Department of Neurology and Psychiatry, 'Sapienza', University of Rome, Italy.Viale dell'Universitá 30, Rome, and IRCCS Neuromed, Rome; Department of Urology and Andrology, Ospedale S. Maria della Misericordia, S. Andrea delle Fratte, University of Perugia, Perugia; Department of Neurology, Ospedale S. Maria della Misericordia, S.Andrea delle Fratte, University of Perugia, Perugia.
Although botulinum toxin (BoNT/A) injected into the detrusor muscle improves overactive bladder symptoms in patients with neurogenic detrusor overactivity, how it does so remains unclear. In this study, we investigated whether BoNT/A improves detrusor overactivity by modulating bladder afferent activity.
To do so, during urodynamic assessment, we tested the soleus muscle Hoffmann (H) reflex during bladder filling before and after intradetrusor BoNT/A in patients with Parkinson's disease (PD) and in patients with complete chronic spinal cord lesion (SCI) and detrusor overactivity refractory to conventional therapy. Healthy subjects underwent H reflex studies during urodynamic assessment and acted as controls.
Our findings show that BoNT/A injected into the detrusor muscle effectively reduces clinical overactive bladder symptoms in patients with PD and SCI. In healthy subjects and patients with PD, bladder filling [at maximum cystometric capacity, (MCC)] significantly decreased the H reflex size, whereas in patients with SCI, it slightly facilitated the H reflex size. At MCC, in patients with PD, BoNT/A significantly reduced the expected H reflex inhibition, whereas in those with SCI, BoNT/A turned the H reflex facilitation at maximum bladder filling into a slight inhibition.
These findings show that BoNT/A injected into the detrusor muscle in patients with PD and SCI modulates bladder afferent activity. Modulation of bladder afferents possibly explains why BoNT/A improves detrusor overactivity.
Conte A, Giannantoni A, Proietti S, Giovannozzi S, Fabbrini G, Rossi A, Porena M, Berardelli A. Are you the author?
Reference: Eur J Neurol. 2011 Dec 28. Epub ahead of print.