Detailed histological investigation of the female urethra: application to radical cystectomy

Purpose: We histologically examined the urethral anatomy to assess whether the surgical procedure for radical cystectomy should be modified in females.

Materials and methods: Anatomical and histological studies were performed on 20 adult female cadavers. Semiserial sections were processed for histological examination and immunohistochemistry. To assess the clinical value of the antegrade approach we examined blood loss and function in 12 consecutive patients who underwent radical cystectomy by this approach.

Results: Vaginal wall smooth muscle contributed to urethral wall formation, in addition to a thin layer of proper urethral smooth muscle, particularly when the bladder detrusor was poorly developed or degenerated. The middle urethra was attached tightly to the vaginal smooth muscles with abundant veins running at the interface. The urethral sphincter and its inferoposterior continuation (urethrovaginal sphincter) were embedded in the elastic fiber rich perineal membrane. The membrane was U shaped, wrapping around the anterior aspect of the middle urethra and extending posterior along the distal vagina to end at the lateral extension of the perineal body near the external anal sphincter. Mean estimated blood loss was 965 ml. Of patients who received a neobladder hypercontinence was observed in 14.3% and 57.1% achieved continence.

Conclusions: There is topographical variation in the anatomy of tissues surrounding the female urethra. Care should be taken when dissecting the tissues dorsal or lateral to the urethra. The antegrade approach is useful since the urethra can be dissected under direct vision and traction can be applied to these structures.