolled between June 22, 2015, and December 31, 2017. Three were excluded, leaving 29 in each group. Groups were similar in demographics. For the primary outcome, there was a 14.3% difference in POUR rates between spinal and general anesthesia, which did not reach statistical significance based on our power calculation (p = 0.2516). Conclusions: Based on this study, there is not an increased rate of POUR with the use of spinal anesthesia for POP surgery with MUS. However, since there was a trend toward higher rates of POUR in the spinal group, it is possible that a larger powered study design would be able to detect a statistically significant difference between the groups. Based on these findings, if surgical patients would benefit from spinal anesthesia, the risk of urinary retention should not be considered a reason to not utilize this form of anesthesia. Clinical trial registration: Does spinal anesthesia for prolapse surgery with concomitant sling lead to an increase in urinary retention compared to general anesthesia? https://clinicaltrials.gov/ct2/show/NCT02547155?term=laura+martin&rank=3 (NCT02547155)