Nasal surgery might help alleviate severe migraine headaches for some patients, research suggests.
One in 10 Britons suffer migraines
It seems some migraines are triggered - or exacerbated - by opposite surfaces within the sinuses or nasal cavities pressing against each other.
The brain is confused into interpreting the stimulation as a headache.
New Jersey researchers found endoscopic nasal surgery on 21 migraine sufferers halved the number of days they had headaches and they were less severe.
The study, by Christ Hospital in Jersey City, New Jersey, is published in the journal Cephalagia.
It has been known that when opposite surfaces in the nasal cavity touch and press against each other they stimulate one of the main nerves in the face called the trigeminal nerve; which in turn causes secretion of a special substance that is irritant to the nasal tissue.
When this occurs it has known in certain instances to confuse the brain into interpreting the stimulation as a headache - a phenomenon known as referred pain.
The researchers evaluated 21 patients who had severe migraines that had not responded to conventional treatment.
CT scans of the sinuses revealed that these 21 patients had intranasal contact points.
When the contact points were treated with insertion of cotton pledget soaked in decongestant and anesthetic solution all 21 patients experienced temporary improvement in their symptoms.
The same group of patients underwent endoscopic modified sinus surgery to correct the contact areas.
In the months after the surgery, the average number of days with headache experienced by the group fell from 18 to eight days per month.
The average headache severity, measured on a 10-point scale, dropped from 7.8 to 5.6.
Nine of the patients had no headache symptoms at all at their last follow-up.
Lead researcher Dr Fereidoon Behin said: "We are very excited. We believe a good percentage of patients whose migraines ares linked to intranasal contact points problems can be cured by this operation."
Dr Andrew Dowson, medical advisor of Migraine Action Association, told the BBC News website nasal pain was often misinterpreted as migraine, and that it was possible that the two conditions were linked.
His own research has shown that patients with a condition called patent foramen ovale - known colloquially as a hole in the heart - are at greater risk of migraine. "Migraine is probably a neurological condition," he said.
"Conditions such as intranasal contact points and a hole in the heart probably generate added 'neurological noise'.
"This may be enough to tip the balance in an already disturbed nervous system and trigger a migraine attack."
However, Dr Dowson said more work was needed before it could be conclusively shown that these conditions were a significant factor in migraine.