The sigmoidorectal pouch (Mainz pouch II).

A sigmoidorectal pouch was constructed in 20 patients (18 with invasive bladder cancer, 2 with complete urethral destruction with multiple vesicovaginal fistulas). The rectal-dynamic studies showed that by detubularization and reconfiguration of the sigmoid colon and rectum, we obtained a low-pressure reservoir, with the high-pressure contractions eliminated. Preoperatively, the basal rectum pressure was 21.4 cm H2O; rectum contractions reached a mean of 27.6 cm H2O (maximum 48 cm H2). Postoperatively (9-36 months) the mean basal pressure of the pouch was 19.3 cm H2O (p > 0.05; t test comparison with the preoperative value), with a mean contraction value of 19.1 cm H2O (p < 0.05). All the patients experienced continence day and night with a pouch emptying frequency of four times during the day and once at night, after 9 months. By fixing the pouch to the promontory or psoas muscle, without compromising the blood supply to the pouch, the risk of ureteral kinking and upper urinary tract dilatation were considerably decreased. The price to be paid for almost perfect continence was hyperchloremic acidosis in most patients.