High‐Volume Anesthetic Suboccipital Nerve Blocks for Treatment Refractory Chronic Cluster Headache With Long‐Term Efficacy Data: An Observational Case Series Study

Objective To determine the efficacy of high‐volume anesthetic suboccipital nerve blocks (HVSON) for chronic cluster headache (CCH) and to define consistency of response over long‐term use. Background There are studies showing efficacy of greater occipital and suboccipital nerve block injections for CCH and also their possible use as a preventive treatment modality. There are scant data about the long‐term efficacy of repetitive greater occipital and suboccipital nerve injections in CCH. HVSON has not been studied for CH. Methods This was an open label, observational, case series study. Patients with CCH seen at a dedicated headache clinic over a 7‐year time period and injected on at least 2 separate occasions were used for analysis. All were deemed medicinal treatment refractory. HVSON consisted of 9 mL 1% lidocaine and 1 mL triamcinolone 40 mg/mL injected on the side of CH. Results Ten CCH patients were retrospectively studied. Range of mean average response to HVSON (all patients had complete pain freedom) was 1.5–31 weeks (longest: 44 weeks in 2 patients). Only one patient did not respond; 2 patients had 1.5–2 weeks of response; the remainder had at least 4 weeks of response. The mean average duration of effect was 10.3 weeks in the responders. Five patients were injected serially for 2–4 years (30x, 17x, 15x, 10x and 3x, respectively) with a consistent response of 6 weeks, 4 weeks, 12 weeks, 4 weeks, and 31 weeks, respectively, after each injection. Response duration was very reliable per individual patient. All 5 patients felt HVSON was effective as a preventive treatment. Smoking history did not appear to alter treatment response (8/10 were chronic current smokers and 7/8 responded to HVSON). The one patient who received the most injections developed avascular necrosis of the hip; the remainder of the subjects had no adverse events. Conclusion HVSON from this open label study appears to be effective in the preventive treatment of medicinal refractory CCH and shows consistent response over long‐term use with high rates of pain freedom.