Urodynamic evidence of effectiveness of botulinum A toxin injection in treatment of detrusor overactivity refractory to anticholinergic agents.

OBJECTIVES: To investigate the urodynamic changes after detrusor injection of botulinum A toxin in patients with detrusor overactivity refractory to treatment with anticholinergic agents.

METHODS: Thirty patients with detrusor overactivity refractory to anticholinergic agents were treated with detrusor injection of botulinum A toxin (Botox) 200 U at 40 sites. Urodynamic parameters and symptom scores were assessed at baseline and 2 weeks and 3 months after the injections. Patients' responses were classified as excellent, improved, or failed.

RESULTS: The 12 female and 18 male patients were aged 7 to 83 years (mean 67 +/- 17). Of the 30 patients, 12 had neurogenic detrusor overactivity, 8 had idiopathic detrusor overactivity, and 10 had previous bladder outlet obstruction or had undergone previous transurethral prostatectomy. After detrusor botulinum A toxin injection, 8 patients regained urinary continence (26.7%), 14 patients had improvement in frequency, urgency, and incontinence (46.7%), and treatment failed 8 patients (26.7%). The total success rate was 73.3%. Four patients experienced transient urinary retention and six had difficulty urinating after treatment. The urodynamic results showed increased cystometric capacity, decreased voiding pressure, increased postvoid residual urinary volume, decreased voiding efficiency, and increased bladder neck opening time at 2 weeks. The voiding pressure remained low and bladder neck opening time remained increased at 3 months, although the postvoid residual volume and voiding efficiency had returned to baseline levels. The therapeutic effects lasted for 3 to 9 months (mean 5.3).

CONCLUSIONS: Detrusor injection of 200 U of botulinum A toxin is effective in the treatment of detrusor overactivity that is refractory to anticholinergic agents. Patients with detrusor overactivity and inadequate contractility should be carefully selected for this procedure because the postvoid residual urine volume may increase after treatment.