Video Urodynamic Predictors of Outcomes After Urethral Sphincter Botulinum Toxin A Injection in Spinal Cord-Injured Patients with Detrusor Sphincter Dyssynergia.

Purpose: Detrusor sphincter dyssynergia (DSD), a common lower urinary tract condition in patients with suprasacral spinal cord injury (SCI), can lead to urological complications and reduced quality of life. Urethral sphincter botulinum toxin A (BoNT-A) injection has been used to promote spontaneous voiding, albeit with limited success. This study aimed to identify predictive factors for treatment success.

Methods

This retrospective analysis included 207 patients (157 males and 50 females) with chronic SCI and varying DSD grades treated with urethral sphincter BoNT-A injection. Each received 100 U of onabotulinumtoxinA via transurethral sphincter injection. The primary outcome was voiding efficiency (VE) and symptom improvement, assessed via global response evaluation 3 months post-treatment. Baseline videourodynamic parameters were used to predict success.

Results

Successful outcomes were observed in 33.8% of patients. These patients were older and had higher voiding pressure, maximum flow rate (Qmax), voided volume, bladder contractility index, and VE, as well as lower post-void residual (PVR) volume and bladder outlet obstruction index. Patients with SCI and DSD grade 1 had the highest success rate (65.7%) compared to those with DSD grade 2 (14.3%) or 3 (7.1%). Patients with DSD grade 3 had the highest failure rate (55.8%). Multivariate analysis showed that higher Qmax and lower PVR significantly predicted success, consistent with lower DSD grades.

Conclusion

Grade 1 DSD, higher Qmax, and lower PVR were associated with higher success after urethral BoNT-A injection, whereas grade 3 DSD predicted failure. Thus, careful patient selection is essential for effective DSD treatment with urethral BoNT-A injection.