Seromuscular grafts for bladder reconstruction: extra-luminal demucosalisation of the bowel.

Objective: To develop a robust sterile, fully demucosalized and vascularized seromuscular patch for use as an adjunct to novel bioengineering techniques aimed at augmenting, reconstructing, or replacing the bladder because of endstage disease. To eliminate deep colonic epithelial crypts to prevent the possibility of colonocyte regrowth. To maintain sterility by excluding the possibility of contamination from the bowel contents.

Methods: Pilot studies were performed on euthanized pigs to optimize the technique, with tissue samples examined by immunohistochemistry. In vivo, vascularized seromuscular colonic flaps were created from the bowel exterior in 7 large white hybrid pigs. The dissection was facilitated by placing an inflated Foley catheter within the colonic lumen. The seromuscular ends were approximated with 5/0 Vicryl sutures and excess mucosa intussuscepted within the lumen. Demucosalized flaps were used to augment the bladder by composite cystoplasty and were examined immunohistochemically at 3 months.

Results: Pilot studies showed that the technique was successful in creating seromuscular segments with no epithelial remnants. When applied surgically, the seromuscular flaps survived and showed no evidence of colonocyte regrowth at 3 months.

Conclusion: Extraluminal dissection creates robust seromuscular flaps and prevents both regrowth by colonic epithelial cells and contamination of the tissue by exposure to the bowel contents. This technique should find application in a range of bladder reconstruction techniques, including composite cystoplasty and autoaugmentation.