Stereotactic Radiofrequency Ablation of Trigeminal Ganglion with Intraoperative CT Scans and under General Anesthesia

Introduction: Traditionally radiofrequency ablation of the trigeminal ganglion is performed using fluoroscopy and under heavy sedation. Intra-operative stimulation studies are used in order to confirm the presence of the probe tip in the appropriate division. Unfortunately, in older patients it becomes challenging to transition between heavy sedation (for probe insertion and lesion generation) and light sedation (for stimulation studies). To solve this problem, the authors describe a method in which the procedure was performed under general anesthesia and appropriate needle position was confirmed by intraoperative CT scans. Furthermore, to make the procedure more accurate a stereotactic frame was used. Methods: Eleven procedures were performed on 10 patients from 2012-2015 with a median follow-up of 21 months. The age range of the patients was 33 - 90 years (median of 55), and with a male to female ratio of 6:4. Ablations were accomplished on the 3rd division in five patients, the 2nd division in three patients, and 2nd and 3rd divisions in two patients (one of them underwent bilateral procedures). The procedures were performed under general anesthesia, using a Patil stereotactic frame on the CT table. The center of the foramen ovale was chosen as the target. The probe insertion point was approximately 2.5 cm lateral to the angle of the mouth. To place the probe tip in the 3rd division it was advanced through the foramen ovale into the trigeminal ganglion until its tip was 5 mm anterior to the clival plane. To place it in the 2nd division, it was advanced until it was in the clival plane. The probe had an exposed tip of 8 mm and heating was done at 75?C for 60 seconds. Results: Nine patients are pain-free; one patient, who had atypical facial pain did not benefit from the procedure; and one patient (with bilateral pain) has hyperesthesia on one side. Conclusion: Trigeminal ganglion ablation under general anesthesia is a good option for older patients and for those who cannot tolerate being awakened during the procedure. The stereotactic method enables easy placement of the probe and intraoperative CT scans affords confirmation of accurate probe placement.