Friedman BW et al. found GONB to be a powerful treatment for ED patients with an acute migraine, experiencing moderate or a severe headache following the use of intravenous metoclopramide. But, this investigation was discontinued before achieving a priori sample size due to the slow enrollment.

GONB might be useful for acute migraine treatment. However, there is a lack of randomized controlled rials supporting the evidence of its efficacy. The present study assumed that higher rates of headache freedom are observed when bilateral GONB with bupivacaine is carried out compared to the sham injection in patients visiting ED for continuous severe to moderate headache even after undergoing standard treatment with I.V.  Metoclopramide.

Patients who complained of a continuous severe or moderate headache for a minimum period of 1 hour or more following therapy with i.v. Metoclopramide 10mg was chosen for the randomization.

Randomized patients were given:

• Bilateral intradermal scalp injection with a total of 0.5% bupivacaine 1 mL.
• Bilateral GONB with a total of 0.5% bupivacaine 6 mL

Primary outcome: Complete freedom from headache at thirty minutes after the treatment

Secondary outcome: Sustained headache relief, known as achieving a headache level of mild or none in the ED and also maintaining a level of mild or none without the use of further headache medication for 48 hours.    

For this study, seventy-six patients were screened. Out of seventy-six, twenty-eight were registered. Sham injection was given to 15 patients while GONB was given to 13 patients for 31 months. Due to slow enrollment, the present study was ceased before having a priori sample size. In the sham arm, 0/15 (0%) of patients produced headache freedom at 30 minutes while in the GONB arm, 4/13 (31%) of patients produced headache freedom (95%CI for a difference of 31%: 6, 56%, P = 0.035). In the sham arm, 0/15 (0%) and in the GONB group, 3/13 (23%) reported sustained headache relief for 48 hours (95% CI for the difference of 23%: 0, 46%, P = 0.087). Reported side effects were comparable between the groups.

The present study concluded that treatment with GONB is useful for patents visiting ED for acute migraine, complaining of the continuous headache of moderate to severe intensity following administration of I.V. Metoclopramide. Due to slow enrollment, the study had to be stopped before achieving a priori sample size.