Author: Monica Zena, 4th year resident, Università degli Studi di Genova, Genova (Italy)
Migraine headache (MH) is a debilitating neurologic condition, with an important socioeconomic impact. It affects approximately 15% of the adult population and it is mostly addressed successfully with pharmacological treatment. Still, a subgroup of patient are refractory to medication (1).
Various theories have been proposed to describe MH etiology. Central neurovascular phenomena, cortical neuronal hyperexcitability, cortical spreading depression, and abnormal modulation of brain nociceptive system were all investigated as potential cause of MH (2).
In recent times, some Authors postulated that compression of extracranial sensory nerves may act as a trigger for migraine attacks (3); several “trigger sites” have thus been identified, where the nerves can be trapped by muscles, fascia, bone, bony foramina, and arteries (3):
Site I: frontal trigger. Nerves involved: supratrochlear and supraorbital nerves. Patients present frontal symptoms; the glabellar muscles or vessels may irritate the nerve
Site II: temporal trigger. Nerve involved: zygomatic temporal branch of the trigeminal nerve. Patients suffer from temporal headaches due to irritation of the nerve caused by the temporalis muscle or vessels.
Site III: rhinogenic trigger. Patients complain of paranasal and retrobulbar headaches; deviated septum, contact between the turbinates and the septum, concha bullosa, septa bullosa, and other intranasal abnormalities may irritate the trigeminal end branches.
Site IV: occipital trigger. Nerve involved: greater occipital nerve. Patients refer occipital symptoms caused by six potential irritation points as occipitalis, trapezius, and semispinalis capitis muscles, fascial bands, and the occipital artery.
Site V: temporal trigger. Nerve involved: auriculotemporal nerve. Patients complain of temporal headaches localized to the preauricular and temple region. The superficial temporal artery and fascial bands may be the cause of auriculotemporal nerve irritation.
Site VI: occipital trigger. Nerve involved: lesser occipital nerve. Patients refer occipital symptoms; trapezius and sternocleidomastoid muscles, fascial bands, and branches of the occipital artery may compress the lesser occipital nerve.
Site VII: nummular trigger. Nerve involved: not known yet. Patients refer pain to a precise point that can be localized anywhere along the midline.
Scientific data have shown involvement of different pericranial structures in migraine pain. Axonal abnormality and deregulation of the myelination process in patients with migraine headache have been documented. In addition, evidence has surfaced that the calvarial periosteum in chronic migraineurs demonstrates significantly increased expression of proinflammatory markers and decreased expression of genes that suppress inflammation and immune cell differentiation (4).
Patients who have failed medical management (because of continued pain or intolerance of medication side effects), including botulinum toxin type A, or those refractory to botulinum toxin type A after a favorable initial response, could benefit from surgery. Depending to the site, the decompression of the involved nerve is achieved through myectomy, fasciectomy, supraorbital osteotomy, and arterectomy, where indicated. Neurectomy is occasionally performed as a last resort during revision surgery in patients with recalcitrant migraine headaches. Other second-line options include corticosteroid injections, radiofrequency therapy, and peripheral nerve stimulators (5).
Fat injection has also been proven to be a safe and effective adjunctive therapy for the treatment of MH in patients who are refractory both to medical and surgical therapy. The exact mechanism of action for the therapeutic benefit of fat grafting is still unknown, but it seems related to the stem cell content of the prepared fat, that are likely involved in the helpful repair of axons and myelin and in the reduction of the final scar burden for nerve branches in migraine patients (5).
The detection of trigger sites is based on assessment of the patient’s symptoms and the site of pain onset; targeted botulinum toxin type A treatment at a primary trigger site may also be used to determine whether secondary trigger sites exist.
A portable ultrasound Doppler probe can be used to identify any vessel signal that may be contributing to nerve irritation in the area. Finally, Computed tomographic analysis is mandatory for those with retrobulbar migraine headaches to identify intranasal contact points and septonasal anomalies (1).
The success rate of surgical decompression ranges from 79 to 90 percent (5).
Trigger site–specific improvements vary from 81 to 92 percent for frontal surgery, 84 percent for temporal surgery, 45.8 to 76.2 percent for nasoseptal surgery, and 70.4 percent for occipital surgery(1).
Nevertheless, a more accurate standardization of surgical outcome parameters is required to better evaluate these encouraging data.
In conclusion, surgical decompression is a promising treatment for extra cranial chronic headache; since most of the patients are currently managed by neurologist, a multidisciplinary approach is crucial to identify patients with neuralgia that will benefit from this novel technique.
1.Bink T, Duraku LS, Ter Louw RP, Zuidam JM, Mathijssen IMJ, Driessen C. The Cutting Edge of Headache Surgery: A Systematic Review on the Value of Extracranial Surgery in the Treatment of Chronic Headache. Plast Reconstr Surg. 2019 Dec;144(6):1431-1448. doi: 10.1097/PRS.0000000000006270. PMID: 31764666.
2.Raposio E, Bertozzi N. Trigger Site Inactivation for the Surgical Therapy of Occipital Migraine and Tension-type Headache: Our Experience and Review of the Literature. Plast Reconstr Surg Glob Open. 2019 Nov 12;7(11):e2507. doi: 10.1097/GOX.0000000000002507. PMID: 31942299; PMCID: PMC6908332.
3.Gfrerer L, Guyuron B. Surgical treatment of migraine headaches. Acta Neurol Belg. 2017 Mar;117(1):27-32. doi: 10.1007/s13760-016-0731-1. Epub 2016 Dec 24. PMID: 28013487.
4.Gfrerer L, Raposio E, Ortiz R, Austen WG Jr. Surgical Treatment of Migraine Headache: Back to the Future. Plast Reconstr Surg. 2018 Oct;142(4):1036-1045. doi: 10.1097/PRS.0000000000004795. PMID: 30252818.
5.Guyuron B, Pourtaheri N. Therapeutic Role of Fat Injection in the Treatment of Recalcitrant Migraine Headaches. Plast Reconstr Surg. 2019 Mar;143(3):877-885. doi: 10.1097/PRS.0000000000005353. PMID: 30817663.