New York, Nov 4 (IANS): The unbearable headache that migraine patients suffer is due to cellular-level changes in nerve structure, says a study.

The researchers found abnormalities of the myelin sheath that serves as "insulation" around the nerve fibers.

"Essentially, the protective layer surrounding and insulating the normal nerves, called myelin, is missing or is defective on the nerves of the patients with migraine headaches," said Bahman Guyuron from Case Western Reserve University, Cleveland.

The findings suggest a plastic surgery procedure could provides effective pain relief for migraine patients - and may provide useful clues for developing new approaches to migraine treatment, shows new research.

Guyuron likens the myelin sheath to the plastic coating used as insulation material around electrical wires and cables.

"If the insulation becomes cracked or damaged by conditions in the environment, that is going to affect the cable's ability to perform its normal function," Guyuron pointed out.

"In a similar way, damage to the myelin sheath may make the nerves more prone to irritation by the dynamic structure surrounding them, such as muscle and blood vessels, potentially triggering migraine attacks," he added.

The researchers performed in-depth studies on tiny specimens of the trigeminal nerve (one of the cranial nerves), from 15 patients who underwent surgical treatment for migraine.

Sample from 15 patients undergoing a cosmetic forehead lift procedure were studied for comparison.

The results showed important differences in nerve structure between the migraine and cosmetic surgery patients.

Organisation of the cellular elements in nerve fibers also differed between groups.

Healthy nerves were tightly organised with elements uniformly distributed through the nerve, while nerves from migraine patients showed discontinuous, "patchy" distribution.

The study appeared in the journal Plastic and Reconstructive Surgery.