Is sensory testing during lead placement crucial for achieving positive outcomes after sacral neuromodulation?

Abstract

Motor and sensory responses help guide lead placement during staged neuromodulation procedures. However, eliciting sensory responses requires lighter anesthesia. We evaluated the impact of assessing sensory responses during quadripolar tined lead placement on outcomes in subjects with refractory voiding symptoms. Adults who had a sacral lead placed were identified from our prospective neuromodulation database and grouped by whether they had intraoperative sensory testing or not. History, operative data, and implantable permanent generator (IPG) implant, lead revision and device explant rates were collected from medical records. Symptoms were evaluated with the Interstitial Cystitis Symptom Index/Problem Index (ICSI-PI) and scaled global response assessments (GRA) for the first 24 months post IPG placement. Data were analyzed using Pearson's Chi-square, Fisher's Exact, or Wilcoxon rank test. Of 141 subjects (82% female), 86 (61%) had sensory testing and 55 (39%) did not. Sensory and no sensory testing groups were not significantly different on demographics, urologic diagnosis, IPG implant rates (76/84; 90% and 48/55; 87% respectively) or mean operative time (37.9 ± 13.9 minutes vs. 35.5 ± 11.6). Within 4 years, 19/141 (13.5%) were revised and/or explanted. For explant alone, 11/86 (13%) in the sensory and only 3/55 (5.5%) in the no sensory group (P = 0.16) were explanted. Overall, ICSI-PI scores improved over time (P < 0.0001) and most reported improvement on the GRA at each time point, but no differences were seen between groups. Intraoperative sensory testing during sacral lead placement does not necessarily improve IPG implantation rates or clinical outcomes of neuromodulation.