Sphincteric incontinence: the primary cause of post-prostatectomy incontinence in patients with prostate cancer.

Post-prostatectomy incontinence in patients with cancer of the prostate is often the result of sphincteric injury. However, recent studies have emphasized the role of detrusor instability and decreased bladder compliance in the etiology of post-prostatectomy incontinence. To further clarify the primary cause of incontinence, we reviewed the urodynamic studies of 39 patients referred for evaluation of incontinence after prostatectomy (35 radical, 4 TURP and radiation) for prostate cancer. Multichannel videourodynamic studies were performed to characterize bladder function, and sphincteric incontinence was assessed by Valsalva leak point pressure (VLPP). Flexible cystourethroscopy was used to evaluate the vesicourethral anastomosis. A pad scoring system was used to measure symptom severity. Sphincteric damage was found to be the sole cause of urinary incontinence in 23 patients (59%) and a major contributor in 14 others (36%). Twenty-seven patients (69%) had VLPP less than 103 cmH2O (mean = 55) with a urethral urodynamic catheter in place. An additional 10 (26%) had VLPP less than 150 cmH2O (mean = 63) upon removal of the catheter. VLPP is an indication of the severity of sphincteric damage. The importance of removing the urodynamic catheter during measurement of the VLPP is emphasized. Urethral fibrosis was confirmed by cystourethroscopy in 26 (67%) patients. Bladder dysfunction characterized by detrusor instability and/or decreased bladder compliance was seen in 15 patients (39%). In contrast to previous studies, our results indicate that sphincteric damage, and not bladder dysfunction, accounts for the vast majority of post-prostatectomy incontinence in patients with prostate cancer. However, it is essential to identify and treat bladder dysfunction in order to optimize the outcome of treatment for sphincteric incontinence.