Statistical Analysis of Chronic Subdural Hematoma in 309 Adult Cases

Abstract

Chronic subdural hematomas were analyzed statistically in 309 adult types with some comments on the dynamics of the capsule of the hematoma. On the age distribution the peak was seen in the 6th decade. 91% was male and 9% was female. History of trauma, which patients had memorized emphatically, was detected in 89%. Direction of the blow exerted sagittally in 77%. Trivial blow may sometimes had enough mechanical power to cause a shearing effect to the brain. The role of traumas in connection with the etiology should not be underestimated. Free intervals from the trauma to the onset of the disease were seen most frequently between 1-2 months. There were no pathognomonic signs and symptoms of the chronic subdural hematomas. Increased intracranial pressure, neurological deficit, and psychiatric manifestation were the prominent symptoms of all. Ataxic gait was apt to be a initial symptom and was rather frequent in the bilateral hematomas which was seen in 16%. One fourth of the total number fell into consciousness disturbance during the course. Concerning the localization hematomas were found in 88% in the frontal region and in 93% in the parietal region, which might be useful in differential diagnosis. The shape of the avascular area in the A-P view gave some keys to know the expansion and the regression of the hematomas. The content of the hematoma increases by hemorrhage from the capsule, and decreases by absorption through the capsule which was proved by using contrast medium and radioisotope. Morphological examination of the capillaries of the capsule were compatible with the increased permeability. Impairment of liver function manifested by serum protein fraction might contribute to these vascular changes. A large number of patients have spent a normal life after the operations. The removal of the capsule of the hematoma seems unneccessary in the long term follow-up study. © 1972, The Japan Neurosurgical Society. All rights reserved.