Surgical management of congenital urethral sphincter mechanism incompetence in eight female cats and a bitch.

Congenital urethral sphincter mechanism incompetence is a cause of urinary incontinence in female dogs and cats. In some of these animals, urethra hypoplasia is the primary diagnosis, with the urethra being almost absent in some patients. Treatment of this problem can be difficult. This paper describes two techniques for the surgical treatment of eight cats and one dog with severe urethral hypoplasia. In five animals, partial excision of the bladder neck was performed to create a longer "urethra." In the other four, an attempt was made to conserve bladder volume while simultaneously creating a urethra with a bladder neck flap reconstruction technique. One cat was lost to follow-up, but the clinical signs resolved in three cats and the remaining animals improved. Two cats had recurring cystitis, possibly associated with bladder neck diverticula because of uterine horn remnants terminating abnormally in the bladder. The results in this limited series suggest that reconstructive surgery in cases of severe urethral hypoplasia improves continence control.