Experience with 100 cases treated with botulinum-A toxin injections in the detrusor muscle for idiopathic overactive bladder syndrome refractory to anticholinergics

Purpose: In this prospective, nonrandomized, ongoing study we evaluated the efficacy and safety of botulinum-A toxin injections in the detrusor muscle to treat patients with idiopathic overactive bladder resistant to conventional treatment, such as anticholinergic drugs. Materials and Methods: A total of 23 men and 77 women with a mean age of 63 years (range 24 to 89) with nonneurogenic overactive bladder, including urgency-frequency syndrome, and incontinence despite the administration of maximal doses of anticholinergics were consecutively treated with injections of 100 U botulinum-A toxin in the detrusor muscle at 30 sites under cystoscopic guidance. Micturition diary, full urodynamics, neurological status and urine probes were performed in all participants before treatment. Bladder biopsies were done only in cases of suspected bladder fibrosis or unclear findings. Special attention was given to reflex volume, maximal bladder capacity, detrusor compliance, post-void residual urine, urgency and frequency/nocturia. Clinical, urodynamic and quality of life assessments were performed at baseline, and 4, 12 and 36 weeks after botulinum-A toxin treatment. Results: Overall after 4 and 12 weeks 88% of our patients showed significant improvement in bladder function in regard to subjective symptoms, quality of life and urodynamic parameters (p < 0.001). Urgency disappeared in 82% of the patients and incontinence resolved in 86% within 1 to 2 weeks after botulinum-A toxin injections. Mean frequency decreased from 14 to 7 micturitions daily (- 50%) and nocturia decreased from 4 to 1. 5 micturitions. Mean maximal bladder capacity increased 56% from 246 to 381 ml, mean detrusor compliance increased from 24 to 41 ml/cm H2O and pretreatment detrusor instability (mean reflex volume 169 ml) resolved in 74% of patients. Mean volume at first desire to void increased from 126 to 212 ml and mean urge volume increased from 214 to 309 ml. There were no severe side effects except temporary urine retention in 4 cases. Only in 8 patients was the clinical benefit poor and analysis revealed preoperative low detrusor compliance. Mean efficacy duration +/- SD was at least approximately 6 +/- 2 months and then symptoms began to increase. Conclusions: Our results show that intradetrusor botulinum-A toxin injections may be an efficient and safe treatment option in patients with severe overactive bladder resistant to all conventional treatments.