Total replacement of urethral mucosa with oral mucosa in dogs

If the urethral mucosa is replaced by another mucosa, urethral recurrence might decrease in patients who undergo neobladder construction for bladder cancer. We determined whether such replacement is possible.

Six dogs underwent an operation consisting of a longitudinal urethral incision at its full length and immediate closure. In 6 other dogs, after the urethral mucosa was totally removed, a tubularized sublingual mucosa was closely set inside the urethral lumen. Postoperatively, the urinary stream and external meatus were observed every day. To measure urine leakage, a 10-minute pad test was performed once a month. All dogs were sacrificed 3 to 12 weeks after the operation for histological examination of the urethra. The excised urethras were examined with a 12F catheter for urethral patency.

All dogs were continent postoperatively. The results of the 10-minute pad test showed no significant difference in the weight increase of the pad among the control, sham-operated and mucosa-replaced dogs. Urethral stricture developed in 1 mucosa-replaced dog. Histological examination revealed that all of the grafted oral mucosa survived in the urethra.

These results indicate that the urethral mucosa can be replaced by oral mucosa without damaging the continence mechanism in female dogs.