Long-term results of radiosurgery for refractory cluster headache

Medically refractory cluster headache (CH) is a debilitating condition for which few surgical modalities have proven effective. Previous reports involving short-term follow-up of CH patients have reported modest degrees of pain relief after radiosurgery of the trigeminal nerve ipsilateral to symptom onset. With the recent success of deep brain stimulation as a surgical modality for these patients, it becomes imperative for the long-term risks and benefits of radiosurgery to be more extensively delineated. To address this issue, we present our findings from the largest retrospective series of patients undergoing radiosurgery for CH with extended follow-up periods.

Between 1997 and 2001, 10 patients with CH underwent gamma knife radiosurgery at our institution. All patients fulfilled clinical criteria for treatment, including complete resistance to pharmacotherapy (usually methysergide, verapamil, and lithium), pain primarily localized to the ophthalmic division of the trigeminal nerve, and psychological stability. The mean age at radiosurgery was 40.3 years (range, 26-62 yr), and the average CH duration was 11.3 years (range, 2-21 yr). Patients received 75 Gy to the 100% isodose line delivered to the most proximal part of the trigeminal nerve where the 50% isodose line was outside the brainstem (4-mm collimator), with a mean follow-up period of 39.7 months (range, 5-88 mo). Pain relief was defined as excellent (free of CH with minimal or no medications), good (50% reduction of CH severity and frequency with medications), fair (25% reduction of CH severity and frequency with medications), or poor (less than 25% reduction of CH severity and frequency with medications).

After radiosurgery, pain relief was poor in nine patients and fair in one patient. Six patients with poor to fair relief initially experienced excellent to good relief (range, 2 wk-2 yr after treatment) before regressing. Five patients (50%) experienced trigeminal nerve dysfunction, manifesting predominantly as facial numbness after treatment.

Although some patients may experience short-term pain relief, none had relief sustainable for longer than 2 years. The results from this series indicate that radiosurgery of the trigeminal nerve does not provide long-term pain relief for medically refractory CH.