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Dual Nerve Stimulation Helps Chronic Migraine
Medscape Medical News
April 15, 2014

SAN FRANCISCO ? Stimulating both the occipital and supraorbital nerves provides better relief of chronic migraine than stimulating only the occipital nerve, a new study shows.

Fourteen of 20 patients in a case series reported greater than 50% relief of their pain, said Shannon Wang Hann, MD, a neurosurgeon at Thomas Jefferson University in Philadelphia, Pennsylvania.

She presented her findings here at the American Association of Neurological Surgeons (AANS) 82nd Annual Meeting.

"I believe that the dual stimulation of the occipital and supraorbital nerve has good results for treating chronic primary headache," said Dr. Hann. "We need to improve our surgical techniques to reduce the complication rate."

Dual Stimulation
In previous studies in which just the occipital nerve was stimulated, only about a third of patients have reported at least a 50% reduction in pain, she said.

She and her colleagues reasoned that some migraine pain may originate from the front as well as the back of the patients' heads, so they tried stimulating the supraorbital nerve as well.

They enrolled 20 consecutive patients with any diagnosis of medically refractory primary headache. All the patients reported that stimulation trials in a pain clinic had cut their pain by at least half.

At baseline, the patients' average pain score on a visual analogue scale was 6.3, rising to 8.7 during acute attacks. Their symptoms had lasted for an average of 6.3 years.

Two patients had traumatic facial pain that had progressed to chronic headache. Nine patients were using narcotics to manage the pain. Seven patients had psychiatric issues, and 7 patients were on disability because of their headaches.

At follow-up ? a mean time of 34 months after the permanent implant of the stimulators ? 14 of the patients reported better than 50% improvement, including 9 patients who reported greater than 80% improvement.

The patients' average visual analogue scale scores at 6 months dropped to a baseline of 3.1 and 4.9 during acute attacks, then rose to a baseline of 3.4 and 5.2 during acute attacks at the most recent follow-up.

Five of the 9 patients who had been using narcotics were able to stop. Three patients who had tried occipital stimulation alone got better results with dual stimulation.

"Preop, none of the patients had normal productivity because they were affected with their ability to concentrate from the headache," said Dr. Hann. "But 7 of the patients postop stated that they were able to return to their previous baseline functional capacity. So I think there was some positive socioeconomic effect as well."

On the other hand, none of the patients on disability returned to work.

Six patients reported less than 50% improvement. "Patients with facial pain did not respond," said Dr. Hann. "In fact, they developed allodynia at the insertion point and had to have the stimulator removed."

Several patients experienced complications as well. Seven had lead migration erosion, 5 had lead allodynia, and 4 had infections.

The researchers are gradually developing improvements in their techniques that they hope will mitigate these complications.

For example, they recommend that female patients use a buttocks battery because 1 female patient had significant pain after her subclavicular battery was dislodged. But they still recommend subclavicular batteries for men because of the shorter distance to the stimulators.

Dr. Hann finished her presentation by calling for clinical trials of dual stimulation.

Separate Stimulation?
In the question-and-answer period, session moderator Jason M. Schwalb, MD, asked whether the researchers had specifically selected patients with frontal headaches for the study.

"If you ask where the headache is, most of the patients would just say 'all over the head'," Dr. Hann responded.

Another attendee asked whether the researchers had tried simulating the 2 nerves separately to see whether 1 worked better than the other.

"We should have had that done," responded Dr. Hann. "We never asked the patients who had occipital stimulation to turn off 1 and use only 1."

But she said some patients had infections in 1 implant and not the other, prompting surgeons to remove 1 of the leads. "For those patients we would ask the patients if the pain coverage was still good or not, and for those they typically say that after removing 1 lead the result is just not as good," she said.

Dr. Schwalb, surgical director of movement disorders and comprehensive epilepsy centers at Henry Ford West Bloomfield Hospital in West Bloomfield, Michigan, later told Medscape Medical News that the procedure "might be worth setting up a trial" for.

"It's very preliminary data, so it's hard to know what to make of it," he said.

American Association of Neurological Surgeons (AANS) 82nd Annual Meeting. Abstract 817. Presented April 9, 2014.
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