Incorporation and adaptation of intestinal segments into the urinary tract

Background: When urinary diversion began in the past century, urine was diverted to the intestine (internal diversion) and emptying was controlled by the anal sphincter. Later ureterosigmoidostomies became the method of choice. However, despite simplicity of the technique metabolic side effects such as hyperchloremic metabolic acidosis, urinary infection and frequent deterioration of renal function urged the need for new ways of bladder replacement. Methods: Diversions to the skin (external diversion) could avoid to a large extent these drawbacks. In fact, urinary diversion to the skin via an ileal conduit (Bricker) is the most frequently used technique. Recently continent diversions to the urethra (orthotopic pouch) have seen renewed interest. Results: Tunneled implantation of the ureters into the small bowel prevented reflux and recurrent infection. Further, less electrolyte imbalances were noted due to little electrolyte absorption. Since quality of life of the affected individual has become an important issue, continent external diversions are often offered to the young patient, using mostly cecum (or colon) as an internal collecting reservoir and a short segment of ileum for connecting the reservoir to the skin (Indiana pouch, Mainz pouch I). Similarly, orthotopic urinary diversion, connecting the reservoir (pouch) to the urethra has been employed. Frequently the ileum is used to create an ileum neobladder with connection to the urethra (modified Kock pouch, Hautmann bladder and Studer bladder). However, disadvantages of continent diversions are mainly the need for intermittent self catheterization and in case of orthotopic replacements night time incontinence. Nevertheless, the overall goal in the construction of continent reservoirs is the storage of large amounts of urine for a reasonable time period under low pressure conditions (< 40 cm H₂O). Conclusions: From this perspective, the majority of patients undergoing cystectomy for invasive bladder cancer can be offered bladder substitutes providing continence and easy emptying while avoiding external collecting devices.