Outcomes of Intradetrusor OnabotulinumtoxinA Injection in Adults with Congenital Spinal Dysraphism at a Tertiary Transitional Urology Clinic

Introduction: Published data regarding intradetrusor injection of onabotulinumtoxinA in adults with congenital spinal dysraphism are scarce. We retrospectively investigated the outcomes of intradetrusor injection of onabotulinumtoxinA in this setting. Methods: Billing codes were used to identify 149 patients who underwent onabotulinumtoxinA injection between 2012 and 2016 at our tertiary transitional urology clinic. Charts were then reviewed to identify patients with congenital spinal dysraphism. Results: A total of 18 patients with a mean age of 20.76 (±3.03) years at the time of first onabotulinumtoxinA injection were identified. All patients had urinary incontinence. Urinary incontinence improved by injection of 200 or 300 U onabotulinumtoxinA in 81.2% of patients and 63.6% of them became dry (p=0.023). Mean glomerular filtration rate before and 13.3 (±9) months after treatment was 100.2 (±17.2) and 120.1 (±16.6) ml/minute/1.73 m², respectively (p=0.41). Baseline hydronephrosis improved in 3 of 4 patients. Repeat urodynamic study after injection was done in 11 patients who did not have clinical improvement or who had loss of bladder compliance at baseline (29.3 vs 67.2 ml/cm H₂O). Mean maximum cystometric capacity before and after injection was 310.1 and 380.2 ml, respectively (p=0.045). Mean bladder compliance before and after treatment was 29.2 and 28.7 ml/cm H₂O, respectively (p=0.48) in this high risk group. Conclusions: Intradetrusor onabotulinumtoxinA injection may improve refractory urinary incontinence in selected adults with spinal dysraphism. However, despite improvement in maximum cystometric capacity, bladder compliance does not improve after therapy in patients who had loss of compliance at baseline.