RADIOFREQUENCY CINGULOTOMY FOR INTRACTABLE CANCER PAIN USING STEREOTAXIS GUIDED BY MAGNETIC-RESONANCE-IMAGING

This study presents a new and simplified method of creating cingulate gyrus lesions by using stereotaxis guided by magnetic resonance imaging (MRI). Previous methods have utilized ventriculogram-guided stereotaxis requiring indirect cingulate gyrus localization and general anesthesia. With the present technique a BRW stereotactic frame was applied with the patient under local anesthesia. An MRI scan was performed using a T1 signal (TR, 600 ms; TE, 30 ms) in the coronal plane with 5-mm thick sections spaced every 6 mm. The coronal slices 24 mm posterior to the anterior tip of lateral ventricle was identified. The center of each (right and left) cingulate gyrus was identified as a target area, and appropriate coordinates were determined. Approach parameters were calculated for the right and left gyri using an azimuth of 45° and 315°, respectively, and a declination of 45°. A radiofrequency electrode was stereotactically placed so that the electrode tip was at a target point which was the center of the cingulate gyrus. A radiofrequency lesion (75°, 60 seconds) was made in each hemisphere's cingulate gyrus. Four patients with intractable terminal cancer pain have been initially treated in this manner. The lesions were well-localized on postoperative MRI scans. There have been no complications except for perilesional edema for 10 days in 1 patient (treated with longer radiofrequency settings that have subsequently been modified). Short-term pain relief in cancer patients was dramatic: morphine (intravenous 14 to 40 mg/h or oral 60 mg every 4 hours) preprocedure to oral oxycodone (1 to 2 tablets q4-6h) or oral morphine (4 to 8 mg every 4 to 6 hours) postprocedure. The use of MRI-guided stereotaxis to make cingulate gyrus lesions is an improvement that potentially allows the routine creation of these lesions as a standard cancer pain treatment. The technique is simple, uses local anesthesia, and appears to be effective and safe.