Pediatric Sacral Nerve Stimulator Explanation due to Complications or Cure: A Survival Analysis

Abstract

Introduction Historically, there have been few treatment options for children with severe, refractory bladder and bowel dysfunction (BBD). Sacral neuromodulation (SNM) continues to show promising results in this challenging pediatric population with recalcitrant lower urinary tract symptoms. At our institution, we have begun offering explantation to those with persistent improvement after >6 months of having device turned off. We hypothesized that 1.) SNM explantation for cure increases with extended follow-up, and 2.) those explanted for cure would have improved symptoms and quality of life when compared to those explanted for complication.

Materials & Methods We retrospectively reviewed all consecutive patients <18 years old who underwent SNM placements at our institution (2012-2017). We excluded those without the second stage procedure. Reasons for device explantation were categorized as: cure (resolution of symptoms with the device turned off for at least 6 months), or a complication (e.g. infection, need for MRI, or pain). Non-parametric tests and survival analysis were used for analysis to account for differential follow-up time. Of those explanted, surveys were electronically sent to assess BBD severity, and overall quality of life.

Results Of 67 children who underwent a first stage procedure, 62 (92.5%) underwent a second stage procedure. 61 met inclusion criteria (68.9% female, 29.5 % with previous filum section, median age at implantation 10.3 years old). During follow-up (median 2.3 years), 12 patients (19.7 %) had the SNM exchanged/revised due to lead fracture/breakage and return of urinary symptoms. To date, 50 patients remain with their SNM implanted, and 11 have been explanted. Adjusting for follow-up time, the risk of explantation was 6.5% at 2 years (2.2% for cure, 4.3% for complications) (Figure 1). Explantation increased to 24.5% at 3 years (16.5% for cure, 8.0% for complications) and 40.4% at 4 years (32.4% for cure, 8.0% for complications). Questionnaires were collected on patients post explant (median 2.2 years), with improvement in those explanted for cure compared to complication (Figure 2).

Discussion SNM explantation for cure is a novel concept previously not described in the literature. Limitations of this study include the relatively small numbers, and lack of objective data in the cohort that remains with SNM device implanted.

Conclusion SNM is a safe, viable option for the pediatric patient with refractory bladder dysfunction. Furthermore, SNM explantation for cure is an option with increasing likelihood after two years.