A new technique for ureteral reconstruction using a colonic mucosa graft in a beagle model.

Objective: To investigate the feasibility of using a colonic mucosa graft (CMG) for ureteral reconstruction and assess histological changes following the engrafted CMG in Beagles. Methods: Nine male Beagle dogs were randomly assigned to groups I, II, and III (n=3). Resection of half of the ureteral wall caused a ventral ureteral defect. Ureteral defects with lengths of 3 cm, 5 cm, and 10 cm were created in these groups, respectively. The CMG was harvested and used to repair the ureteral defects in an onlay fashion. After functional evaluation of the reconstructed ureter using CT urography at 3 months, 6 months, and 12 months postoperatively, one Beagle from each group was euthanized using air embolization. Ureteral diameter measurements and the CMG shrinkage rate calculations were performed. Histological analysis was conducted to assess changes in the engrafted CMG. Results: All animals had no postoperative complications. CT urography showed normal renal function and a wide caliber ureter with no stricture or leakage. The ureteral diameter reconstructed by the CMG was larger than that of the proximal or distal normal ureter (p<0.05). The mean shrinkage rate of the CMG ranged from 11% to 14%. From 3 months to 12 months postoperatively, the colonic mucosal epithelium gradually underwent metaplasia into urothelium, and smooth muscle and neovascularization gradually developed beneath the mucosa. Conclusion: The novel technique of using a CMG for ureteral reconstruction is feasible. The CMG has the advantages of low shrinkage rate and minimal donor site complications. It is an ideal material for treating long ureteral strictures.