Cluster headache sufferers who become candidates for surgical treatment are those relatively rare patients who are refractory to all attempts at pharmacological relief.

Ablative surgical procedures have been directed against either the trigeminal nerve or the nervus intermedius/greater superficial petrosal (NI/GSP) pathway. Both carry nociceptive impulses from the head and face, and the NI also carries parasympathetic fibres which appear to be responsible for the autonomic concomitants of cluster headache.

Trigeminal operative procedures are not consistently helpful in chronic cluster headache, while NI section has been shown to give potentially long lasting relief but carries the potential risks of cerebellopontine angle surgery.

In eight selected cases of chronic cluster headache we have demonstrated a high early success rate for pain relief, with few complications, in the performance of NI section, combined, when indicated, with microvascular decompression of the trigeminal main sensory root. We believe that cochlear nerve monitoring helps prevent postoperative hearing impairment.

An intimate relationship between the NI and arterial loops of the anterior inferior cerebellar artery (AICA) or the internal auditory artery has been frequently observed in our chronic cluster headache patients.