The role of preoperative puborectal muscle function assessed by transperineal ultrasound in urinary continence outcomes at 3, 6, and 12 months after robotic-assisted radical prostatectomy

Abstract

Purpose: The efficacy of pelvic floor muscle training (PFMT) for men with postprostatectomy incontinence (PPI) after robotic- assisted radical prostatectomy (RARP) is controversial and the mechanism for its possible effect remains unclear. The aim of this study was to investigate the relationship between bladder neck (BN) displacement, as a proxy for puborectal muscle activation, and continence outcomes after RARP. Methods: Data were extracted from the South Australian Prostate Cancer Clinical Outcomes Collaborative database for men undergoing RARP by high volume surgeons who attended preoperative pelvic floor physiotherapy for pelvic floor muscle (PFM) training between 2012 and 2015. Instructions were to contract the PFM as if stopping the flow of urine. BN displacement was measured with 2-dimensional transperineal ultrasound, without digital rectal examination. Urinary continence status was assessed preoperatively and at 3, 6, and 12 months using the Expanded Prostate Cancer Index Composite 26. Data were analysed using logistic regression and mixed effects linear modelling. Confounding variables considered were baseline continence, age at diagnosis, margin status, nerve sparing procedures and pathological stage. Results: Of 671 eligible men, 358 met the inclusion criteria and were available for analysis, with 136 complete datasets at 12-month follow-up. While BN movement was associated with preoperative continence, there was no significant effect of BN displacement on the change in urinary continence at 12 months postprostatectomy (P=0.81) or on the influence of time on continence over 3-12 months. Conclusions: Continence outcomes were not associated with BN displacement, produced by activity of the puborectal portion of the levator ani muscle, at 3, 6, or 12 months after RARP. These results suggest that the puborectal muscle does not play a role in the recovery of continence after RARP and may help to explain the negative findings of many studies of PFMT for PPI.