PRESSOR AND DEPRESSOR RESPONSES IN THERMOCOAGULATION OF THE TRIGEMINAL GANGLION

We have undertaken a retrospective analysis in 126 patients with trige minal neuralgia on which a free-hand percutaneous thermocoagulation of the Gasserian ganglion was performed in our department. We focused on the occurrence of intraoperative vagal reactions, i.e. significant br adycardia and changes in blood pressure during the course of the proce dure. Operative and anaesthetic records of patients who underwent the procedure were evaluated and correlated with clinical data from the pa tient's history. We observed the occurrence of vagal reactions i.e. si gnificant bradycardia (< 50/min) or syncope in 20% of patients (p < 0. 0002) during or immediately after penetration of the foramen ovale. No correlation between the operated side and the occurrence of vagal rea ctions was found. A significant rise in blood pressure levels (about 1 80 mmHg systolic) was observed in 36% of patients during thermocoagula tion. We concluded that painful stimuli arising from lesioning in the course of the trigeminal nerve reach the mid-brain and may irritate th e dorsal nucleus of the vagus nerve resulting in significant bradycard ia or cardiac synode. To prevent haemodynamic deterioration i.v. atrop ine (0.5-2 mg) should be available when advancing the needle, while an ti-hypertensive medication (Esmolol) may be needed during coagulation.