Migraine surgery is a surgical operation undertaken with the goal of reducing or preventing migraines. Migraine surgery most often refers to surgical nerve decompression of one or several nerves in the head and neck which have been shown to trigger migraine symptoms in many migraine sufferers. Following the development of nerve decompression techniques for the relief of migraine pain in the year 2000, these procedures have been extensively studied and shown to be effective in appropriate candidates. The nerves that are most often addressed in migraine surgery are found outside of the skull, in the face and neck, and include the supra-orbital and supra-trochlear nerves in the forehead, the zygomaticotemporal nerve and auriculotemporal nerves in the temple region, and the greater occipital, lesser occipital, and third occipital nerves in the back of the neck. Nerve impingement in the nasal cavity has additionally been shown to be a trigger of migraine symptoms.
Indications and patient selection Migraine surgery is usually reserved for migraine patients who fail more conservative therapy or who cannot tolerate the side effects of drugs used to treat their migraines. Appropriate patients are screened using injections of local anesthesia to provide a temporary nerve block. In some cases, Botox may be used to provide temporary decompression of the nerve. Patients who respond to nerve blocks often see an immediate though temporary reduction in their pain by "shutting off" the nerve that is triggering the migraine, while pain relief following Botox injections is provided by relaxation of nearby muscle tissue that may be compressing the nerve. Patients who respond well to these screening procedures are felt to be excellent candidates for migraine surgery.
Surgical procedures Migraine surgery is an outpatient procedure which addresses peripheral nerves through limited incisions. Depending on the symptoms of the patient and the screening results following nerve blocks or Botox, different areas of the head and neck may be addressed to treat the nerves found to be the migraine trigger in a given patient. Migraine surgery is always individualized to each patient's symptoms and anatomy.
Anterior nerves Nerves found in the forehead (supra-orbital and supra-trochlear nerves) are either addressed using endoscopic surgery or by using an incision in the crease of the upper eyelid. Structures that are found pressing on the nerves here are released and may include bone at the upper orbit, fascia, blood vessels, or muscle tissue. The supra-orbital and supra-trochlear nerves travel through the corrugator supercilii muscle which enables frowning of the brow. These nerves are released from these muscles so they may lie free of pressure from these muscle structures. Small blood vessels which travel with these nerves may be divided to prevent pressure as well. In the bony notch where these nerves exit the eye socket, small pieces of bone or connective tissue may be removed so undue pressure is not placed on the nerves in this region.
Nerves of the temple region The zygomaticotemporal nerve and auriculotemporal nerves are found in areas between the top of the ear and the lateral portion of the eye, in different areas of the temple. These nerves can also be addressed by endoscopic techniques, or well hidden small incisions. Blood vessels next to or crossing these nerves are often found to be the source of compression, and these blood vessels may be divided to prevent irritation of these nerves. Associated temporal muscle release in the region of these nerves may also be indicated. Because these nerves are very small and provide feeling to small regions of the scalp, they are often cut or avulsed, allowing the ends to retract into muscle tissue to prevent neuroma formation.
Posterior nerves Chronic irritation of the occipital nerves is called occipital neuralgia and is frequently the cause of migraine symptoms. The greater occipital and third occipital nerves are addressed through an incision at the base of the scalp in the upper neck by either a vertical or transverse incision. Incisions are usually placed within the hairline. The greater occipital nerve travels through several muscle layers (including the trapezius muscle and splenius capitis muscle) where it is often compressed, and therefore surgery for this nerve involves releasing it from tight muscle and fascia in the upper neck. Blood vessels found crossing the nerve such as the occipital artery may be divided in order to avoid chronic pressure and irritation of the greater occipital nerve. The third occipital nerve is a small nerve that travels near the greater occipital nerve and may treated similarly in order to alleviate chronic irritation.
