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).