The trauma victim with a severe closed head injury, who requires general anesthesia for emergency repair of concomitant exigent major injuries, poses a clinical dilemma. During general anesthesia and during the immediate postoperative period, the status of the patient's central nervous system cannot be clinically monitored, and emergency cerebral arteriograms and/or CAT scans are not easily obtained. Under these circumstances, delays in the diagnosis of intracranial blood accumulations frequently occur, and occult cerebral edema often goes untreated. In an attempt to avoid these management problems, we have employed intraoperative intracranial pressure (ICP) monitoring in such patients, using a subarachnoid screw. Following placement of this screw, several clinical courses may occur: 1) The patient maintains a normal pressure; thus a significant mass lesion and/or cerebral edema requiring decompression is unlikely. 2) The patient's ICP is elevated but controlled by medical management. 3) The patient's ICP cannot be controlled below 20 to 25 mm Hg using medical management, and exploratory burr holes are made. 4) If intracranial blood is encountered during placement of the ICP monitor, immediate exploratory craniotomy is indicated.