Histologic Investigation of the Female Vesicourethral Junction and Adjacent Tissues for Nerve-sparing Radical Cystectomy.

OBJECTIVE

To understand the structures around the vesicourethral junction and to improve functional outcomes after nerve-sparing radical cystectomy with orthotopic urinary diversion for female patients, we histologically elucidated the fibromuscular construction and nerve distribution around the vesicourethral junction.

METHODS

Pelvic specimens containing all the pelvic viscera were obtained from 33 donated female cadavers. Macroslices that included the urethra, the anterior wall of the vagina, and the inferomedial edge of the levator ani muscle were made and performed elastica Masson and immunohistochemical staining. The intraoperative findings were collected in 3 female patients undergoing nerve-sparing radical cystectomy.

RESULTS

In 18 out of the 33 cadavers, smooth muscle mass occupied a space between the urethra and the inferomedial edge of the levator ani muscle and covered the inferior margin of the bladder detrusor. We termed this mass the hiatal smooth muscle. The detrusor nerves entered the bladder, and the cavernous and sphincter nerves ran between the hiatal smooth muscle and vesicourethral junction. The boundary between hiatal smooth muscle and urethral smooth muscle was easily distinguished intraoperatively during dissection of the vesicourethral junction.

CONCLUSION

We found that more than half of elderly women have hiatal smooth muscle between the urethra and inferior edge of the levator ani. Autonomic nerve fibers innervating the urethral sphincter, run between the hiatal smooth muscle and vesicourethral junction in female cadavers with hiatal smooth muscle. When performing female radical cystectomy before neobladder reconstruction, nerve sparing can be reliably performed using the hiatal smooth muscle as a landmark.