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)