INTRAOPERATIVE THERMAL INACTIVATION OF THE HIPPOCAMPUS IN AN EFFORT TO PREVENT GLOBAL AMNESIA AFTER TEMPORAL LOBECTOMY

In an effort to assess risk of amnesia after anterior temporal lobecto my (ATL), we conducted localized thermal inactivation (cooling) of the hippocampus with memory testing. Thirty-three ATL patients whose preo perative evaluation suggested risk for postoperative amnesia underwent hippocampal cooling. Cooling consisted of inserting a catheter in the temporal horn and irrigating it with an iced solution until a stable hippocampal temperature of similar to 20 degrees C was reached. Memory was assessed before and after cooling. In 12 of the 33 patients, memo ry testing was either aborted or suggested poor contralateral support, and the hippocampus was resected in 2 of these patients. The remainin g 21 patients showed evidence of contralateral memory support, and the hippocampus was resected in 18. No patient became amnestic, These res ults suggest that intraoperative hippocampal cooling may be useful in selected cases. However, even among many patients who could cooperate with testing, discomfort, sedation, attentional deficits, confusion, a nd anxiety made test interpretation difficult.