Device outcomes in pediatric sacral neuromodulation: A single center series of 187 patients

Abstract

Pediatric sacral neuromodulation (SNM) device duration before revision or removal is not well known. Furthermore, secondary surgeries serve as surrogates for key outcomes including complications and symptom improvement. We sought to study the rate and causes of secondary surgeries in pediatric SNM patients. We assessed our cohort of pediatric SNM patients for secondary surgeries (revision or removal). Baseline patient characteristics associated with secondary surgery were analyzed with Fisher's exact test. Kaplan-Meier analysis was used to describe secondary-surgery-free device survival. 187 pediatric patients underwent sacral neuromodulation at our institution between 2002 and 2019. 7 (4%) patients did not have a permanent device placed due to poor response during an externalized lead trial period, leaving 180 patients with permanent implanted devices. Over a median follow-up of 3.9 years (IQR 2.0 to 6.3), there were 154 total secondary surgeries. There were 83 device revisions, with 89% of revisions for a non-functioning device, 8% for pain, and 2% for infection. Of the non-functioning devices, 11% were due to battery depletion and the rest were due to lead fracture or dislodgement. Permanent device removal was performed in 71 (39%) patients, with 38% of these for unfavorable reasons (6% infection, 8% pain, 24% no longer effective) and 62% for favorable reasons (symptom improvement or resolution). Of patient baseline characteristics, only device duration was associated with favorable removal (p<0.01). On Kaplan-Meier analysis, 5 year device secondary-surgery-free survival was 32% for any secondary surgery (favorable or unfavorable) and was 47% for unfavorable secondary surgery. At last follow-up, 74% of patients were in a favorable position (using the device, trialing with device off, or device had been removed for improvement) while 26% of patients were requiring other treatments due to device problem or removal. Describing the likelihood of subsequent surgery is an important aspect of patient and guardian counseling concerning pediatric SNM. Our cohort had a 68% 5 year all-cause reoperation rate. However, in a theoretical perfect world, pediatric SNM reoperation rate would be 100% after adequate follow-up (either for battery replacement, or device explantation for improvement). While sacral neuromodulation in our cohort of children carried a high (68% 5-year) reoperation rate (whether for complication or symptom improvement), the majority (74%) of these patients with previously refractory symptoms either continue to use their device or have had significant symptom improvement to permit device removal at moderate-term (median 3.9 year) follow-up.