Effect of botulinum a toxin in the treatment of voiding dysfunction due to detrusor underactivity.

OBJECTIVES: To investigate the effects of botulinum A toxin in treating patients with voiding dysfunction due to detrusor underactivity.

METHODS: Twenty patients with chronic urinary retention (n = 13) or severe dysuria (n = 7) received 50 U of botulinum A toxin by urethral injection. The clinical effects, obstructive symptom score, quality-of-life index, and urodynamics were compared at baseline and after treatment.

RESULTS: Of the 4 males and 16 females (age range 14 to 86 years) with voiding dysfunction (cauda equina lesion in 5, dysfunctional voiding in 5, peripheral neuropathy in 6, and detrusor failure of unknown origin in 4), 18 (90%) were treated satisfactorily. Among these patients, the mean quality-of-life score decreased significantly from 5.68 +/- 0.67 to 1.16 +/- 1.61. The median voiding pressure (56.5 +/- 41.2 versus 39.0 +/- 38.4 cm H(2)O) decreased significantly, as did the maximal urethral closure pressure (65.5 +/- 38.1 versus 50 +/- 32.1 cm H(2)O) and residual urine volume (300 +/- 189.1 versus 50 +/- 153.6 mL) at 2 weeks after treatment and remained stationary for 3 months. The subjective maximal effect was achieved within 1 to 2 weeks. In 7 patients, the indwelling catheters were removed, and in 4 patients who performed clean intermittent self-catheterization, the frequency decreased or it was discontinued. The other 7 patients with difficult urination had significant improvement in the obstructive symptom score (18 +/- 3.3 versus 7 +/- 4.5, P = 0.000).

CONCLUSIONS: Botulinum A toxin at a dose of 50 U was effective in reducing urethral sphincter resistance among our patients with detrusor underactivity and difficult urination.