Changes in Current Threshold During Controlled Thermocoagulation for Treatment of Trigeminal Neuralgia: a New Parameter for Judging the Result of Loss of Pain

Abstract

The substantial advantage of controlled thermocoagulation is the possibility of selective destruction of pain fibers, preserving all or most of the touch sensation. Until now, analgesia was thought to be necessary for a good result (3, 5). When we performed our first controlled thermolesion, a few patients who achieved complete pain relief experienced no sensory loss. First we found it strange and thought they would turn out as poor results, but then we heard the reports from Stockholm (1). In 1957 LEKSELL performed stereotactic irradiation of the trigeminal root and ganglion on some patients with typical trigeminal neuralgia. In two patients a follow-up examination could be made 18 years later. They had been completely free from pain without any sensory loss. In 1975 this occurrence led to a further trial. This time 23 patients were treated with the gamma unit. Most of them experienced improvement or complete pain relief after a latency of 1 day to 4–5 weeks. There was a mean follow-up of 12 months. In no case were there any significant sensory disturbances or dysesthesia or other inadvertent effects.