The Use of Botulinum Toxin A Injection for the Management of External Sphincter Dyssynergia in Neurologically Normal Children

Abstract

Botulinum toxin A has previously been used for neurogenic and nonneurogenic urgency and urge incontinence. We evaluated the effects of sphincteric botulinum toxin A injection in a series of neurologically normal children with evidence of external sphincter dyssynergia with various voiding problems documented by abnormal voiding electromyography as well as voiding cystourethrography to assess its effectiveness for eliminating post-void residual urine. We retrospectively reviewed the charts of 16 dysfunctional voiders who underwent botulinum toxin A injection to the external sphincter between 2002 and 2006, including 1 to 3 injections in 14, 1 and 1, respectively. Of 19 injections 17 were performed with 300 U to the sphincter, while 2 of 19 were done with 200 U. Two patients also received 100 U injected into the detrusor. Mean patient age at surgery was 9.0 years (range 6 to 16). Preoperative clinical data were recorded, including medications, electromyography, uroflowmetry with post-void residual urine, ultrasound and voiding cystourethrography. Before botulinum toxin A injection medical therapies had failed in all patients, including alpha-blockers in 100%, biofeedback in 100%, oxybutynin in 33% and tricyclics in 3 (20%). One patient was on intermittent catheterization. All patients were refractory to bowel regimens and timed voiding. Postoperative parameters consisted of medications, symptoms and post-void residual urine. In the 3 males the resolution of epididymitis symptoms and prevention of recurrence were evidence of success. Before treatment patients experienced symptoms of urge incontinence (14 of 16), recurrent urinary tract infections (66%), voiding postponement (45%) and epididymitis (3 of 16). All patients had external sphincter dyssynergia, as documented by preoperative electromyography or voiding cystourethrography. Average preoperative post-void residual urine was 107 cc (range 49 to 218). Two patients who underwent preoperative voiding cystourethrography had unilateral grade 1 reflux. Of the 16 children 12 (75%) were dry at the first postoperative visit. The remaining 2 patients had decreased enuresis and 13 of 16 were dry at the second postoperative visit. The last patient became dry after treatment for attention deficit disorder was initiated. Average initial postoperative post-void residual urine volume was 43 cc (range 0 to 141) and the average best postoperative visit post-void residual urine was 8 cc (range 0 to 26). Uroflow data revealed no difference in uroflow before or after injections. Neuropsychiatric problems were present in 9 of the 16 patients, including depression in 4, anxiety in 3 and attention deficit disorder in 2. Before our study in the pediatric literature doses between 50 and 100 U were used. We used a significantly higher dose with increased efficacy and no increased morbidity. Endoscopic botulinum toxin A injection of the external sphincter appears to be a safe and efficacious way to treat refractory nonneurogenic voiding dysfunction in children with external sphincter dyssynergia. Long-term followup is necessary and repeat endoscopic injections may be required in select patients.