Decreased sensitivity in the membranous urethra after orthotopic ileal bladder substitute

Purpose: The effect of cystoprostatectomy with orthotopic substitution on m embranous urethral sensation and subsequent urinary continence is unknown. We determined the sensory threshold for electrical stimulation of the membr anous urethra and correlated it with continence, nerve sparing surgical tec hnique and potency. Materials and Methods: The sensory threshold was measured in a control grou p of 35 men before radical prostatectomy or cystoprostatectomy and in 47 me n after cystoprostatectomy and ileal bladder substitution. Results: The sensory threshold of the membranous urethra was 9 +/- 2 in the control group compared to 27 +/- 11 mA. in the postoperative group (p < 0. 001). Patients with daytime continence had a threshold of 24 +/- 9 compared to 39 +/- 10 mA. in incontinent patients (p < 0.001). We were unable to sh ow any correlation between the sensory threshold in patients with (25 +/- 1 0 mA.) and without (31 +/- mA.) attempted nerve sparing surgery (p = 0.1) n or between potent (25 +/- 12 mA.) and impotent (27 +/- 11 mA.) patients (p = 0.4). Conclusions: Sensitivity in the membranous urethra decreased in patients af ter cystoprostatectomy and ileal bladder substitution. Urethral sensitivity in the sphincter area was better in continent than incontinent patients. S ince we were unable to find any correlation between the sensory threshold a nd nerve sparing surgery or potency, it may be assumed that at least part o f the sensory fibers to the membranous urethra pass through the pudendal ne rve and/or the intrapelvic extrapudendal nerve fibers.