Nerve Stimulation Gains Ground in Headache Treatment

Pauline Anderson

July 03, 2013

BOSTON — Various modes of nerve stimulation are showing promise in the management of treatment-resistant headache, new research suggests.

One noteworthy stimulation site is the sphenopalatine ganglion (SPG), a small collection of nerve cells located behind the nose, components of which are involved in the pathophysiology of cluster headaches.

The SPG has been a well-known therapeutic target for headache relief for more than 100 years. In the past, application of cocaine, alcohol, and corticosteroids and the injection of alcohol were among the attempted treatment approaches.

Now, researchers are testing the electrical stimulation of this site using an implantable remote-controlled system. One promising new study of this system included patients at 6 centers in Europe who had cluster headaches with a minimum of 4 attacks per week.

The findings were presented here at the 2013 International Headache Congress.

Novel System

"This is a novel system; it's implantable; it has either an acute efficacy and/or a headache frequency reduction in 63% of patients," and it's safe and tolerable, said study author Rigmor Jensen, MD, Glostrup Hospital, University of Copenhagen in Denmark.

For the study, participants underwent surgical implantation of a very small, minimally invasive neurostimulator with electrodes placed over the SPG. The implant procedure leaves no visible scars, said Dr. Jensen.

Patients were given a wireless handheld device to place on the cheek near the implant to trigger electrical stimulation of the implant "on demand" or when they had an acute attack, she said.

Patients were randomly assigned to a treatment stimulation or a sham stimulation.

Following implantation, there was as 6-week stabilization period, followed by an experimental period of at least 3 weeks.

Of the 43 participants enrolled, 38 completed the experimental phase (a few failed to complete it due to lead migration or lead positioning). The mean age of these patients was 43 years, and most (89%) were men.

The mean duration of disease for these patients was 10 years. Most, said Dr. Jensen, had tried and failed other treatments and "had been chronic for years so were severely impaired."

Pain Relief

At 15 minutes following stimulation, 55% of the treatment group had pain relief compared with 6% in the sham treatment group (P < .0001). The pain relief was maintained to 90 minutes (50% pain relief for treatment group vs 13% for sham).

There was a reduction in average cluster attack frequency of 89% in 42% of patients, said Dr. Jensen. In addition, those receiving the treatment used fewer acute medications within 90 minutes (44% for stimulation vs 77% for sham; P < .0001).

There were no infections requiring surgical interventions and no late lead migrations. Most patients experienced typical surgical side effects, such as mild to moderate sensory disturbances within the first 30 days after implantation.

Twenty-eight patients completed a survey at 1 year post-implantation. Survey findings included the following:

  • Most (93%) said the stimulation sensation was tolerable, that the device was comfortable or could not be felt (86%), and that surgical effects were tolerable (82%).

  • The majority of patients (61%) indicated that they experienced significant overall improvements in headache disability, and 79% had improved quality of life. "That's very important in these severely affected patients," commented Dr. Jensen.

  • A significant number of patients (39%) were able to stop or reduce preventive medications.

  • Patient satisfaction was very high, with about 71% evaluating the system as good or very good, 86% saying they would make the same decision again, and 96% would recommend the system to others.

Asked by a delegate how she would compare SPG stimulation with stimulation of the occipital nerve region, located just beneath the skin at the back of the head, Dr. Jensen said that from her limited experience, she considers occipital nerve stimulation to be more invasive and could involve more problems with the leads and with infections. However, she said, she's pleased that there is now a "whole armamentarium" of options to learn about.

"It's very important that we have good study designs, that we have good evidence for these devices, and that we choose the right patient for the right treatment. That's really a challenge."

According to David Dodick, MD, professor of neurology, Mayo Clinic, Phoenix, Arizona, there is a plan in the works for a randomized controlled trial of SPG stimulation in headache treatment to begin in the United States either late this year or early next year.

Elsewhere at the headache meeting, US researchers reported 1-year results of a study of headache relief using another stimulation site — the occipital nerves — in patients with chronic migraine. For this procedure, a thin wire containing electrodes is implanted under the skin; the wire extends to an implantable battery-driven impulse generator.

Occipital Stimulation

In this prospective, multicenter, double-blinded study, patients who underwent implantation with this neurostimulation system were randomly assigned either to an active treatment group or to a control group for 12 weeks. Patients then continued in an open-label phase of the study for an additional 40 weeks.

The study found that for the intention-to-treat population of 133 individuals, headache days were significantly reduced by 6.7 days (P < .001). Migraine disability assessment (MIDAS) scores were significantly reduced by 50.9 points to a mean score of 106.7 points (P < .001),

Total pain and distress (PAD) scores were significantly reduced by 10.3 points from a mean baseline score of 66.8 points (P < .001). In addition, 65.4% of patients reported excellent or good headache relief, and patient satisfaction was also high.

The authors, led by Dr. Dodick, concluded that the results provide long-term evidence to support efficacy of peripheral nerve stimulation of the occipital nerves for the management of chronic migraine.

"There appears to be a population of patients who respond to occipital nerve stimulation, but patient selection continues to be a challenge, particularly for a relatively invasive procedure," said Dr. Dodick. "Although my colleagues in surgery would think this is a cakewalk, for a neurologist, it looks pretty invasive."

He added that the complication rates for problems such as lead migration and persistent numbness and pain at the site where the battery was implanted "are not inconsequential."

"So for a relatively invasive procedure which, at least in this country, costs upwards of $50,000 to $60,000, we surely need better randomized controlled trials," he said.

The SPG nerve stimulation long-term study was supported by Autonomic Technologies, Inc. Dr. Jensen has received honoraria for lectures from Allergan, Berlin-Chemie, and MSD, and he serves on the scientific advisory board for Allergan and MedoTech. Within the past 4 years, Dr. Dodick has served on advisory boards and has consulted for and received travel reimbursement from Allergan, Alder, Amgen, Pfizer, Merck, Coherex, Ferring, Neurocore, Neuralieve, Neuraxon, NuPathe Inc., MAP, SmithKlineBeecham, Boston Scientific, Medtronic, Inc., Nautilus, Eli Lilly & Company, Novartis, Colucid, GlaxoSmithKline, Autonomic Technologies Inc., MAP Pharmaceuticals, Inc., Zogenix, Inc., Impax Laboratories, Inc., Bristol Myers Squibb, Nevro Corporation, Arteaus, Ethicon – Johnson & Johnson. He has received consulting fees/honoraria from Allergan.

2013 International Headache Congress 2013. Abstract 58. Presented June 28, 2013.

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