Terminal nerve distribution to the urethra and bladder neck: considerations in the management of stress urinary incontinence.
PURPOSE: Recent reports have suggested an increased incidence of intrinsic sphincter dysfunction, most of which seems to appear following the failure of a previous, usually vaginal, surgical repair. Our studies attempt to define more precisely the neuroanatomical relationships that exist in the region of the bladder neck and proximal urethra, and between the urethra and anterior vaginal wall. MATERIALS AND METHODS: We dissected the pelves of adult female cadavers and step sectioned them at 4 mm. intervals. Several staining methods were used on each section to identify and document the position of the nerves and vascular structures between the vaginal wall and urethra. RESULTS: A rich plexus of blood vessels and nerves with ganglia is located between the vaginal wall, and the proximal urethra and bladder neck. The greatest concentrations of nerves are in the 4 o'clock and 8 o'clock positions but nerve fibers are identified throughout the loose areolar tissue planes through which vaginal surgery for stress urinary incontinence is often performed. CONCLUSIONS: When performing surgical procedures for the correction of stress urinary incontinence, the possibility that denervation and devascularization of the terminal urethra and bladder neck secondary to surgical dissection could contribute to the subsequent development of intrinsic sphincter dysfunction should be considered.