External Urethral Sphincter Botulinum Toxin Injection to Treat Pseudodysynergia in Patients With Cerebral Palsy

Abstract

To evaluate urinary outcomes following cystoscopic external urinary sphincter onabotulinumtoxinA (BTX) injections in patients with CP. Adults with cerebral palsy (CP) can suffer from bladder outlet obstruction and urinary retention due to a spastic external urethral sphincter ("pseudodysynergia"). We have used BTX injections into the sphincter to relieve the obstruction and allow patients to maintain spontaneous voiding rather than intermittent catheterization. Patients were included in this retrospective cohort study if they had a diagnosis of CP, were at least 18 years of age, and underwent a urethral external sphincter BTX injection between 2016-2023. The procedure included 100u or 200u of BTX mixed in 4cc of saline. Primary outcomes were subjective, patient or caregiver reported changes in retention, lower urinary tract symptoms (LUTS), frequency of recurrent urinary tract infections (UTIs), and hydronephrosis or bladder stones/debris on ultrasound. 50 patients were included; the majority were male (60%), lived at home with assistance (58%), and had a Gross Motor Function Classification System level of V (50%; i.e., severe CP). The most common indications for BTX were retention (96%), LUTS (48%), hydronephrosis (18%), and recurrent UTIs (22%). Post-BTX improvement was seen in 67% of those with LUTS, 65% with retention, 67% with hydronephrosis, and 73% with recurrent UTIs. Most patients underwent repeat injections (60%). There were no significant complications associated with injections. External urethral sphincter BTX is a safe, effective option for treating pseudodysynergia in adults with CP.