Ultrasound Greater Occipital Nerve Block at C2 Level Compared to Landmark-based Greater Occipital Nerve Block

This study will compare the analgesic benefit of a traditional landmark-guided GON block with the ultrasound-guided approach over a four week period in patients with occipital neuralgia or cervicogenic headache.

Hypothesis: A novel ultrasound-guided greater occipital nerve (GON) block at the level of C2 will result in significantly lower pain scores after 4 weeks when compared with a traditional landmark-guided approach at the superior nuchal line. The greater occipital nerve (GON) has been implicated in several conditions that prompt referral to pain medicine specialists, including occipital neuralgia and cervicogenic headache. According to the International Headache Society, a local anesthetic block of the GON can aid in the diagnosis and treatment of occipital neuralgia. Many practitioners perform GON injections using a conventional approach, relying solely on superficial bone-based anatomic landmarks to infiltrate local anesthetic and corticosteroid around the nerve at the level of the superior nuchal line. The ambiguity of these injections poses a risk of anesthetizing adjacent structures or injecting into vessels, such as the occipital artery. In an attempt to mitigate these risks and improve the efficacy of GON injections, ultrasound has been increasingly utilized. Multiple studies have demonstrated successful ultrasound-guided GON blockade at the superior nuchal line and improvement in pain scores compared to non-guided injections. The investigators' preliminary data confirms the feasibility, efficacy, and safety of an ultrasound-guided GON block technique at the level of C2, but it is not yet known whether this technique provides greater pain relief and functional outcomes compared to traditional injections.