Why and When do we Remove a Sacral Neuromodulation Device? Results from the Sacral Neuromodulation Alliance for Pediatric Patients (SNAPP)
Benjamin Abelson, MD1, Seth A. Alpert, MD2, Mason Graham, MPH1, Shilin Zhao, PhD1, Alexandra W. Rehfuss, MD2, Carley M. Lutz, BS2, Jordan Apfeld, MD2, Sally R. Dunn, NP3, Shelly J. King, NP3, Benjamin M. Whittam, MD3, John C. Pope, IV, MD1.
1Monroe Carell Jr. Children's Hospital at Vanderbilt, Nashville, TN, USA, 2Nationwide Children's Hospital, Columbus, OH, USA, 3James Whitcomb Riley Children's Hospital, Indianapolis, IN, USA.
BACKGROUND: Sacral neuromodulation (SNM) has become a treatment option for children with refractory voiding dysfunction, with the optimal outcome being surgical removal after sustained improvement in symptoms even after device deactivation. However, multi-institutional long term outcomes after stage 2 SNM placement are lacking. We aimed to define the cause and timing of elective removal of 2 stage SNM and to identify predictive factors for success of SNM in children with non-neurogenic refractory voiding dysfunction. METHODS: A prospective multi-institutional database from 2010-2018 was queried for all 2-stage SNM patients. Patients whose devices were electively removed were categorized into 2 groups: successes (symptoms resolved with device off) and failures (removal required for reasons other than success). We excluded device removals performed for device infection. Clinical data and voiding score symptoms were collected. Analysis was conducted and statistical significance was set a priori at p<.05. RESULTS: 196 patients had successful 2-stage SMN procedure. Median age was 15.9 years (IQR 12.95-17.8), 131 (67%) were female, 111 (82%) were white/Caucasian, 112 (59%) were privately insured, and median BMI at time of 1st stage was 21. A total of 90% of patients reported at least 75% perceived improvement compared to baseline at their last follow-up visit. Forty patients had their device electively removed for non-infectious reasons: 24 for success, 16 for failure. Median time to removal was 48.5 (35.5 - 68.8) months for the success group and 28.0 (14.5 - 46.0) months for the failure group. Failures were categorized as: persistent symptoms (6/16, 38%), untoward effects (2/16, 12%), patient non-compliance (2/16, 12%) or other (6/16, 38%). There were no differences in demographic variables, prior treatments, BMI, completion of pre-operative urodynamics, or voiding questionnaire scores between the successful and failure removal groups.
CONCLUSIONS: Within our large, multi-institutional cohort, we demonstrate high likelihood of success after 2-stage SNM and that 40/196 (20%) of SNM devices have been removed for non-infectious reasons: 24 (60%) for success and 16 (40%) for failure. Despite the multi-institutional effort, the small number of events precluded additional analysis to determine preoperative indicators of successful removal. Additionally, this study provides useful counseling data regarding likelihood of device removal for either success or failure.
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