Selectivity of retrogasserian glycerol rhizotomy in the treatment of trigeminal neuralgia.

The possibility of obtaining a selective effect on different trigeminal branches by glycerol rhizotomy was studied in the treatment of trigeminal neuralgia. Transcutaneous electrical stimulation was used to quantify sensory impairment. An attempt was made to direct the neurotoxic effect by maintaining the patient's head in different positions during and after glycerol injection. The amount of glycerol injected varied according to the estimated size of the trigeminal cistern and/or to which branch that was involved. The study demonstrated a good selective effect on the ophthalmic branch, less selective on the maxillary, and a poorly selective effect on the mandibular branch. However, the clinical result following glycerol rhizotomy was equal regardless of the affected trigeminal branch.