Deschamps JY, Roux FA et al Transobturator vaginal tape for treatment for urinary incontinence in spayed bitches. Journal of the American Animal Hospital Association 2015; 51:85-19
Summarised by Dr H van der Zee BVSc, MMedVet (Surg)Bridge Veterinary Hospital
Why they did it
Acquired urinary incontinence can occur in up to 10% of bitches after sterilisation. Medical treatment can control the symptoms in about 80% of cases, but needs continuous medication and phenylpropanolamine, the most effective, is no longer available. Surgery is an option if medical treatment fails or if continuous medication is a problem.
Previous techniques are quite cumbersome and do not have a higher success rate. Since the 1990s, an intravaginal sling plasty called ‘‘tension-free vaginal tape’’ (TVT) has become the most popular surgical procedure for the treatment of female urinary stress incontinence in humans throughout the world, with a success rate of 92%.
What they did
With this technique a strap of polypropylene mesh is passed over the urethra just proximal to its opening. Although there are differences in the reasons for incontinence between humans and dogs, the principal could be effective in dogs. A variation of the original TVT technique, the ‘‘trans-obturator vaginal tape inside-out’’ (TVT-O) technique, has been shown to be safe and effective in the female dog and an initial report showed success in 6/7 dogs.
Due to the cost of the original human products, a variant of the TVT – O technique was used with a nylon tape. The procedure was done on 12 female dogs, with a median age of 5.5 years, which became incontinent after sterilisation. The technique is described in the article. After an episiotomy, one end of the nylon tape is passed through an incision in the vagina, just proximal to the opening of the urethra. The tape is passed through the obturator foramen and out through the skin on the midline below the pubis.
The other end is passed around the contra-lateral side. The ends of the tape are pulled through the skin until the middle section lay against the urethra with only mild pressure. The ends of the tape were then knotted underneath the skin. Routine closure of all incisions were made. Post-operative pain relief was provided and the dogs were discharged as soon as they could urinate with ease.
What they found
Post-operative dysuria was present in seven dogs, with three dogs needing temporary catheterisation. In one dog there was severe dysuria and the knot had to be cut to relieve tension. This dog remained greatly improved despite the knot being cut. At two weeks post-operatively, 11 of 12 dogs did not show any episodes of leakage.
At the second evaluation with a median follow-up time of 21 months, three patients (25%) were ”cured”, six patients (50%) were greatly improved and three (25%) patients were improved according to the scoring system used. According to the owners, three were cured and all the others were greatly improved.
Two dogs had a second surgery performed due to unsatisfactory results and improved significantly thereafter. Two dogs developed sinus tracts 28 and 32 months of the surgery. The implants were removed in these cases. At the last evaluation with a median follow-up period of 52 months, the results stayed the same.
Take home message
The TVT-O technique is technically easier and can get the same or better results than current surgical techniques to treat post-spay incontinence. Although the technique used here was more economical than the original technique described in humans, it was associated with post-operative dysuria, delayed sinus tract formation (from nylon tape) and partial recurrence of urine leakage. Using polypropylene tape is probably safer, as it has been shown to be well tolerated in dogs.