OnabotulinumA toxin injections: A novel option for management of refractory nocturnal enuresis

Introduction: While not entirely understood, nocturnal enuresis (NE) has been considered pathophysiologically distinct from other non-neurogenic voiding disorders. We believe that a significant component of the pathology is due to bladder overactivity. Intravesical Onabotulinumtoxin A (OBTA) injections are utilized in overactive bladder management. We hypothesized that OBTA injections would be efficacious for NE management in pediatric patients with symptoms refractory to conventional therapies.

Materials and methods: A retrospective cohort analysis of patients <18-years-old with primary NE who underwent OBTA injections was performed. Injections were performed by a single surgeon at a single tertiary referral center per standardized protocol. Treatment response was defined as no improvement, greater than 50 % improvement in nightly accidents, or complete resolution of accidents. The primary outcome was treatment success, defined as greater than 50 % improvement in nightly accidents or complete resolution. Secondary outcomes included treatment response duration and complication data. Descriptive and bivariate statistics were performed as indicated. A Kaplan Meier analysis was performed to assess failure free survival following OBTA injection.

Results: Fifty patients met inclusion criteria for this analysis. All patients had trialed at least one lifestyle modification, a bowel regimen, and at least two medications with symptom persistence. The median post-procedure follow-up time was 9.5 months (range 2-82). Improvement in incontinence symptoms compared to pre-operative baseline was seen in 94.0 % of patients, with 58.0 % demonstrating complete resolution of incontinence through most recent follow up. There was no difference in improvement rates or resolution rates in male vs female gender. The median failure free survival identified on Kaplan Meier analysis was 12.5 months (Figure 1) Minor post-operative complications (4 urinary tract infections; 1 retentive episode necessitating catheterization) were identified in five patients. There were no major post-operative complications.

Discussion: Efficacy of OBTA injections was high, with treatment success demonstrated in 94 % of patients and failure free survival of 12.5 months. This procedure also demonstrated a favorable safety profile, with few minor post-operative complications identified. These results indicate that this procedure may be a beneficial therapeutic option for patients with NE refractory to multiple lines of conventional therapy. This study is limited by its retrospective design with short median follow up and potential for recall bias. It is strengthened by its large sample size and novelty.

Conclusions: To our knowledge, this is the first analysis of the efficacy of OBTA injections for management of primary NE. A follow up clinical trial is essential to further understand this association.