The search for the holy grail: The efferent segment in continent cutaneous urinary diversion

Two decades of clinical experience with continent cutaneous urinary diversion have led to a broad consensus on reservoir formation, but not on the selection of efferent and afferent segments. Whereas detubularization and spherical reconfiguration of small and/or large bowel has become the undisputed standard procedure for creation of a low pressure, high capacity urinary reservoir, uretero-intestinal anastomosis and construction of the continence mechanism remain contentious issues. The argument in ureteral implantation is on whether reflux prevention is at all necessary, while the discussion about the ideal efferent limb centers on technical aspects of construction. By far the most popular structure for construction of a continence mechanism is the vermiform appendix, followed by tapered, intussuscepted or transversely retubularized ileum, and full thickness bowel flaps. The ureter is the only non-intestinal tube with practical value. Most techniques are based on the so called Mitrofanoff (flap valve) principle which provides reliable continence in more than 90 % of cases and high patient acceptance. Artificial sphincter systems give disappointing results in the setting of urinary diversion. In the future, the construction of efferent conduits with muscular sphincters by tissue engineering may be possible and is an area of active laboratory research.