Alterations of facial sensitivity induced by percutaneous thermocoagulation for trigeminal neuralgia.

Sixty patients with essential trigeminal neuralgia underwent selective percutaneous thermocoagulation of the gasserian ganglion. Immediate and long-term modifications of pain and tactile facila sensitivity, recurrences of pain, and occurrences of facial paresthesias were evaluated. Pin-prick and von Frey hair tests and somatosensory-evoked potentials were used to study facila sensitivity. Patients with mild alterations of sensitivity-treated with low temperatures of coagulation (60 degrees-70 degrees C)--had a lower incidence of paresthesias, although a higher risk of recurrence. Patients with severe alterations of sensitivity--a consequence of a temperature of coagulation above 70 degrees C--had a high incidence of paresthesias and a low risk of recurrence. In our opinion, the first kind of results are better.