Botulinum toxin for voiding dysfunction progresses

August 15, 2005

San Antonio--A number of new techniques for management of urinary incontinence and other female urologic problems are affording promising results, according to studies presented at the AUA annual meeting. However, urologists wondering about integrating those approaches into their clinical practices need to be very careful in considering the data, paying special attention to issues of durability and comparisons with existing treatment approaches, said Shlomo Raz, MD, professor of urology at UCLA School of Medicine.

San Antonio-A number of new techniques for management of urinary incontinence and other female urologic problems are affording promising results, according to studies presented at the AUA annual meeting. However, urologists wondering about integrating those approaches into their clinical practices need to be very careful in considering the data, paying special attention to issues of durability and comparisons with existing treatment approaches, said Shlomo Raz, MD, professor of urology at UCLA School of Medicine.

Botulinum toxin A (Botox) is coming of age as an agent in managing neurogenic and non-neurogenic detrusor overactivity.

A Swiss study of patients who had failed anticholinergic therapy showed excellent symptomatic and urodynamic responses, with duration of effect extending approximately 9 months. A similar study from Germany reported duration of effect reaching 5 months. Questions remain about this treatment approach, including which patients to inject, where and how much material to inject, how long the treatment lasts, and how many re-treatments are necessary, efficacious, and safe. Ongoing placebo-controlled trials should provide answers within a few years.

"There have not been good prospective, randomized studies evaluating its efficacy, and the available data are all short-term with maximum follow-up of 9 months. We know the effect dissipates after 6 to 8 months, but we don't know if reinjection will be effective, nor do we know what is the best dosage and method of administration. Perhaps lower doses than have been used would be just as beneficial, and we don't know if the toxin should be injected into the bladder wall or trigone," he said.

In the meantime, Dr. Raz believes botulinum toxin A warrants further study and can be offered judiciously to selected patients with a careful informed consent discussion. Patients need to understand its use in voiding dysfunction is off-label, very expensive, not covered by insurance, and provides only temporary improvement.

"Make sure you provide patients with appropriate expectations so you do not present botulinum toxin as a panacea," Dr. Raz advised.

Cystocele repair using an adjuvant porcine skin collagen graft (Pelvicol, Bard Urological, Covington, GA) appeared feasible in a randomized trial, although results were not significantly different from a group not receiving the graft at 6.5-month follow-up.

This report is a reminder that there is no proof regarding the long-term durability of repair procedures involving use of organic materials, including both cadaveric fascia and xenografts, Dr. Raz said.

"It is my belief that all organic materials are eventually reabsorbed and their remodeling does not lead to fascia
reconstruction.

"Consistent with that idea are our own disappointing results showing pubovaginal sling procedures performed with cadaveric fascia had a 30% failure rate after less than 1 year of follow-up," he pointed out.

As an alternative, Dr. Raz favors use of nonabsorbable polypropylene mesh, which is less expensive and which has proven durability and safety.

A technique for posterior repair uses polypropylene mesh in a T-shaped graft that approximates the sacrouterine ligaments. The graft is tunneled along the posterior vaginal wall and is attached to the perineum, providing a complete repair of the posterior vaginal wall and apex of the vagina.

Dr. Raz and his colleagues at UCLA developed this new procedure in which the nonabsorbable polypropylene mesh is shaped into the form of a "T" consisting of two transverse arms measuring 4X1 cm and a 3X6-cm vertical segment. The transverse portions recreate the sacrouterine ligaments in support of the vaginal cuff, and the vertical segment is used in repair of the rectocele and for support of the perineal musculature.

"Existing surgical procedures for vault prolapse do not repair the pelvic floor descent that is present in most patients. This is the first procedure to address that problem. Our results so far are encouraging, but more follow-up is needed as we have only reported 1-year results from 50 patients," he cautioned.