An experimental study of colonic mucosal graft for urethral reconstruction.

Objective: To investigate the possibility of urethral reconstruction with a free colonic mucosal graft.
Methods: Ten female dogs underwent a procedure in which the urethral mucosa was totally removed and replaced with a free graft of colic mucosa. A urodynamic study was performed before the operation and sacrifice. The dogs were sacrificed 8 to 16 weeks after the operation for histological examination of the urethra.
Results: Urethral stricture developed in 1 dog. The results of urody namic studies showed that the difference in maximum urethral pressure between pre-operation and pre-sacrifice in the remaining 9 dogs was not of significance (P > 0.05). Histological examination revealed that the colonic free mucosa survived inside the urethral lumen of the 9 dogs. Plicae surface and unilaminar cylindric epithelium of the colonic mucosa was observed in dogs sacrificed 8 weeks after the operation. Plicae surface and unilaminar cylindric epithelium of the colonic mucosa was not observed and metaplastic transitional epithelium covered a large proportion of the urethral mucosa in dogs sacrificed 12 weeks after the operation.
Conclusions: Urethral mucosa can be replaced by colonic mucosa without damaging the continence mechanism in female dogs. This technique is useful when local or preputial skin and buccal or bladder mucosa are not available.