Orthotopic Urinary Diversion in the Female Patient

Orthotopic reconstruction offers the most natural voiding pattern after radical cystecomty, allowing voluntary micturition through the intact native urethra. Several pathologic reviews have demonstrated that with careful selection of appropriate patients, a portion of the female urethra can be preserved for orthotopic reconstruction. Performing minimal dissection anteriorly, and avoiding injury of the pudendal innervations to the rhabdosphincter is crucial in maintaining the midurethral continence mechanism in female patients with neobladders.

The evolution of urinary diversion after radical cystectomy has been impressive over the past century. The ideal form of diversion has yet to be determined, but orthotopic reconstruction offers the most natural voiding pattern, allowing voluntary micturition through the intact native urethra. It has been estimated that more than 50% of patients with invasive bladder cancer are suitable candidates for orthotopic urinary diversion. Before 1990, orthotopic reconstruction was contraindicated in female patients undergoing cystectomy based on two assumptions: (1) Complete removal of the urethra is necessary to provide an adequate surgical margin, and (2) female patients are unable to maintain continence after diversion with an orthotopic neobladder.

Initial concern regarding the possible high urethral recurrence rate has been allayed. Several pathologic reviews have demonstrated that with careful selection of appropriate patients, a portion of the female urethra can be preserved for orthotopic reconstruction. These studies determined that tumor involving the bladder neck is the most significant risk factor for urethral tumor involvement; however, approximately 50% of women with tumor at the bladder neck had a urethra that was free of tumor. Intraoperative frozen-section analysis of the distal surgical margin (proximal urethra) was found to be an accurate and reliable means for evaluation of the proximal urethra and is the recommended selection criteria for performing an orthotopic diversion in female patients. Because the final decision about the use of orthotopic diversion to the urethra can be influenced by the results of intraoperative frozen sections, patients should be advised of alternative diversion methods before surgery.

Initial concerns about the integrity of the female continence mechanism in cases of urethra-sparing cystectomy also have been allayed. A more comprehensive understanding of the female urethra and continence mechanism has been gained through anatomic and histologic studies of the female pelvis. A transition from smooth muscle to striated muscle in the midurethra to the distal third of the urethra has been described. Performing minimal dissection anteriorly and avoiding injury of the pudendal innervation to the rhabdosphincter is crucial in maintaining the midurethral continence mechanism in female patients with neobladders. Maintenance of the urethral support structures may contribute to preserving continence. Preservation of the endopelvic fascia and the pubourethral ligament anterior to the bladder neck and rhabdosphincter is important in maintaining the appropriate anatomic relationships as the urethra courses across the pelvic floor. This support system is augmented by the infrapelvic fascia (levator ani and pubococcygeus muscles) and by the connective supporting tissues of the anterior vaginal wall surrounding the urethra. Dissection of the cystectomy specimen off of the anterior vaginal wall may assist in maximizing preservation of support structures and innervation to the anterior urethra, factors that may be important in maintaining passive and voluntary urinary control.

Known complications of orthotopic neobladder substitution in females are incomplete voiding and neobladder–vaginal fistula. Urinary retention largely has been attributed to posterior displacement of the pouch with acute urethrointestinal angulation. Reported neobladder–vaginal fistulae were found in areas where the vaginal closure suture line overlapped suture lines of the neobladder. The incidence of both of these complications can be decreased by the use of an anterior vaginal-wall–sparing approach to cystectomy.

Knowledge that the urethra and continence mechanism can be preserved safely in female patients undergoing cystectomy has enabled orthotopic lower urinary reconstruction to become a viable and preferred method of diversion at many centers. The authors advocate an anterior vaginal-wall–sparing technique for cystectomy with orthotopic diversion. They believe that this approach achieves adequate oncologic results while preserving necessary support structures and possibly decreasing the incidence of certain complications.

Preoperative preparation

Female patients who are considered to be candidates for orthotopic neobladder substitution after cystectomy should meet criteria for an anterior vaginal-wall–sparing approach. Patients should undergo preoperative bimanual pelvic examination to allay any suspicion for direct invasion into the vaginal wall. CT scan of the abdomen and pelvis may be helpful to rule out evidence of direct invasion into the reproductive organs. Metastatic evaluation should be performed in all patients according to standards.

Technique

The superior, posterior, and lateral pedicles of the bladder are isolated and ligated to the level of the anterior vaginal wall using a right angle and ties or locking surgical clips ( Fig. 1 ). A sponge stick is placed in the vaginal vault and elevated cephalad to assist in identification of the apex and anterior wall of the vagina. The bladder is elevated to reveal the peritoneal cul-de-sac, where the impression of the sponge stick can be palpated. The approximate location of the plane between the anterior vaginal wall and the posterior bladder is identified, and the overlying peritoneum is incised with electrocautery ( Fig. 2 ). If present, the uterus may be preserved, in which case the plane to be developed is located just caudad to the cervix. If the patient wants to undergo a hysterectomy, the cervix is excised completely. The open ends of the vaginal apex are approximated with absorbable Vicryl suture. The authors recommend that a flap of omentum be secured to cover the oversewn vaginal apex, eliminating the possibility of overlapping suture lines. With continued cephalad elevation of the vaginal wall, the central plane between bladder and vagina is developed with a combination of sharp and blunt dissection. Lateral attachments can be taken down with the assistance of a vessel-sealing ligasure device ( Fig. 3 ). Careful dissection in this plane is paramount to avoid inadvertent entry into the specimen or injury to the vaginal wall. The bladder specimen is elevated out of the pelvis as this carefully developed posterior plane is continued to the level of the bladder neck ( Fig. 4 ). Palpation of the Foley catheter balloon in the bladder helps to identify this stopping point. Any additional distal dissection is discouraged because of the potential disruption of the musculofascial support or innervation of the rhabdosphincteric complex. Attention then is directed to the anterior dissection. Minimal dissection should be performed anteriorly to prevent injury to the distal sphincteric mechanism. The bladder neck can be identified by palpation of the Foley catheter balloon, and an incision is made just distal to this area, exposing the Foley catheter ( Fig. 5 ). The urethra is incised completely, and any remaining fibromuscular tissue that is attached to the urethra or perineal body is divided, freeing the specimen for removal. The endopelvic fascia anterior to the rhabdosphincter is not disturbed ( Fig. 6 ). Bleeding from the dorsal vein is usually minimal and can be controlled with suture ligatures placed anterior to the urethra. Absorbable sutures are used to control collateral vaginal wall bleeding that cannot be stopped adequately with electrocautery. The posterior bed of resection is inspected carefully to ensure that no defects in the anterior vaginal wall have been created. Incidental incisions are closed primarily in multiple layers with absorbable Vicryl suture. If possible, a flap of omentum should be secured over the repair to discourage fistula formation. The neobladder is created in accordance with surgeon preference, and 45 to 60 cm of small intestine usually is employed. The authors’ preferred configuration is a W-shaped pouch that provides a good-capacity spherical reservoir. Five to six 2-0 Vicryl sutures that are placed circumferentially around the urethral stump are used to anchor the most dependent segment of the constructed neobladder to the urethra ( Fig. 7 ).