Retrogasserian glycerol rhizotomy and its selectivity in the treatment of trigeminal neuralgia.

In the treatment of trigeminal neuralgia, the possibility of obtaining a selective effect on different trigeminal branches by glycerol rhizotomy was studied. Transcutaneous electrical stimulation was used to quantify sensory impairment. An attempt was made to obtain a localized neurotoxic effect of the glycerol on the different trigeminal branches by keeping the patient's head in different positions during and for one hour 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 highly selective effect on the ophthalmic branch, less selective on the maxillary, and a low selective effect on the mandibular branch. However, the clinical results were equal regardless of the affected trigeminal division.