Urinary Diversion: Ileal Conduit to Neobladder

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Abstract
The goals of urinary diversion have evolved from simply diverting the urine through a conduit to orthotopic reconstruction, which provides a safe and continent means to store and eliminate urine with efforts to provide an improved quality of life. We address meaningful points that may help optimize clinical results in patients with an orthotopic bladder substitute. The review involved an objective evaluation of the basic science literature of functional, structural and physiological characteristics of gastrointestinal tissue as a substitute for bladder. Potential problems that may be associated with particular parts of the gut for use in reconstruction are discussed. We also summarize the clinical results and complications of orthotopic reconstruction. In the last 10 years the paradigm for choosing urinary diversion has changed substantially: In 2002 all patients undergoing cystectomy were neobladder candidates. It is critically important to understand the phenomenon of maturation. The motor and pharmacological response of the implanted gut changes dramatically toward that of the bladder. Structural and ultrastructural changes in the ileal mucosa lead to a primitive epithelium similar to urothelium. The need for reflux prevention is not the same as in ureterosigmoidostomy conduit or continent diversion. Reflux prevention in neobladders is even less important than in a normal bladder. When using nonrefluxing techniques, the risk of obstruction is at least twice that after direct anastomosis. Kidney function is not impaired by diversion if stenosis is recognized and managed. Patient health status is more influenced by underlying disease than by diversion. Complications of neobladders are actually similar to or lower than the true rates after conduit formation, in contrast to the popular view that conduits are simple and safe. Some degree of nocturnal leakage is a consistent finding in most reports despite a technically sound operation. The precise pathogenesis of urinary retention requiring clean intermittent catheterization remains uncertain. There are new complications, such as neobladder rupture and mucous tamponade. Orthotopic reconstruction has passed the test of time. In these patients life is similar to that in individuals with a native lower urinary tract. Until a better solution is devised orthotopic bladder reconstruction remains the best option for patients requiring cystectomy.