Peripheral Nerve Stimulation and Clinical Outcomes

PURPOSE Peripheral nerve stimulation (PNS) is a rapidly expanding field within neuromodulation; however, there is limited data on therapeutic efficacy. This study describes the indications and clinical outcomes for patients undergoing PNS for chronic pain states.

PATIENTS AND METHODS This is a retrospective case series of adults undergoing PNS implantation from 2004-2017 at an academic medical center. The primary outcomes were changes in numeric rating scale (NRS) pain scores, opioid utilization in oral morphine milligram equivalent (MME), and self-reported patient functioning at 6 months postoperatively. Infectious and device-related complications were also assessed.

RESULTS A total of 72 patients underwent PNS implantation, including 59 patients that received a preceding PNS trial (59/78; 76% progression rate) and 13 that did not receive a PNS trial. The most common indication for stimulation was occipital neuralgia (47%) followed by lower extremity neuropathies (17%). PNS implantation was associated with 6-month reductions in pain scores [7 (6, 8) baseline vs. 4 (2, 5) 6-months; p<0.001] and opioid utilization [e.g. median 60 (31, 104) vs. 18 (0, 52) MME amongst those with baseline opioid use; p<0.001]. Median functional improvement was 73% (50%, 88%). Seven patients (10%) suffered a postoperative surgical site infection at a median of 50 (30, 124) days, of which 5 devices were removed.

CONCLUSION PNS was associated with reduced pain scores, lower opioid utilization, and improved patient function at 6-months. These data support PNS as a potentially effective non-opioid analgesic modality in chronic pain, though prospective multicenter evaluation is warranted to evaluate longer-term outcomes.