Comparative Effectiveness of Landmark-guided Greater Occipital Nerve (GON) Block at the Superior Nuchal Line Versus Ultrasound-guided GON Block at the Level of C2: A Randomized Clinical Trial (RCT)

Localization of the greater occipital nerve through palpation of bony landmarks: A cadaveric study

OBJECTIVE

to provide anatomic confirmation that standard methods which practitioners skilled in palpation use, can reliably identify the most likely site of emergence of the greater occipital nerve in most patients. The location and frequency of subcutaneous emergence of the greater occipital nerve and occipital artery with respect to the external occipital protuberance-mastoid line are reported.

METHODS

The external occipital protuberance and the mastoid processes were identified by palpation bilaterally on 57 body donors and the medial trisection point of a line connecting these bony landmarks was identified. A 4 cm circular dissection guide divided into 4 quadrants was centered on the trisection point and used to guide the removal of a circle of skin. The in-situ location of the nerve and artery were exposed by deep dissection within the circle. The frequency of the emergence and occurrence of the nerve and artery by quadrant were analyzed.

RESULTS

In 114 total dissections the greater occipital nerve was found to emerge within the circle 96 times (84%) and the occipital artery 100 times (88%). The nerve (90%) and artery (81%) emerged from the two inferior quadrants most of the time with no difference noted between male and female donors. The greater occipital nerve and occipital artery were found to emerge together most commonly in inferior lateral quadrant. Branches of the nerve and artery traveled together most frequently through the two lateral quadrants.

CONCLUSION

This study confirmed that the medial trisection point of the external occipital protuberance-mastoid line can be located via palpation and reliably used to pinpoint the subcutaneous emergence of the greater occipital nerve and occipital artery in most individuals. When relying on palpation alone to identify the trisection point in the clinic, infusion of nerve block inferior and lateral to this point is most likely to bathe the greater occipital nerve in anesthetic.

Comparison of greater occipital nerve blockade with radiofrequency and steroid in chronic migraine

OBJECTIVES

The study aims to retrospectively compare steroid and radiofrequency treatments for the greater occipital nerve(GON) under ultrasound guidance in chronic migraine.

METHODS

Monthly average headache attack frequency, attack duration, visual analog scale(VAS) and the number of days analgesics were taken were recorded. Under ultrasound guidance, GON block was administered once a week for a total of four sessions. In the final session, 4 mg of dexamethasone was added to the local anesthetic for the steroid group (n:26). Pulsed radiofrequency (RF) treatment was applied to the RF group (n:25) just before the last session of the GON block. The pain course in the week following the procedure monthly average headache attack frequency, attack duration, VAS and the number of days analgesics were taken in a month were compared for both groups at 1-3-6 months.

RESULTS

In the first month, a statistically significant decrease in attack frequency was observed in the RF group. However, no statistically significant differences were found between the groups in other findings at different time intervals. A significant decrease headache attack duration,VAS, and the number of days analgesics were taken in a month was observed in both treatment groups. Both treatments were found to be effective, but the effect size of the treatment was higher in the RF group compared to the steroid group.

CONCLUSION

Although the results were better in the group receiving pulsed RF treatment, except for the attack frequency in the first month, no statistically significant superiority of one treatment method over the other was determined.

Pulsed Radiofrequency Neuromodulation of the Greater Occipital Nerve for the Treatment of Headache Disorders in Adults: A Systematic Review

Background

Pulsed radiofrequency neuromodulation (PRFN) of greater occipital nerve (GON) is considered in patients with headaches failing to achieve sustained analgesic benefit from nerve blocks with local anesthetic and steroids. However, the evidence supporting this practice is unclear.

Aims

This narrative systematic review aims to explore the effectiveness and safety of GON PRFN on headaches.

Methods

Databases were searched for studies, published up to February 1, 2024, investigating PRFN of GON for adults with headaches. Abstracts and posters were excluded. Primary outcome was change in headache intensity. Secondary outcomes included effect on monthly headache frequency (MHF), mental and physical health, mood, sleep, analgesic consumption, and side-effects. Two reviewers screened and extracted data.

Results

Twenty-two papers (2 randomized controlled trials (RCT), 11 cohort, and 9 case reports/series) including 608 patients were identified. Considerable heterogeneity in terms of study design, headache diagnosis, PRF target and settings, and image-guidance was noted. PRFN settings varied (38-42°C, 40-60 V, and 150-400 Ohms). Studies demonstrated PRFN to provide significant analgesia and reduction of MHF in chronic migraine (CM) from 3 to 6 months; and significant pain relief for ON from six to ten months. Mild adverse effects were reported in 3.1% of cohort. A minority of studies reported on secondary outcomes. The quality of the evidence was low.

Conclusions

Low-quality evidence indicates an analgesic benefit from PRFN of GON for ON and CM, but its role for other headache types needs more investigation. Optimal PRFN target and settings remain unclear. High-quality RCTs are required to further explore the role of this intervention. PROSPERO ID CRD42022363234.

Managing and Preventing Migraine in the Emergency Department: A Review

Migraine is a leading cause of disability worldwide, and acute migraine attacks are a common reason for patients to seek care in the emergency department (ED). There have been recent advancements in the care of patients with migraine, specifically emerging evidence for nerve blocks and new pharmacological classes of medications like gepants and ditans. This article serves as a comprehensive review of migraine in the ED, including diagnosis and management of acute complications of migraine (eg, status migrainosus, migrainous infarct, persistent aura without infarction, and aura-triggered seizure) and use of evidence-based migraine-specific treatments in the ED. It highlights the role of migraine preventive medications and provides a framework for emergency physicians to prescribe them to eligible patients. Finally, it evaluates the evidence for nerve blocks in the treatment of migraine and introduces the possible role of gepants and ditans in the care of patients with migraine in the ED.