Cryosurgery of the ureter in dogs.

The effect of cryosurgery on the ureter has been studied in dogs. A single 1- or 2-min cryosurgical exposure produced stricture in two of eight animals. A tumoricidal cryosrugical dose consisting of three, 2-min exposures caused stricture in six of eight dogs. Histopathologic examination of the ureter after repetitive cryosurgery showed progressive, persistent loss of smooth muscle, fibrosis of the lamina propria, and early loss with subsequent regeneration of the transitional epithelium. Although there was no loss of ureteral integrity, the possibility of permanent ureteral damage should be considered with the use of cryosurgery.