Neurophysiological monitoring of nerve branch location in semilunar ganglion radiofrequency thermocoagulation for trigeminal neuralgia

Abstract

Objective To observe the feasibility and sensitivity of electrophysiological monitoring of antidromic nerve conduction in the location of trigeminal nerve 2 (V2) or 3 (V3) in semilunar ganglion radiofrequency thermocoagulation for the treatment of trigeminal neuralgia. Methods From November 2013 to May 2014, a total of 99 patients with typical trigeminal neuralgia (139 branches, the patients with the first branch pain were excluded) treated with the semilunar ganglion radiofrequency thermocoagulation of trigeminal nerve at the Pain Diagnosis and Treatment Center, Beijing Xuanwu Hospital, Capital Medical University were enrolled retrospectively. After the puncture needle entered the foramen ovale under the guidance of CT location, sensory (50 Hz, 0.1 ms) and motor (2 Hz, 1 ms) stimulations were given. According to the complaints of patients, whether the stimulation covered the painful area of trigeminal nerve branches was made clear. The location was accurate and when the stimulation voltage was ≤0.5 V, the position of the puncture needle was correct. Multi-channel electromyograph was used to detect the nerve conduction waveforms of each branch from 0V and the threshold voltage value of the waveforms of the corresponding branches was documented. Results The complete remission rate of pain (Visual analog scale ≤3) the next day after operation was 96% (95/99). When the V2 and V3 branches were located, electromyograph recorded obvious nerve conduction waveforms in the corresponding channels in patients with V2 or V3 branch pain. When the sensory stimulation was 50 Hz, the threshold voltage value of V3 branch was 0.07±0.04 V, and V2 branch was 0.10±0.06 V. There was significant difference between both of them (P=0.002). When the motor stimulation was 2 Hz, the threshold voltage value of V3 branch was 0.09±0.04 V, and V2 branch was 0.13±0.07 V. There was significant difference between both of them (P=0.013). Conclusions Nerve antidromic conduction monitoring can be used in the location of V2 and V3 branches in the trigeminal nerve semilunar ganglion radiofrequency thermocoagulation, and the V3 branch is more sensitive. Key words: Trigeminal neuralgia; Ganglion; Radiofrequency thermo-coagulation; Nerve antidromic conduction monitoring