Relation of hypesthesia to the outcome of glycerol rhizolysis for trigeminal neuralgia.

The effects of percutaneous retrogasserian glycerol rhizolysis were observed in a population of 58 cases of classical trigeminal neuralgia. The follow-up period ranged from 7 to 52 months postoperatively. It was noted that 84% of the patients had immediate relief of pain. The overall recurrence rate was 29%. Based on Kaplan-Meier survival curves, the overall half-life (T1/2) of this procedure was 16 months. Although none of the patients developed anesthesia dolorosa or corneal ulceration, one group of patients developed either a clinical or subclinical persistent "minimal hypesthesia." In these there was a statistically significant difference in the T1/2 associated with this procedure (p = 0.01). This finding suggests that, contrary to the general belief, persistent hypesthesia after glycerol rhizolysis is a negative indicator of long-term success.