Botulinum toxin: a new dimension in the treatment of lower urinary tract dysfunction

[Botulinum toxin for the treatment of neurogenic detrusor hyperactivity. Consensus paper on use for neurogenic bladder dysfunction]

Due to elevated intravesical storage pressures, neurogenic bladder dysfunction carries a high risk of renal damage. Thus, the goals of neurourologic treatment are reduction of intravesical storage pressure and intermittent bladder emptying in order to protect renal function and to achieve continence. If anticholinergic medication is either ineffective or intolerable, several open and controlled studies showed that the injection of botulinum toxin A into the detrusor muscle is a minimally invasive, safe, and effective treatment option. These studies demonstrated an effective reduction of storage pressures and a significant increase in bladder capacity. The effect has been shown to last up to a year. As this treatment is not approved by European administrations, botulinum toxin A treatment fulfills all criteria for "justified off-label use." The reduction of intravesical storage pressure leads to an improvement of life expectancy due to upper urinary tract protection. Furthermore, quality of life can be improved by low incidence of urinary tract infections, secure continence, and physiologic catheterization intervals.

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 H(2)O 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.

Intravesical injection of botulinum toxin for the treatment of overactive bladder

PURPOSE OF REVIEW

In recent years, botulinum toxin has been investigated for the treatment of various types of lower urinary tract dysfunctions. This review discusses recently published data related to the therapeutic applications of botulinum toxin in overactive bladder as well as the effects of repeated doses, cross-reactivity between different serotypes, and side effects of the toxin injection into the detrusor muscle.

RECENT FINDINGS

Botulinum toxin A has been employed initially in the treatment of neurogenic detrusor overactivity in spinal cord injured patients. Since then, several reports, including a large multicenter study, have confirmed the therapeutic effects of this neurotoxin. The application of botulinum toxin A was extended to the treatment of idiopathic detrusor overactivity and similar results were obtained. Repeated injections of botulinum toxin A had the same sustained benefit. Recently, botulinum toxin B was investigated for the treatments of both neurogenic and idiopathic detrusor overactivity as well as for the management of botulinum toxin A resistant cases.

SUMMARY

Although intradetrusal injection of botulinum toxin is not yet an approved treatment for overactive bladder, available data suggest that botulinum toxin can be a therapeutic option in patients with neurogenic and nonneurogenic detrusor overactivity who are refractory to anticholinergic medications. There is a need, however, for further investigation to determine the optimal conditions for these applications. A randomized, double-blinded, placebo-controlled trial to evaluate the therapeutic effects of botulinum toxin is under way.