The lesser occipital nerve is a small nerve that has additionally been found to be associated with migraine pain. This nerve is found near the sternocleidomastoid muscle and may be decompressed or divided here through a small incision. Alternative techniques localize the lesser occipital nerve through the same posterior hairline incision as the greater occipital nerves. As this small nerve provides feeling for a small region of the scalp, the minimal numbness resulting from the division of this nerve often goes un-noticed.Neurostimulation surgery, in which electrical stimulators are implemented over the occipital and/or superorbital nerves, has also been used to treat migraines, although there is scarce evidence for the effectiveness of this procedure.
Nerves of the nose The nerves of the nasal lining may be impinged by structures in the nose such as the nasal septum and turbinates. Nasal surgery to decompress these regions may include septoplasty, turbinectomy, or other rhinoplasty procedures.
Surgical outcomes Though initially thought to be experimental surgery, the benefits of migraine surgery have now been well documented. Followup data has shown that 88% of migraine surgery patients experienced a positive response to the procedure after 5 years. 29% of patients have been shown to achieve complete elimination of their migraine disease, while an additional 59% of patients reported a significant decrease in their pain and symptoms 5 years following their migraine surgery. 12% of patients undergoing migraine surgery reported no change in their symptoms after 5 years.
Migraine surgery has additionally been studied in a socioeconomic context and has been shown to reduce both direct and indirect costs associated with migraine disease. Such costs after migraine surgery have been shown to be reduced by a median of $3,949 per patient per year.
Surgery
Chronic daily headache is a major worldwide health problem that affects 3–5% of the population and results in substantial disability. Advances in the medical management of headache disorders have meant that a substantial proportion of patients can be effectively treated with medical treatments. However, a significant proportion of these patients are intractable to drug treatment. The successful use of surgical procedures for the treatment of migraine is becoming more frequently reported in the medical literature, particularly for those patients who do not respond to medication. There is resistance in some quarters the concept of surgery for migraine, on the grounds that it is unnecessarily invasive. On the contrary, others argue that to undergo a relatively minor and minimally invasive once-off surgical procedure is not as invasive as having to permanently take chronic medication, which in many people has unpleasant or intolerable side effects, or is ineffective. The answer to this conundrum lies however in informed consent - the patient must be advised of all the possibilities, and of all the pros and cons of each option, so that an informed choice can be made. In some instances, patients opt for the drug route, and only take the surgical option when the medication has not had the desired effect. For others, the thought of being on chronic medication is anathema.
Arterial pain In many migraine sufferers, the pain originates in painfully dilated extracranial terminal branches of the external carotid artery. That vasodilatation is an important factor in migraine is further confirmed by the fact that the most widely used migraine rescue medications, the ergots, the triptans, and the promising newer drugs, the gepants, possess one significant common denominator: they all potently constrict abnormally dilated extracranial arteries while simultaneously reducing or eliminating migraine pain. Furthermore, to date all migraine-provoking agents have had vasodilating properties.
Arterial surgery In patients where the pain has been positively diagnosed to originate from the scalp arteries (the terminal branches of the external carotid artery), the preventive treatment of choice is surgical cauterization of the responsible arteries – known as the Shevel Procedure.
In order to pinpoint the position of the relevant arteries, a three-dimensional CT scan is done, which allows accurate visualization of the course of each artery. This is necessary, as the course of the arteries varies from person to person, and even from side to side in the same individual. During surgery, the position of the artery is further verified by means of a Doppler Flowmeter, with which one can hear the blood flowing through the vessel. Use of the three-dimensional CT scan and the Doppler Flowmeter allows the surgeon to make use of the smallest possible incision, so the procedure is minimally invasive. The most common vessels involved in the pain of migraine are the terminal branches of the external carotid artery, and in particular, the superficial temporal artery and its frontal branch, and the occipital artery, but the maxillary, posterior auricular, supra-orbital, and supra-trochlear branches may also be involved. These vessels are subcutaneous (just under the skin) and the small incisions required to access them and the minimally invasive nature of the procedure means that the surgery can be done in a day facility. As these vessels have no connection with the arterial supply to the brain, the Shevel Procedure is exceedingly safe with no unpleasant side effects. The cosmetic effect is excellent as most of the incisions are within the hairline.