Transcranial cerebral oximetry in endovascular treatment of carotid-cavernous fistula.

The transcranial cerebral oximeter is a reliable, low-cost, noninvasive device that provides real-time evaluation of regional brain oxygen saturation during endovascular treatment of cerebrovascular diseases. We discuss three patients with carotid-cavernous fistulae treated by endovascular balloon occlusion, each monitored continuously before, during, and after the procedure with transcranial cerebral oximetry. The cerebral oxygen saturation measured was directly related to the side of the venous drainage of the fistula, being 15-20% higher on that side. Following endovascular occlusion of the fistula, oxygen saturation gradually became equal on the two sides.