[Evaluation of computerized tomography-guided stereotactic evacuation of putaminal hematomas by somatosensory evoked potentials].

Computerized tomography (CT) guided stereotactic evacuation of intracerebral hematomas is effective and little invasive treatment at subacute or chronic stage. Somatosensory evoked potentials (SEPs) of 23 patients with putaminal hemorrhage whose stereotactic evacuations were performed from day 4 to day 24 are studied about surgical result and CT findings. As for SEP, N20 which is thought to be generated in the thalamus or in the primary parietal area receiving direct projections from the thalamus is used for comparison with functional recovery. Among 12 patients whose N20s before the evacuation showed normal, 9 had good recovery of their hemiplegia. Motor recovery tended to begin quickly after the evacuation and the evacuation of hematomas were thought to make better result than conservative treatment. CT findings of 9 patients with good recovery revealed that the hematomas didn't invade to the internal capsule or invaded to the posterior part of the posterior limb alone. Among 3 patients whose N20s before the evacuation were not distinct and those after the evacuation were normal, 2 had good recovery of their hemiplegia. As those hematomas were relatively large but located laterally, the internal capsule was seem to be not invaded but only compressed. Among 8 patients whose N20s were not distinct both before and after the evacuation, 7 could not get the recovery of their hemiplegia. CT findings of them revealed that the hematomas were large or invaded toward the internal capsule and thalamus. From this study N20s of SEPs are thought to be useful to the decision of indication and the prediction of the functional prognosis about stereotactic evacuation of putaminal hemorrhage.