Retro-Gasserian glycerol injection in the treatment of chronic cluster headache.

Seven therapy-resistant patients with cluster headache (six of whom were chronic) were treated by percutaneous retro-Gasserian glycerol injections under general anesthesia. In four of the patients immediate and complete relief of attacks was obtained. There was a close correlation between pain relief and the degree of ophthalmic sensory loss. Quantitative estimation of thresholds for thermal perception and pain showed a good correlation to clinically evaluated sensory loss. As the analgesia waned, headaches returned, and the glycerol injections had to be repeated. Two patients were still considerably improved after 5 1/2 and nearly 3 years, respectively. In the other patients the results were less satisfactory at long-term follow-up study. Pure glycerol is highly hypertonic, and the damage of the trigeminal nerve root may be due to this property.