Surgical therapy of migraine: a 12-year single-center experience

In recent years, surgical therapy has taken on an increasingly decisive role in the therapeutic armamentarium of migraine. Since Guyuron’s initial popularization more than two decades ago [1], an increasing number of scientific publications have described and corroborated the surgical therapy [2‐17]. The current approach is based on the neurolysis of certain extracranial nerves, called trigger points. The most common, in our experience, are at the occipital, temporal, and frontal levels. The aim of this paper is to describe the techniques we use to treat these three specific trigger points, based on clinical experience gained over the past twelve years [18‐36].

A single-center, retrospective study was conducted on all patients who underwent surgical treatment of migraine between 2011 and 2022. Patients were asked to fill out a headache diary and complete a migraine questionnaire assessing parameters before surgery, after 3 months, and 1 year after surgery.

In the last 12 years, we have operated on 612 patients (71% females, 29% males; age range: 19–83 ys): n.266 occipital, n.248 temporal, n.98 frontal. All the patients had a diagnosis of chronic primary headache or chronic migraine confirmed by a board-certified neurologist, after failure of several attempts of different medical therapies. Patients were asked to fill out a headache diary and complete a migraine questionnaire assessing parameters before surgery, after 3 months, and 1 year after surgery. Data regarding age, sex, age at onset, migraines per month (in days), associated symptoms, severity (on a scale from 1 to 10), inability to work per month (in days), health status, history of neck trauma, and family history were collected. The Migraine Disability Assessment Scale (MIDAS) score was also used to evaluate the degree of disability for each patient [39].

After a 3-month post-operative period, the surgical procedure elicited a positive response in:

Results were substantially confirmed at the 12-month follow-up.

Complications were mild and temporary: mainly, hypoesthesia and numbness of the undermined areas, lasting from 3 weeks to 6 months. We observed the onset of secondary trigger sites in 257 (42%) patients.

After Guyuron’s initial, monumental pioneering work [40‐42], the surgical treatment of migraine has experienced an exponential diffusion both in the USA and in Europe. Actually, several migraine therapy surgeries had been described in the past. Most of these procedures were based on the section or removal of extracranial vessels [9]. In more recent years, our studies have highlighted numerous abnormalities in the vessels facing the trigger points of migraine patients [37, 38]. Interestingly, according to what has been hypothesized and described by several authors in the past [9], an extracranial vascular involvement in the etiopathogenesis of migraine therefore seems to be supported by morphological evidence. In normal arteries, the tunica intima (endothelial layer) consists of a single layer of endothelial cells surrounded by a connective tissue basement membrane with elastic fibers. The middle layer, the tunica media, is primarily composed of smooth muscle and is usually the thickest layer. During migraine surgery, we routinely tunica intima hyperplasia and internal elastic lamina fragmentation, as well as cellular alterations in the tunica media. In particular, a consistent fraction of vascular smooth muscle cells shifted from contractile versus synthetic phenotype [37, 38]. Vascular smooth muscle cells are highly specialized cells that regulate vascular tone and participate in vessel remodeling in physiological and pathological conditions. Phenotypic conversion from a contractile-quiescent to “synthetic”-active state contributes to vascular pathologies. Further research is needed to highlight the therapeutic and surgical implications of these observations. In addition, over the years, numerous trigger points have been described, including the nasal (rhinogenic) and zygomaticotemporal [43‐45]. In our experience and case studies, the three most represented trigger points were certainly those described: the occipital, the temporal, and the frontal. Regarding the treatment of the occipital trigger point, the most common approach involves (in addition to neurolysis of the occipital nerves) the exeresis of a portion of semispinalis capitis muscle and the transposition of a subcutaneous flap, while the commonly adopted surgical approach for the frontal trigger point (in addition to neurolysis of the supraorbital and the supratrochlear nerves) includes glabellar muscle group avulsion and the use of an adipose flap to cover and protect the nerves [46‐48]. Our approach, which can be defined as somewhat minimally invasive, allowed us to obtain success rates similar to the previous ones, reducing, in small part, the complexity of the surgical procedure.

The effort to identify decisive and increasingly less invasive therapeutic approaches, such as surgery, is even more important in times of COVID. During the pandemic and lockdown, migraine patients are facing an enormous problem in getting optimum care because of difficulty in access, forced social isolation, and encountering a health system that is getting rapidly overwhelmed [49]. In this perspective, given the excellent therapeutic results expected, in our opinion, the surgical approach is one of the main therapeutic resources for optimal management of this complex disease.

The described procedure is minimally invasive and highly reproducible and allows to obtain a high degree of success with a negligible rate of complications. Nevertheless, given the high percentage of occurrence of secondary trigger points, it is particularly important to warn the patient of this possibility in pre-operative visits.