Rectosigmoid Pouch

The rectosigmoid pouch (Mainz Pouch II), first described by Fisch et al. in 1993, is distinct from the largely abandoned ureterosigmoidostomy. Serious hyperchloremic metabolic acidosis, recurrent pyelonephritis, renal calculi, and the development of secondary malignancies at the anastomosis were responsible for aversion to the classic ureterosigmoidostomy. For the Mainz II pouch, the bowel is left in continuity, the colon is detubularized along its antimesenteric border proximal and distal to the rectosigmoid junction, and a pouch is created using a side-to-side anastomosis. The pouch is fixed to the sacral promontory, and a competent anal sphincter provides the continence mechanism. Fisch demonstrated in a series of 47 patients that a low-pressure system is achieved, and all but one patient was continent day and night.

This option is particularly well suited for patients with contraindications to urethral anastomosis, precluding safe creation of an orthotopic neobladder.

The Mainz II pouch is a well-accepted alternative in women in Europe, the Middle East, and North Africa. Contraindications to the rectosigmoid pouch include: (i) incompetent anal sphincter, (ii) distal colonic disease (polyps, diverticuli), (iii) prior radiation, and (iv) planned radiation.

In a porcine model, Trinchieri et al. described the first experimental laparoscopic construction of a ureterosigmoidostomy. An antirefluxing ureteroileal anastomosis was created along the taenia coli. In 1995, Anderson and colleagues performed laparoscopic rectosigmoid pouch continent urinary diversion in 10 pigs. In this series, pouch creation and bilateral ureteral anastomoses were performed extracorporeally. Mean operative time was 122 minutes, and the pouches performed well (maximal pressure <20 cmH^O, capacity 360 cm3). They had disappointing results, however, with regard to calculi formation on exposed titanium staple line, as well as ureteroenteric anastomotic strictures. In order to test ureteral anastomotic techniques, the authors performed different techniques on each side. The right ureteral anastomosis used an antirefluxing "dunk" technique where 1 cm of distal ureter is passed though an enterotomy and the ureteral adventitia is tacked to the bowl serosa externally. Postoperatively, 11% of these became obstructed. The left ureter was anastomosed in a simple end to side fashion, and 33% of these stenosed. No stents were used in either case.

Denewer et al. employed the same technique in a clinical series of 10 patients. After completing the cystectomy, an 8 cm infraumbilical mini-laparotomy was used to perform a side-to-side sigmoid pouch (stapling technique) with an intussuscepted antireflux valve. Mean operative time was 160 minutes for the laparoscopic portion and 55 minutes for the continent pouch. The staple line was not assessed postoperatively for stone formation.

In 2000, Tuerk et al. were the first to report laparoscopic radical cystectomy with rectosigmoid pouch entirely intracorporeally in five patients. Mean operative time was 7.4 hours, with average blood loss of 245 mL. All patients were discharged postoperatively by day 10, and all reported complete daytime and night time continence. The pouch was constructed using absorbable suture in lieu of stapling to avoid the risk of staple line stone formation. The distinct advantage of this technique over open-assisted counterparts is transanal specimen retrieval following bowel detubularization, or via the opened vagina in women, avoiding an abdominal incision. Furthermore, the sig-moid and rectum have posterior attachments that keep them still and facilitate laparo-scopic suturing. The length of suture lines is also significantly less than for an ileal neobladder.

Concerns over carcinogenesis warrant specific attention in this context. Atta described the preliminary results in 15 patients with a detubularized ureterosigmoi-dostomy and demonstrated that patients passed urine and feces separately. Although the reservoir described by Atta differs slightly from the Mainz II, in that the detubu-larization extends to the rectal ampulla and the left colon orifice is fixed in continuity with the posterior wall of the rectal ampulla. However, our clinical experience has shown that many patients with the Mainz II pouch report separate passage of urine and feces as well. The risk of interval development of adenocarcinoma, therefore, is theoretically lower. Surveillance pouchoscopy should still be employed until more data are available.

The Mainz II pouch is a well-accepted alternative in women in Europe, the Middle East, and North Africa. Contraindications to the rectosigmoid pouch include: (i) incompetent anal sphincter, (ii) distal colonic disease (polyps, diverticuli), (iii) prior radiation, and (iv) planned radiation.

In 2000, Tuerk et al. were the first to report laparoscopic radical cystectomy with rectosigmoid pouch entirely intracorporeally in five patients.

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