Greater occipital nerve block with bupivicaine for migraine headaches: 

Background: The greater occipital nerve (GON), which derives most of its fibers from the C2 dorsal root, is the primary sensory nerve of the occipital region and upper neck. There is an anatomo-functional convergence of sensory afferents from the C2 spinal nerve and the trigeminal nerve to form the trigemino-cervical complex.

• Two recent studies looked at the utility of GON block using bupivacaine in the treatment group, compared to saline injections in the placebo group.

Summary: Both studies claim that there are statistically significant benefits to using greater occipital nerve blocks with bupivacaine in the treatment of chronic migraines. However, both studies are limited, and examine only a particular group of patients with migraines since they exclude patients with co-morbities. In addition, both studies utilized a headache diary and patient reports for clinical data, which may be prone to reporting bias. Further studies are needed prior to deeming anesthetic nerve blocks as adjunctive therapy for migraine treatment. 

     -Study#1: A prospective, randomized, multicenter, double-blind, and placebo-controlled study at 6 headache and algology centers, with the objective of assessing the efficacy of greater occipital nerve (GON) blockade at chronic migraine (CM) treatment.  84 adult patients (ages 18-65) were randomly divided into a placebo group and bupivacaine group. Over 3 months a GON blockade was administered once a week with saline in group A or bupivacaine in group B. After 4 weeks of treatment, blinding was removed; in group A, GON blockade was started using bupivacaine, while group B continued to receive bupivacaine and were followed for an additional 2 months.  The findings show that repeated GON blockade with bupivacaine significantly decreased the number of headache days, headache duration, and VAS pain scores in patients with CM compared to placebo.

      -Study #2: A double-blind, randomized, and placebo-controlled clinical trial involving thirty-six patients, with the objective of assessing the short-term clinical efficacy of GON blocks in CM.  Female patients aged 18-65 were treated either with bilateral GON block with bupivacaine 0.5% (n=18) or a sham procedure with normal saline (n=18).  Headache frequency was recorded a week after and before the procedure. The study demonstrated an absolute reduction in the number of headache calendar days with the use of GON block with bupivacaine. The study concluded that anesthetic GON block may be useful as a bridging therapy in the short term treatment of chronic migraines. 

The two studies reported minimal adverse effects, including nausea, vertigo, and pain at the injection site. No severe adverse effects were recorded. 

References:
1. Inan LE, et al. Greater occipital nerve blockade for the treatment of chronic migraine: a randomized, multicenter, double-blind, and placebo-controlled study. Acta Neurologica Scandinavica 2015: 132:270-277
2. Cuadrado M., et al. Short-term effects of greater occipital nerve blocks in chronic migraine: A double-blind, randomised, placebo-controlled clinical trial. Cephalalgia 2017: 37(9):864-872