Bulboprostatic anastomotic urethroplasty with preservation of potency: Anatomical study, operative approach and clinical results

Abstract

OBJECTIVE. To identify the precise anatomy of the membranous and bulbous urethrae and their relation to the neurovascular bundles (cavernous nerves and vessels). Based on the findings, a modified surgical technique was developed to preserve potency by avoiding injury to the neurovascular bundles during surgery on the posterior urethra. The material for this study consisted of 10 male cadavers. We injected eight cadavers with a mixture of red latex and lead oxide. By means of meticulous dissection we removed the bladder, prostate, urethra, penis, surrounding vessels and nerves. We also identified the anatomical relations between various urogenital structures and the vessels and nerves. We examined the specimens radiologically. In the other two cadavers, we removed the membranous urethrae and subjected them to histological examination. We used haematoxylin-eosin and Verhoeff von Gieson stains to study the elastic tissues. The membranous urethra measured 2.5-3 cm in length. It originated from the lower third of the anterior surface of the prostate (and not from the apex) as a continuation of the prostatic urethra. The wall of the membranous urethra contained abundant elastic fibres. The neurovascular bundles were located posterolateral to the mid-portion of the prostate and prostatic apex. Near the apex the neurovascular bundle divided into two parts: a larger anterior part and a smaller posterior part. The anterior part crossed the membranous urethra, then the bulb of the penis at the 1 and 11 o'clock positions and finally entered the corpus cavernosum. The posterior part crossed the membranous urethra more posteriorly to enter the bulb of the penis. Between 1992 and 2003 we managed 22 patients (age range 16-50 years) with posterior urethral obstruction secondary to pelvic fracture by means of bulboprostatic anastomosis. We managed 17 patients via the perineal route and five via a combined perineoabdominal-transpubic route. All of these patients were potent before the operation, which proved the integrity of the neurovascular bundles. We could spare the anterior divisions of the neurovascular bundles (greater cavernous nerves and vessels) during their crossing of the bulb of the penis by cutting and dissecting within the bulb (not outside it) before dismembering it from the urogenital diaphragm. We also refrained from any dissection of the apex and the posterolateral surfaces of the prostate to avoid injury to the neurovascular bundles. At 6-year follow-up (range 1-10 years) 21/22 patients preserved their potency, giving a success rate of 95.45%. Of the 22 patients, two became temporarily impotent after the operation but regained potency within a period of 4-6 months. Our technique of neurovascular bundle preservation during bulboprostatic anastomotic urethroplasty may solve the problem of postoperative impotence.