3.5 Surgical Treatment of Migraine Headaches

 

[Note: Approximately 4.9 million Australians (about 20% of the population) live with migraine, with the condition disproportionately affecting women and people of working age. It is more common in females, who are roughly twice as likely as males to be affected, with prevalence peaking between 25 and 55 years of age. Trigeminal Neuralgia can trigger, or be associated with, migraine attacks. The trigeminal nerve is heavily involved in both conditions, often acting as the pathway for headache pain and facial sensations.]

The diagnosis of chronic migraine headaches should be performed first by a neurologist or other migraine headache specialist, based on the most up-to-date criteria from the International Headache Society. Next, a migraine headache journal, kept for at least 1 month, that documents the frequency, severity, and potential sites of the head and neck where the migraine headache pain may have originated is key to identifying surgical candidates. Frequent identification of specific site(s) of pain reveals “trigger sites” that may benefit from migraine surgery. Diagnostic procedures such as nerve blocks, injections of botulinum toxin (typically called Botox), and Doppler ultrasound may be useful in confirming trigger sites. At the time of a developing migraine headache, patients may be able to point to one or more sites of tenderness where the pain started, and if local nerve blocks performed at these site(s) improve symptoms, the patient would likely benefit from surgery at these site(s). Patients who present without a migraine attack are often able to recall and point to trigger sites based on memory. If injections of botulinum toxin into the muscles surrounding these specific site(s) lead to a significant improvement in symptoms over the next several months, the patient would likely benefit from surgery at these site(s). On the other hand, patients with vague, diffuse areas of pain at the start of a migraine attack or ocular migraine headaches are not surgical candidates.

The initial surgical treatment for migraine headaches involves thorough decompression of the affected nerves at the identified trigger site(s). Decompression primarily involves performing myectomies and/or fasciectomies (i.e., removing muscle and/or thin connective tissue surrounding the involved trigeminal or cervical nerve branch at the identified trigger site[s]). Doppler ultrasound at trigger sites is performed to help identify arterial branches that may be irritating a nerve, where arterectomy (or plaque removal, also called atherectomy) should be performed. Analysis of computed tomographic images is useful in identifying supraorbital foramen or notches, where osteotomies (bone removal) and fasciotomies, respectively, can be performed to release the nerve. After decompression, fat grafts are placed beneath or around the freed-up nerve at frontal and occipital trigger sites to pad the nerve from cicatricle changes and manage dead space after a myectomy. Neurectomy of a nerve branch is occasionally performed as a last resort during revision surgery in patients with persistent migraine headache symptoms after initial decompression; some improvement is obtained at the expense of temporary or permanent numbness in the dermatome for that nerve branch. Fat injection may be used as an adjunct either at the time of initial surgical decompression or at a later treatment date for patients with recalcitrant migraine headache symptoms following surgical decompression.

Traditionally, 73% of migraine headache patients treated with surgical decompression need multiple trigger sites (average of 2.6 sites) decompressed at the time of surgery. With fat injection, most patients (76%) need only one site to be injected (with a mean of 1.28 sites injected per patient). Generally, these procedures are well tolerated with minimal morbidity. Incisions are small and placed in well-hidden areas to minimize the scar burden, seromas or hematomas are rare, and numbness following surgery is almost always temporary unless neurectomy is performed. The most common complaint is worsening of migraine headache symptoms in the acute postoperative inflammatory period, which generally improves after a few weeks.

Occasionally, successful migraine surgery may “unmask” secondary site(s) that patients describe as new sources of their migraine headaches. In these cases, patients should maintain a new headache journal and be evaluated for surgery at these secondary trigger sites. The success rate of migraine surgical decompression ranges from 79% to 90%. Factors associated with surgical failure are younger age of migraine onset, intraoperative complications, and two or fewer surgical sites. Factors associated with surgical success are surgery at a frontal or zygomaticotemporal (sensory nerve) site or at multiple trigger sites. Secondary fat injection has been shown to significantly improve or completely abate symptoms in 69% of patients with migraine headaches persisting after surgical decompression. These procedures likely improve symptoms because of the fact that trigeminal nerve branches in migraine patients are abnormal and surgical decompression or fat grafting reduces nerve irritation that may otherwise trigger a migraine headache. Successful migraine headache surgery requires working closely with neurologists or migraine headache specialists for appropriate patient diagnosis and medical management. The importance of careful patient selection and thorough analysis of long-term symptoms to determine an appropriate surgical candidate and operative plan cannot be understated.