EVALUATION OF A TRANSPELVIC SLING PROCEDURE WITH AND WITHOUT COLPOSUSPENSION FOR TREATMENT OF FEMALE DOGS WITH REFRACTORY URETHRAL SPHINCTER MECHANISM INCOMPETENCE

Objective - To evaluate a sling procedure using a polyester ribbon pas sed through the obturator foramen, around the urethra, and fixed outsi de the pelvis for the treatment of female dogs with refractory urethra l sphincter mechanism incompetence (USMI). Animals - 26 female dogs wi th USMI that had not improved with medical management. Methods - All d ogs underwent a transpelvic sling procedure, and in 13, with a radiogr aphic diagnosis of a pelvic bladder, additional colposuspension was pe rformed. Multichannel urethral pressure profilometry (UPP) and diuresi s cystourethrometry (UCM) were performed in all dogs before and in sev en dogs 2 to 14 months after surgery. Long-term results of surgery and medical therapy were determined. Results - 13 dogs (50%), 6 of these without additional colposuspension, were continent after surgery and r emained continent during a follow-up period of 12 to 36 months (mean, 19 months). Seven, three of which had colposuspension, had improved ma rkedly. Four of these dogs became continent with additional medical th erapy. Five dogs did not improve, and three of these were eventually e uthanatized. In one dog, the sling was removed after 5 days because of persistent stranguria. Surgery and medical therapy together resulted in continence in 17 dogs (65%) during a follow-up period of 6 to 36 mo nths (mean, 22 months). Postoperative dysuria or stranguria occurred i n six dogs, and four of these underwent a colposuspension procedure. T wo dogs developed a fistula, 2 and 3 years after surgery. Preoperative ly, decreased urethral resistance was suggested by the findings of UPP and UCM in 25 dogs, and an abnormally high compliance was found in 3, detrusor instability in 2, and a low threshold pressure in 1 dog. The re was no apparent correlation between these findings and the outcome of surgery. Urethral closure pressures measured after surgery were sig nificantly increased but were still lower than the normal range in all dogs with persistent or recurrent incontinence. Conclusions - A trans pelvic sling procedure, with or without additional colposuspension, ca n be useful in the management of dogs with refractory urinary incontin ence. The procedure is not beneficial if it does not increase urethral pressure close to, or within, the normal range. (C) Copyright 1998 by The American College of Veterinary Surgeons.