Electrical stimulation of the spinal accessory nerve during neck dissection for head and neck cancer may reduce the development of shoulder dysfunction, according to a double-blind randomized controlled trial.1 A year after surgery, patients given intraoperative electrical stimulation had significant improvements in scores that capture shoulder pain, range of motion, strength, and activities of daily living when compared to their control peers, investigators reported at the 9th International Conference on Head and Neck Cancer. They also had a dramatically smaller decline in the nerve conduction amplitude of the shoulder muscles at 1 year compared to baseline.
This is the first study to demonstrate brief intraoperative electrical stimulation can lead to significantly better preservation of shoulder function after oncologic neck dissection in head and neck cancer patients.— Brittany R. Barber, MD
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“This is the first study to demonstrate that brief intraoperative electrical stimulation can lead to significantly better preservation of shoulder function after oncologic neck dissection in head and neck cancer patients,” commented first author Brittany R. Barber, MD, a surgical resident at the University of Alberta in Edmonton, Canada. “This was a single-institution study with a high rate of patient attrition and death, which did limit our ability to perform subgroup analyses,” she noted. “However, we plan to address this with a larger multi-institutional trial.”
Intraoperative electrical stimulation may ultimately have applicability to other nerves that are affected by surgery for head and neck cancer, according to Dr. Barber. “We had initially wanted to study this for the hypoglossal nerve. My senior authors, Daniel O’Connell, MD, MSc, FRCSC, and Hadi Seikaly, MD, MAL, FRCSC, thought it would be a cleaner study to start by showing efficacy with the spinal accessory nerve, because it would be less affected by variation in reconstruction,” she explained. “But we are looking into it.”
Background and Rationale
During neck dissection, surgeons must retract and manipulate the spinal accessory nerve to gain access to lymph node levels IIb and V, Dr. Barber commented. “However, these actions can often give rise to nerve damage, which in turn can give rise to shoulder dysfunction and pain.” This surgical complication may have a substantial negative impact on quality of life and, as the majority of patients with head and neck cancer are male and still of working age, on socioeconomic outcomes.
K. Ming Chan, MD, FRCPC
“Over the past 2 decades, animal studies have demonstrated that application of brief electrical stimulation to transected motor and sensory nerves can improve axonal outgrowth and regeneration,” noted Dr. Barber. Some positive results have been demonstrated by our coauthor, K. Ming Chan, MD, FRCPC, in research among humans treated after carpal tunnel release or transection of the digital nerve.
Study Details
The trial investigators enrolled adults from their tertiary-care center who had newly diagnosed head and neck cancer and were undergoing oncologic neck dissection of multiple nodal basins, including level IIb with or without level V. In total, 54 patients were randomized evenly to undergo intraoperative electrical stimulation of the spinal accessory nerve (60 min continuously at 20 Hz, 3–5 V, in 100-μsec pulses) or a control condition of sham stimulation. All patients had blinded assessments of shoulder function and nerve conduction amplitude before and 12 months after surgery.
Preventing Shoulder Dysfunction From Neck Dissection
- A randomized trial of 54 patients undergoing neck dissection for cancer found less worsening in shoulder function at 12 months with intraoperative electrical stimulation of the spinal accessory nerve vs sham stimulation.
- The electrical stimulation group also had a much smaller decrease in the nerve conduction amplitude of the trapezius muscle (–0.49 vs –4.04 mV).
Overall 65% of the study patients had neck dissection of level IIb alone, whereas the other 35% had dissection of both levels IIb and V, Dr. Barber reported. On average, 73 lymph nodes were removed.
Preservation of Shoulder Function
At 12 months, patients given intraoperative electrical stimulation had much less worsening of shoulder function than their control peers, as assessed by physiotherapist Margaret McNeely, PT, PhD, with the 100-point Constant-Murley Score, the trial’s primary endpoint (–8.4 vs –29.4 points, P = .022). (The minimally important clinical difference for this score is 10 points.)
The electrical stimulation group also had a smaller reduction in nerve conduction amplitude of the trapezius muscle, as assessed by a neurophysiologist (–0.49 vs –4.04 mV). They also had an almost 50% drop in the Neck Dissection Impairment Index, as rated by patients (–16.2 vs –30.1 points), although this change did not quite reach the minimally important clinical difference for this index of 18 points. ■
Disclosure: Dr. Barber reported no potential conflicts of interest. Dr. O’Connell is a paid consultant for Medtronic Canada for intraoperative nerve monitoring during thyroid/parathyroid surgery.
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