Predictors of outcome for urethral injection of botulinum toxin to treat detrusor sphincter dyssynergia in men with spinal cord injury.

STUDY DESIGN: This is a retrospective study. OBJECTIVES: The objective of this study was to determine outcome predictors for urethral injection of botulinum toxin to treat detrusor sphincter dyssynergia (DSD) in patients with spinal cord injury. METHODS: Botulinum toxin type A (100 Units Botox, Allergan) was injected into the external urethral sphincter using a transperineal approach under EMG guidance. Treatment was indicated if DSD was found on urodynamic testing with a post-void residual volume (PVR) above 100 ml. Urodynamic tests and cystourethrograms were performed at baseline. Dysuria (scale of 1-5) and PVR (48- h bladder diary) were evaluated at baseline and 1 month. The outcome was deemed excellent when PVR was equal to or <100 ml and 20%, and dysuria rated <3. RESULTS: Seventy-two men with tetraplegia and 27 with paraplegia were included. There were significant reductions in PVR (from 227 to 97 ml and 63% to 27%) and dysuria (from 4.3 to 2.3). Excellent outcomes were found in 48 patients (48%), and the duration of effectiveness was 6.5 months. The need for catheterisation was decreased or eliminated in 18 patients. Vesicoureteral reflux disappeared in some patients. Poor outcome was significantly related to the presence of bladder neck dyssynergia and the absence of detrusor contraction in standard cystometry. Outcome was also related to the severity of DSD, with a strong correlation between PVR before and after injection (r=0.58). Injections were repeated in 36 patients and yielded similar outcomes in most cases (89%). CONCLUSIONS: Detrusor contractions (odds ratio=8.6) and normal bladder neck activity (odds ratio=7.1) are strong predictors of excellent outcome.