Comparing Force of Stream With a Standard Fill Voiding Trial After Surgical Repair of Apical Prolapse A Randomized Controlled Trial

OBJECTIVE: To estimate whether the urinary force of stream method is noninferior to a standard fill voiding trial for rate of catheterization within 6 weeks after apical prolapse surgery in those discharged without a catheter. METHODS: A noninferiority randomized controlled trial was conducted in postoperative women comparing force of stream with standard fill voiding trials after vaginal, abdominal, or laparoscopic-robotic apical pelvic organ prolapse (POP) surgery. Before discharge, women in both groups were backfilled with 300 mL normal saline. Successful voiding criteria in the force of stream group was subjective force of stream of at least 50 using a visual analog scale; reporting less than 50 prompted a bladder scan. Successful voiding was defined as a postvoid residual volume of less than 500 mL. For the standard fill voiding trial group, voiding two thirds of the instilled amount indicated success. The primary outcome was the rate of catheterization within the 6-week postoperative period after surgical repair of apical prolapse among those discharged without a urinary catheter. Secondary endpoints included trial of void failure rates. A sample size of 59 patients per group who passed trial of void at discharge was needed to achieve 80% power using a noninferiority margin (delta of 10%). Total enrollment of 169 patients was necessary to account for an estimated 30% trial of void failure rate. RESULTS: From April 2016 and April 2017, 184 patients were enrolled (six enrolled before the trial registration date), with the first patient enrolled on April 1, 2016. One hundred seventy-four patients were randomized (86 in the force of stream group and 88 in the standard fill voiding trial group). No differences were observed in demographic or perioperative characteristics, except for stage 2 apical prolapse (52% in the force of stream group vs 36% in the standard fill voiding trial group). For the primary outcome, similar rates were found in those patients who passed their trial of void but subsequently needed catheterization for voiding dysfunction (force of stream 2.8% [2/71] vs standard fill voiding trial 3.1% [2/64]; difference 20.3%, 95% CI 28.69% to 8.08%). The incidence of trial of void failures at discharge was similar (force of stream 17.4% [15/ 86] vs standard fill voiding trial 26.4% [23/87]; risk ratio 0.65, 95% CI 0.37-1.18, P=nonsignificant). CONCLUSION: Force of stream was noninferior to standard fill voiding trial when comparing the rate of catheter insertion during the 6-week postoperative period after apical POP surgery in those discharged without a catheter.