Severe migraines are now being treated by Genesis — an implanted electrical stimulator.
Placed just under the skin, the device turns off the painful symptoms by sending out electrical signals that interfere with the pain messages travelling along the nerve to the brain.
Three patients in Britain have been successfully implanted with the technology, and doctors are enthusiastic about what could be a major new form of treatment for those people whose migraine has failed to respond to other therapies.
‘It is not something you will give to people who have failed to control pain with a few paracetamol or codeine, but there are patients who will benefit enormously,’ says Professor Peter Goadsby of the National Hospital for Neurology and Neurosurgery in London.
‘It is a nondestructive, safe way to move ahead with a group of people who are otherwise completely lost. The results have been very good so far.’
Whether or not patients are eligible for the treatment is down to clinicians. Diagnosis is usually made on the severity of symptoms and how disabling they are rather than how long the individual has suffered.
Migraine affects around 12 per cent of the population, with women more likely to suffer than men.
In classical migraine, or migraine with aura, the headache is preceded by visual disturbances which may include flashing lights and blind spots. The aura usually disappears after 20 to 30 minutes and is followed by a piercing, often one-sided headache, and sensitivity to light.
Patients may experience a migraine every day, several times a week or once or twice a year. Migraines may be so severe they interfere with a patient’s ability to work and carry on normal activities.
The exact cause of migraines is unknown, but it is likely that a combination of factors contribute, including nerves, blood vessels, brain chemicals and environmental triggers
One theory is the nervous system reacts to a trigger with electrical activity that spreads across the brain, leading to the release of chemicals that make blood vessels swell and become leaky. Scientists believe this process may cause the pain and other symptoms.
Although there is a range of treatments for migraine there is no cure, and for some people the symptoms are so severe they are not helped by available treatments.
The new treatment being pioneered in Britain and America, the Occipital Nerve Stimulator, is aimed at that group of patients with intransigent migraine.
The device is designed to stimulate the occipital nerve at the back of the head, which connects with all the pain-sensitive areas of the skull.
It is not a brain implant, but sits just under the skin. As a result, it’s simple to implant, and in some cases the device can be put in place with a local anaesthetic.
Usually, a battery lies under the skin by the collarbone, and a small wire runs up the neck and into the scalp.
Blocking nerves with drugs stops pain signals going to the brain and it’s thought that the stimulator has the same kind of effect by mixing up the signals going to the brain.
‘When information comes into the body it goes into the nerve cells, where it is processed. Those nerve cells project all the senses and feeling to a small part of the brain, the thalamus.
‘It looks as though by stimulating the input, you can affect the way it thinks about pain. It interferes with the signals and turns the pain processing off,’ says Professor Goadsby.
‘It is not a cure – it is a permanent treatment, and seems to work indefinitely.’
More cases of migraine have been treated by doctors in America using the same technique and a review of progress so far is expected to be published early in the new year.
The same kind of nerve stimulation technology is also being used for different kinds of pain, including other forms of severe headaches. One 40-year-old American man who was having up to five cluster headaches a day had far fewer after receiving an implant.
A woman who had face and head pain has also been successfully treated. A tiny electrode attached to a needle was tunnelled under the skin by her left eye until it came into contact with the nerve responsible for her pain.
Powered by a battery implanted near her collarbone, the device now continually stimulates the nerve with electrical pulses. The pain stopped the moment the active electrode touched the nerve.
Another patient has also been given nerve stimulation for severe shoulder pain. After it was switched on, he had an 80 per cent drop in pain levels.