The Efficacy of Botulinum Toxin in Spastic Neuropathic Bladder

Neurogenic detrusor overactivity (NDO) can result in lower and upper urinary tract complications and eventually even in end-stage kidney failure. Since the driving force of this clinical cascade is high bladder pressure, controlling intravesical pressure in NDO patients improves both quality of life and life-expectancy in these patients. Botulinum toxin A (BTX-A) has proven its efficacy in reducing intravesical pressure and in reducing incontinence episodes. BTX-A also improves quality of life in patients with NDO. Both onabotulinumtoxinA (Botox®, Allergan, Irvine, USA) and abobotulinumtoxinA (Dysport®, Ipsen, Paris, France) have a level A recommendation for NDO-treatment. The recommended dose for intradetrusor injections in NDO patients is 200 U of onabotulinumtoxinA or 500 U of abobotulinumtoxinA. The drug is generally administered extratrigonal in the detrusor muscle, via cystoscopic guided injection at 20 sites in 1 mL injections. Intradetrusor BTX-A injections are safe, with mostly local complications such as urinary tract infection and high post-void residual or retention. The effect of the toxin lasts for approximately 9 months. Repeat injections can be performed without loss of efficacy. Different injection techniques, novel ways of BTX-A administration, eliminating the need for injection or new BTX-A types with better/longer response rates could change the field in the future.

Botulinum toxins are neurotoxins produced by the facultative anaerobe Clostridium botulinum that block the release of acetylcholine into the synaptic gap of the neuromuscular junction. Their injection near the nerves that supply the target organ selectively and temporarily paralyzes the organ. In particular, the subtype botulinum-A toxin is widely used in neurology to release spastic dystonia in adults and children . In urologic disorders, botulinum-A toxin reliably diminishes external sphincter or detrusor overactivity.