Predicting the outcome of the greater occipital nerve block - an observational study on migraine patients with and without musculoskeletal cervical impairment.

BACKGROUND AND OBJECTIVE

The importance of neck pain and the trigeminocervical complex in migraine is of high pathophysiological interest since a block to the greater occipital nerve is more effective for some primary headaches than others. This observational study hypothesised that the response to manual palpation of the upper cervical spine predicts the efficacy of the greater occipital nerve-block.

METHODS

We divided patients, scheduled by a neurologist to receive a greater occipital nerve-block to reduce their migraine symptoms, into three groups: Patients with no pain response to manual palpation of the neck, patients with local pain, and those with referred pain to the head. Primary outcome was the percentage change in headache frequency. Additionally, items from the quantitative sensory testing protocol were included.

RESULTS

Eighty-seven chronic migraine patients were recruited consecutively from a specialised outpatient clinic and 71 were included for analyses and stratified into the three groups: No pain (n = 11), local pain (n = 28), and referred pain to the head (n = 32). Overall, patients experienced a reduction of 1.9 headache days per month (SD 3.4,  < 0,0001). The groups differed significantly in the percentage change of headache frequency ( = 0.041) with the "no pain" group showing the largest reduction. The pressure-pain-threshold over C2 and headache on the day of the intervention influenced the outcome significantly (R 0,27,  = 0,00078). No serious adverse events occurred. Sixty-five percent of the patients had headaches during the examination. The groups did not differ regarding the distribution of patients with neck-pain in absence of migraine at baseline ( = 0.618).

CONCLUSION

Patients that were less sensitive to palpation in the cervical region and headache-free on the day of the intervention improved more after the greater occipital nerve-block.Registration: Registered at the German Clinical Trials Register (DRKS00015995).