Repeated Bilateral Greater Occipital Nerve Blockade in Chronic Migraine and Chronic Tension-Type Headache

This multicenter, randomized, double-blind, placebo-controlled clinical trial aims to evaluate the efficacy of repeated bilateral greater occipital nerve (GON) blockade in patients with chronic migraine and chronic tension-type headache. Greater occipital nerve blockade has been widely used as an interventional treatment for chronic headache disorders; however, evidence regarding its differential efficacy across chronic headache phenotypes remains limited. Participants diagnosed with chronic migraine or chronic tension-type headache according to the International Headache Society criteria were randomized to receive bilateral GON blockade with 0.5% bupivacaine or placebo (0.9% saline). Injections were administered weekly during the first month and monthly during the following two months, resulting in a total of six injections over a three-month treatment period. The primary outcome measure is the change in monthly headache frequency from baseline to Month 1. Secondary outcomes include changes in headache intensity, headache duration, disability scores, and other clinical headache parameters during follow-up.