Intraoperative nerve stimulation reduces risk of shoulder problems from neck dissection

AT AHNS 2016

SEATTLE (FRONTLINE MEDICAL NEWS) – Direct, intraoperative electrical stimulation of the spinal accessory nerve reduced shoulder pain and dysfunction from oncologic neck dissection in a small, randomized trial.

Shoulder problems are common after neck dissection because of traction and compression of the spinal accessory nerve. Although brief electrical stimulation (BES) has been shown before to improve regeneration and recovery of injured peripheral nerves, it hasn’t been shown until now to help patients recover from neck surgery, said investigator Brittany Barber, MD, a fifth-year resident at the University of Alberta, Edmonton.

After neck dissection in 21 patients, the investigators wrapped a small electrode (Automatic Periodic Stimulation [APS] electrode, Medtronic) around the spinal accessory nerve at the base of the skull on the side of the neck with the most extensive nodal burden; the electrode delivered 100-msec pulses at 20 Hz and 3-5 V for an hour, and then the neck was closed. The team compared outcomes with 20 controls who had neck dissections without BES.

At 12 months, the BES group had an 8.4 point drop from baseline on the 100-point Constant Murley Shoulder Outcome Score, while the controls lost a mean of 29.4 points. The Murley score measures shoulder pain, performance of daily tasks, range of motion, and strength; higher scores are better. Similarly, BES patients lost a mean of 16.2 points on the 50-point Neck Dissection Impairment Index, while controls lost 30.1 points, and controls performed markedly worse on nerve conduction studies. In short, BES patients “were less likely to have clinically significant shoulder dysfunction” after surgery, Dr. Barber said at the International Conference on Head and Neck Cancer, held by the American Head and Neck Society.

The APS electrode is a tiny silicone cuff with a metal conductor. The device was originally designed to monitor recurrent laryngeal nerve function during thyroid surgery. “We had [Medtronic] write a software patch” so it could be used for stimulation, she said.

The team is planning a larger, multicenter trial to shore up their findings, and also plans to test the device for hypoglossal nerve preservation after resection.

Transcutaneous nerve stimulation is another option, but it’s a bit uncomfortable and patients often don’t complete their sessions. “Compliance is not as good as with a single intraoperative procedure,” and the results aren’t that great. “We thought this might be a better alternative,” Dr. Barber said.

The two groups were well matched: Mean age was about 60 years and most patients had advanced-stage tumors. There was no difference in preop shoulder problems or risks for poor postop shoulder outcomes, and no difference in the number of level 5 neck dissections or mean number of lymph nodes removed during surgery.

There was no outside funding for the work. Dr. Barber had no disclosures; a coinvestigator was a Medtronic consultant.


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