Sources of Cervicogenic Headache Among the Upper Cervical Synovial Joints

OBJECTIVES: The study sought to assess the utility of controlled diagnostic blocks in patients with probable cervicogenic headache by determining the prevalence of sources of pain among the upper and lower synovial joints of the cervical spine. METHODS: Controlled diagnostic blocks were performed in 166 consecutive patients who clinically exhibited features consistent with a diagnosis of probable cervicogenic headache. Data were collected on how often a particular source of pain could be pinpointed and how often particular diagnostic blocks provided a positive yield. RESULTS: In patients in whom headache was the dominant complaint, diagnostic blocks succeeded in establishing the source of pain in 75% of patients. The C2-3 joint was the source of pain in 62%, followed by the C1-2 (7%) and C3-4 (6%). In patients in whom headache was less severe than neck pain, blocks were successful in 67%. C2-3 was the source of pain in 42%, followed by lower cervical joints in 18% and the C3-4 joint in 7%. CONCLUSIONS: Controlled diagnostic blocks can establish the source of pain in the majority of patients presenting with probable cervicogenic headache, with C2-3 being the most common source. On the basis of pretest probability, diagnostic algorithms should commence investigations at C2-3. Second and third steps in the algorithm should differ according to whether headache is the dominant or nondominant complaint.