Preventive effect of greater occipital nerve block on patients with episodic migraine: A randomized double-blind placebo-controlled clinical trial

Morphological features of the greater occipital nerve and its possible importance for interventional procedures

Being one of the most prevalent neurological symptoms, headaches are burdensome and costly. Blocks and decompression surgeries of the greater occipital nerve (GON) have been frequently used for migraine, cervicogenic headache, and occipital neuralgia which are classified under headache by International Headache Society. Knowledge of complex anatomy of GON is crucial for its decompression surgery and block. This study was performed to elucidate anatomical features of this nerve in detail. Forty-one cadavers were dissected bilaterally. According to its morphological features, GON was classified into four main types that included 18 subtypes. Moreover, potential compression points of the nerve were defined. The number of branches of the GON up to semispinalis capitis muscle and the number of its branches that were sent to this muscle were recorded. The most common variant was that the GON pierced the aponeurosis of the trapezius muscle, curved around the lower edge of the obliquus capitis inferior muscle, and was loosely attached to the obliquus capitis inferior muscle (Type 2; 61 sides, 74.4%). In the subtypes, the most common form was Type 2-A (44 sides, 53.6%), in which the GON pierced the aponeurosis of each of the trapezius muscle and fibers of semispinalis muscle at one point and there was a single crossing of the GON and occipital artery. Six potential compression points of the GON were detected. The first point was where the nerve crossed the lower border of the obliquus capitis inferior muscle. The second and third points were at its piercing of the semispinalis capitis muscle and the muscle fibers/aponeurosis of the trapezius, respectively. Fourth, fifth, and sixth compression points of GON were located where the GON and occipital artery crossed each other for the first, second, and third times, respectively. On 69 sides, 1-4 branches of the GON up to the semispinalis capitis muscle were observed (median = 1), while 1-4 branches of GON were sent to the semispinalis capitis muscle on 67 sides (median = 1). The novel anatomical findings described in this study may play a significant role in increasing the success rate of invasive interventions related with the GON.

Evaluation of the efficacy of peripheral nerve block alone in episodic and chronic migraine patients

BACKGROUND

Peripheral nerve block (PNB) is usually performed in patients with migraine who are resistant to treatment with medications.

OBJECTIVE

To compare the efficacy of PNB alone and PNB combined with prophylactic medications in migraine patients.

METHOD

The data on migraine patients who underwent PNB in our clinic between November 2019 and January 2022 were retrospectively reviewed. Blocks of the greater occipital nerve (GON), lesser occipital nerve (LON) and supraorbital nerve (SON) were performed upon admission and in the second week.

RESULTS

The study included 116 patients. While 21 out of 39 episodic migraine (EM) patients continued to use prophylactic medications, 18 were followed up with PNB alone. While 49 out of 77 chronic migraine (CM) patients continued to use prophylactic medications, 28 were followed up with PNB alone. Comparison of the admission and second-month data of the patients who only underwent PNB and those who continued the drug treatment together with PNB in both the EM and the CM group showed that the number of days with pain, number of analgesics taken and scores on the Visual Analog Scale (VAS) and the Migraine Disability Assessment (MIDAS) were significantly reduced in both groups (p < 0.01). Comparison of the second-month data of the patients followed up with PNB alone and those followed up with PNB together with prophylactic medications showed that there was no significant difference between the EM and CM patients (p > 0.05).

CONCLUSION

Bilateral GON, LON and SON block with lidocaine injection seems to be an effective treatment on its own, without the need for prophylactic medications, in both EM and CM patients during a two-month follow-up.

Greater occipital nerve blockade for the preventive treatment of chronic migraine: A randomized double-blind placebo-controlled study

BACKGROUND

Greater occipital nerve blockade for the prevention of chronic migraine has a limited evidence base. A robust randomized double-blind, placebo-controlled trial is needed.

METHODS

This double-blind, placebo-controlled, parallel-group trial, following a baseline period of four weeks, randomly assigned patients of chronic migraine 1:1 to receive four-weekly bilateral greater occipital nerve blockade with either 2 ml of 2% (40 mg) lidocaine (active group) or 2 ml of 0.9% saline (placebo) injections for 12 weeks. The primary and key secondary efficacy endpoints were a change from the baseline in the mean number of headache and migraine days and the achievement of ≥50% reduction in headache days from baseline across the weeks 9-12 respectively. Safety evaluations included the documentation and reporting of serious and other adverse events.

RESULTS

Twenty-two patients each were randomly allocated to the active and placebo group. Baseline demography and clinical characteristics were similar between the two groups. Mean headache and migraine days at baseline (±SD) were 23.4 ± 4.4 and 15.6 ± 5.7 days in the active group and 22.6 ± 5.0 and 14.6 ± 4.6 days in the placebo group respectively. The active group compared to the placebo had a significantly greater least-squares mean reduction in the number of headache and migraine days (-4.2 days [95% CI: -7.5 to -0.8; p  =  0.018] and -4.7 days [95%CI: -7.7 to -1.7; p = 0.003] respectively). 40.9% of patients in the active group achieved ≥50% reduction in headache days as compared with 9.1% of patients receiving a placebo (p = 0.024). Overall, 64 mild and transient adverse events were reported by 16 patients in the active group and 15 in the placebo. No death or serious adverse events were reported.

CONCLUSION

Four-weekly greater occipital nerve blockade with 2% lidocaine for 12 weeks was superior to placebo in decreasing the average number of headache and migraine days in patients with chronic migraine with a good tolerability profile.Clinical trial.gov no. CTRI 2020/07/026709.