Transobturator Vaginal Tape Inside Out for Treatment of Urethral Sphincter Mechanism Incompetence: Preliminary Results in 7 Female Dogs

Objectives: To evaluate the clinical efficacy of the transobturator vaginal tape inside-out (TVT-O) in incontinent female dogs affected with urethral sphincter mechanism incompetence (USMI) and to determine its urodynamic and morphologic effects. Study Design: Case series. Animals: Incontinent spayed female dogs (n=7). Methods: TVT-O tape was inserted in 7 incontinent female dogs diagnosed with USMI. Urethral pressure profilometry (UPP) and vaginourethrograms were performed preoperatively, and 1 and 3 months postoperatively. Clinical efficacy of the technique was evaluated and complications reported. Follow-up information was evaluated by a telephone questionnaire. Results: All dogs were continent immediately after the procedure. Incontinence recurred 2 months after surgery in 1 dog and was treated by phenylpropanolamine administration. At mean follow-up time of 11.3 months, 6 of 7 dogs were continent. An iatrogenic urethral tear occurred intraoperatively in 1 dog. No postoperative complications were encountered. The postoperative UPPs showed significantly increased maximal urethral closure pressure and integrated pressure. Postoperative vaginourethrograms were unremarkable. The surgical procedure did not modify the location of the urinary bladder neck in dogs with a ‘‘pelvic urinary bladder’’ preoperatively. Conclusions: TVT-O was efficient in maintaining short term continence in 6 of 7 dogs affected with USMI. Urethral sphincter mechanism incompetence (USMI) is the most common cause of acquired urinary incontinence in female dogs.1 It mainly affects mostly middle-aged, large breed, spayed female dogs.2,3 Clinical signs such as urine leakage during sleep or periods of excitement may develop a few weeks to several years after spaying, most commonly after 2–3 years.2,4,5 The cause is multifactorial with numerous factors identified or suspected to contribute to incontinence, including urethral tone and length, position of the urinary bladder neck, breed, size, neutering, obesity, age, and tail docking.2,3,6–16 The initial treatment of USMI is usually medical. Alpha-adrenergic drugs (eg, phenylpropanolamine [PPA]) are commonly used17–19 and the reported success rate ranges from 85–97% continence.19–22 Short-acting estrogens (estriol