Do repeat intradetrusor botulinum toxin type a injections yield valuable results? Clinical and urodynamic results after five injections in patients with neurogenic detrusor overactivity.

OBJECTIVES: To study repeat intradetrusor botulinum toxin injections for the treatment of neurogenic detrusor overactivity in terms of safety and improvement of continence status and urodynamic parameters.

MATERIAL AND METHODS: This study was based on 20 consecutive patients (13 males, 7 females; median age, 41.1 yr) who received at least five intradetrusor injections of botulinum toxin and who were followed by clinical and urodynamic evaluation after at least four injections. The results of 100 injections and corresponding follow-ups were analyzed and compared with baseline.

RESULTS: No toxin-related side effects were observed after the first or repeat injections. All patients had a baseline urodynamic study and at least four urodynamic studies after botulinum toxin injections. Clinical continence improved significantly after the first injection and then remained constant after repeat injections. The median reflex volume increased significantly from a median of 200 ml at baseline to values between 440 and 500 ml at follow-up studies. The presence of neurogenic detrusor overactivity decreased significantly by 60-75%. Maximum cystometric capacity increased significantly 2.3-fold. Maximum detrusor pressure during cystometry decreased significantly 5.8-fold from a median of 70 cm H(2)O to values of about 20 cm H(2)O. Median compliance at baseline (60 ml/cm H(2)O) did not change significantly.

CONCLUSION: Repeat intradetrusor botulinum toxin A injections are a safe and valuable treatment option for neurogenic detrusor overactivity over a period of several years. The beneficial effect of the toxin on clinical and urodynamic parameters remains constant after repeat injections.