Modified ileal conduit stoma: safety of freeing the mesenteric edge of the distal part of ileal conduits.

Objective: An ileal conduit is created in about half of all urinary diversions. Difficulties in constructing an abdominal stoma in morbidly obese patients can be challenging, especially if the patient has a short mesentery. Excessive traction on the mesentery in an attempt to pass the distal segment of ileum through the thick abdominal wall may result in ischemia of the whole segment blood supply. We evaluated the safety of freeing the terminal portion of the conduit from its mesentery to facilitate easy passage of the conduit through the abdominal wall and decrease the incidence of parastomal hernia.

Methods: Five domestic pigs were used for this study. In each subject a 10 cm segment of ileum was isolated to form the ileal loop and bowel continuity was established. A 3 to 4 cm segment of the distal ileal loop was freed from its mesenteric blood supply. This segment of the loop was passed through the appropriate defect in the abdominal wall to the skin and an everted stoma was constructed. Postoperatively the animals were followed for 1 month and then sacrificed. The ileal loop with its mesentery and surrounding skin were harvested en bloc and sent for gross and histological examination.

Results: Mean postoperative time was 30 days (range 29 to 32). No mortality or perioperative complications were recorded. All animals had an uneventful postoperative course until the scheduled time for specimen collection. At harvesting the stoma remained pink in all animals. Gross examination and calibration demonstrated no evidence of narrowing or stenosis. Histological examination revealed no ischemic changes. The mucosa of the entire ileal loop was uniform and healthy.

Conclusions: Freeing the mesenteric edge of the ileal loop is safe. This finding has an important application for allowing easy construction of an ileal loop or continent cutaneous diversion stoma in morbidly obese patients. This finding is also applicable when constructing terminal ileostomy or colostomy stoma in select patients.