CT guided functional stereotaxic surgery.

One of the major problems in stereotaxic surgery is to identify the brain target. Since these do not show on any of the usual radiological studies they have to be located with reference to observable structures. Initially bony landmarks were used but later either positive or negative contrast ventriculograms were found to be more accurate. Often this involves additional needling of the brain or a spinal puncture with the added mortality and morbidity associated with these procedures. We have extended the use of CT guided stereotaxic surgery to functional conditions by measuring the target position in relation to the third ventricle and the AC-PC line as seen on the unaugmented CT scan. Our experience with 27 procedures in 23 patients (9 movement disorders, 13 pain and 1 insertion of depth electrode) would indicate it is at least as accurate as other techniques. The surgical time is usually shorter and patient tolerance is better.