Percutaneous analgesic device enabling both local anesthetic delivery and electrical stimulation (neuromodulation) of peripheral nerves: a pilot feasibility study (case series).

Abstract

A novel device integrating both local anesthetic delivery and peripheral nerve stimulation (PNS) to treat postoperative pain is under development. The device uses a catheter-over-needle design that permits ultrasound-guided percutaneous insertion. An integrated electrode and pulse generator enable PNS for up to 28 days. Such an approach may represent a paradigm shift in postoperative pain management by enabling the delivery of (1) a single-injection peripheral nerve block, (2) a continuous peripheral nerve block, and (3) neuromodulation-all through a single system that can be placed in a timeframe comparable with that of a traditional single-injection nerve block. The current prospective pilot study was executed under a US Food and Drug Investigational Device Exemption to develop insertion and management protocols, as well as assess the feasibility and safety of using the device to treat postoperative pain. Preoperatively, adults (n=20) undergoing moderate-to-severely painful ambulatory shoulder or foot/ankle surgery had a device (RELAY, Gate Science, Moultonborough, NH) inserted under ultrasound guidance adjacent to the brachial plexus or sciatic nerve, respectively. Accurate insertion was confirmed with a 10 mL bolus of lidocaine <i>via</i> the catheter followed by bupivacaine (10 mL). If a continuous infusion was indicated, a portable pump was used to infuse ropivacaine (6-8 mL/h, 500 mL reservoir). Electric current was delivered using the integrated pulse generator for 7 days, followed by removal at home. Participants were contacted for data collection on postoperative days 1-5, 7, 8, and 14. During the first seven postoperative days, the median (IQR) "average" daily <i>pain intensity</i> as measured with the numeric rating scale (NRS) was 2 [0, 3]. Following postoperative day 1, daily average and maximum/worst NRS was less than 2 and 5, respectively. Regarding the "worst" (maximum) pain level over the entire study period of Days 0-14, 7 (35%) experienced mild pain (NRS<4), 10 (50%) moderate pain (NRS 4-7), and 3 (15%) severe pain (NRS>7). Cumulative oxycodone consumption the first week was a median of 43 (18, 73) mg. This novel device successfully delivered a single-injection local anesthetic bolus, a continuous perineural infusion, and concurrent/subsequent electrical current. A randomized, sham-controlled clinical trial appears warranted. CLINICALTRIALSGOV : NCT06818708.