BERKELEY, CA (UroToday Inc.) - There has been recent enthusiasm for the use of botulinum-A toxin (BTX-A) in the treatment of voiding dysfunction secondary to detrusor overactivity. Werner and colleagues from Lucerne and Zurich, Switzerland performed a nonrandomized prospective study in the treatment of incontinence associated with non-neurogenic detrusor overactivity. Their findings were published in the May 2005 edition of the American Journal of Obstetrics and Gynecology.

They studied 26 women who had urge incontinence with urodynamically proven detrusor overactivity that was refractory to prior medication. None of these women suffered from a neurologic disease or injury. The women received 100 units of BTX-A diluted in 30 ml of normal saline. Equal doses (1 ml) of the dilute BTX-A solution were injected, under cystoscopic guidance, at 30 different locations into the bladder muscle. Patients were followed clinically and urodynamically at 4, 12, and 36 weeks after treatment. The primary outcomes were safety, maximum cystometric bladder capacity (MCBC), volume at first and strong desire to void, daytime frequency, and nocturia. Secondary outcomes included subjective improvement, post void residual, and quality of life assessment using the King's Health Questionnaire. Failures were defined as no urodynamic or subjective change after treatment. These patients were offered a second treatment if they initially failed treatment or had a recurrent symptoms after an initial improvement.

The mean age of the 26 patients was 66 years (range, 48-84 years). At baseline, the mean MCBC was 216 ml, with 50% (13/26) having a MCBC less than 200 ml. The mean volume at the first desire to void was 116.8 ml, mean volume at strong desire to void 176.6 ml, and PVR 18.0 ml. Mean daytime frequency and nocturia episodes were 11.7 and 2.6, respectively. Baseline quality of life assessments revealed that in 9 of 10 urge-related items, patients recorded the highest impact category. The only category which was not highly impacted was effect on sleep.

BTX-A was administered, without injection related complications, to all patients. There was follow up information at 4 weeks for all subjects, but only on 20 patients at 12 weeks, and 5 patients at 36 weeks. At four weeks, there was a significant increase in MCBC, improvement in bladder compliance, and increase in PVR, daytime frequency and nocturia. In the 5 patients who were followed out 36 weeks, the same improvements in MCBC and bladder compliance were present. There were no detrusor contractions seen in 54% of patients at 4 weeks.

After 4 weeks, 59% of patients were subjectively free of urge incontinence episodes, and 80% (16/20) were free after 12 weeks, while 20% (1/5) were free at 36 weeks. QoL assessment at 4 and 12 weeks revealed significant improvements in urge- related items.

There were no cases of acute urinary retention, 2 patients had no benefit and dropped out after the first follow-up visit, 2 patients were re-injected after diminishing effects of initial injections. 24/26 patients who had a successful treatment would be willing to undergo a repeat BTX-A injection if the efficacy were to diminish.

The authors conclude that intra-detrusor injections of 100 units of BTX-A appear to be a safe and efficacious in the management refractory non-neurogenic detrusor overactivity associated with urge incontinence. They also agree that larger studies are needed to determine its exact role. This adds to the growing body of literature implicating BTX-A as a useful tool in the treatment of lower urinary tract dysfunction.

Am J Obstet Gynceol 2005; 192: 1735-40