Sacral nerve stimulator success after filum section for refractory dysfunctional voiding

Filum section (FS) has been used to treat tethered cord syndrome (on MRI or occult) in pediatric patients with refractory dysfunctional voiding (DV). While controversial, some groups have previously reported significant improvement in patients' symptoms after FS, even in the presence of a normal preoperative spinal MRI. Until recently, it was our practice to refer patients with DV to pediatric neurosurgery for evaluation, MRI, and possible FS.

We report our experience with sacral nerve stimulator (SNS) placement for pediatric patients with refractory DV after failed FS with the primary outcome being complications and explantations. The secondary outcome being change in quality of life.

We retrospectively reviewed all consecutive patients <18 years old who underwent second stage SNS placement after FS at our institution between November 2012 and December 2019. We abstracted rate of 2nd stage implantation, complication, and explantation. We also collected age-appropriate preoperative and postoperative 15-question quality of life questionnaires (PedsQL™). The PedsQL scores ranged 0-100, higher numbers correlating with higher quality of life. A paired t-test was used for statistical analysis.

Overall, 23 children proceeded to the second stage SNS due to persistent symptoms following FS. Median age at SNS implantation was 10.3 years (IQR 7.5-11.8 years), and 13 were female (56.5%). There were no intraoperative complications. Median follow-up was 2.8 years (IQR 1.1-3.7 years). One patient had the SNS removed due to a need for MRI, one for resolution of symptoms, and 4 patients underwent lead revision for lead fracture and return of symptoms (17.4%). All 15 patients who completed both preoperative and postoperative PedsQL reported significantly improved overall scores after SNS (Figure). Median scores improved from 61.7 to 86.7 (p < 0.0001).

Symptom relief in the child with refractory DV using SNS is not new. However, we sought to review our results in those with previous FS for tethered cord syndrome. While our study is limited by its small size, we assessed both surgical and patient-reported outcomes. Our patients' marked improvement in quality of life is similar to that of other reported pediatric SNS cohorts.

SNS placement after FS is feasible, safe, and can result in significant improvement in overall quality of life. Given these findings, we have changed our practice to offer SNS in patients with refractory DV with a normal lumbosacral spinal MRI. For those with MRI abnormalities, we seek neurosurgical evaluation for FS (if deemed necessary) prior to considering SNS.