Hypothesis That Urethral Bulb (Corpus Spongiosum) Plays an Active Role in Male Urinary Continence

Abstract

The proximal urethral bulb in men is enlarged, surrounds the bulbous urethra, and extends dorsally towards the perineum. During intercourse engorgement takes place due to increased blood flow through the corpus spongiosum. Antegrade ejaculation is facilitated by contraction of the bulbospongiosus muscles during climax. Micturition during sexual stimulation is functionally inhibited. Supporting the bulb may indirectly facilitate continence in a certain subset of patients with postprostatectomy incontinence. During physical activity with increased abdominal pressure, reflex contraction of the pelvic floor muscles as well as the bulbospongiosus muscles occurs to support sphincter function and limit urinary incontinence. Operations to the prostate may weaken urinary sphincter function. It is hypothesized that the distal urinary sphincter may be supported indirectly by placing a hammock underneath the urethral bulb. During moments of physical stress the “cushion” of blood within the supported corpus spongiosum helps to increase the zone of coaptation within the sphincteric (membranous) urethra. This may lead to urinary continence in patients treated by a transobturator repositioning sling in patients with postprostatectomy incontinence. This paper describes the possible role of the urethral bulb in male urinary continence, including its function after retroluminal sling placement (AdVance, AdVance XP® Male Sling System, Minnetonka, USA).

Refined nomogram incorporating standing cough test improves prediction of male transobturator sling success

“…Determining the severity of male SUI is critical to patients and providers in deciding between transobturator sling and AUS, but a significant portion of otherwise well‐selected men fail sling despite use of PPD‐based cutoffs . Other potential risk factors for sling failure have been studied attempting to predict a degree of residual urinary sphincteric function . We present a novel non‐invasive clinical tool incorporating the physical demonstration of SUI, represented as SCT grade, in conjunction with baseline PPD use, and history of pelvic radiation which was superior to PPD alone in identifying ideal sling candidates.…”

“…20 Other potential risk factors for sling failure have been studied attempting to predict a degree of residual urinary sphincteric function. 21,22 We present a novel non-invasive clinical tool incorporating the physical demonstration of SUI, represented as SCT grade, in conjunction with baseline PPD use, and history of pelvic radiation which was superior to PPD alone in identifying ideal sling candidates. The nomogram developed from this multivariable model performs optimally at a risk threshold of ≤30% of sling failure, implying that patients who score above this value should be counseled on AUS rather than sling.…”

Magnetic resonance imaging as an assessment tool following intervention with an AdVance XP suburethral sling for postprostatectomy urinary incontinence

“…This relationship in the location of both structures was already described in the MRI saggital T2 . Rehder et al defined the proximal male urethral bulb as an integrated part of the urinary continence mechanism, in which the sling (causing an indentation in the corpus spongiosum) holds on like a hammock during moments of increased physical activity. Our results now correlate success of the surgery with correct placement of the sling.…”

The role of male slings in post prostatectomy incontinence: ICI‐RS 2015

“…Although other transobturator systems, without significant mobilization of the bulb, appear to be compressive urethral slings by the nature of their implantation technique, flow rates, when assessed, do not alter significantly. A recent review has hypothesized that the bulbar urethra corpus spongiosum plays an active role in male continence and that the passage of transobturator MS will augment sphincter function by increasing the zone of coaptation of the sphincter . It is thought that the majority of other transobturator MS may work in this fashion.…”