Clinical Study on Chronic Subdural Hematoma

We have done clinical analysis of 92 cases with chronic subdural hematoma, admitted to our department from August 1, 1984 to July 31, 1987. The following results were obtained; 1) The ratio of male versus female was 3.6:1, and 6 cases(71.7%) were over 50 year-old age. 2) 50 cases(75.7%) in older group(over 50) had head trauma history, and 11 cases(42.3%) in younger group(under 50). 3) The major clinical symptoms and signs in older group were mental deterioration and hemiparesis, in younger group headache and vomiting. 4) The hematoma densities in CT on admission were hyperdense 1.0%, isodense 33.7%, hypodense 39.3%, and mixed 25.9%. The shapes were biconvex 45.7%, planoconvex 35.8%, and crescenteric 18.5%. 5) The operation method was either burr hole drainage, or craniotomy with membranectomy, according to patient's physical condition and CT findings. In postoperative results there was no significant difference in both.

Clinical Applications of Visual Evoked Potentials

Visual evoked potentials were elicited by flash in 29 patients with a variety of cerebral lesions and in 10 normal controls. In 12 patients with focal brain lesions, no wave form could be recorded in one side. Of the remaining 23 sides, the average P1 latency showed no difference from that of the normal controls. In 17 patients with diffuse brain lesions no wave form could be elicited in 12 sides. Average P1 latency of remaining 22 sides showed statistlcally significant difference from that of normal controls. In this study it appears that delayed P1 latencies are associated with diffuse cerebral lesions rather than with localized lesions.

Evaluation of the Effect of Myelotomy on Experimental Acute Spinal Cord Injury with Spinal Evoked Potentials

Direct spinal epidural surface of spinal evoked potentials have been made in 16 adult cats with acute spinal cord injuries produced experimentally in which myelotomy was performed in 8 cats 1 hour after the injury. The remaining 8 animals served as control. The spinal cord injury with 20gm - 20 cm was inflicted over the entire dorsal surface of the spinal cord at L2-3 interspace by Allen's weight-drop method which was improved by placing a curved steel plate anterior to the spinal cord to provide a smooth, hard surface for the receipt of posterior cord impact. Under the operating microscope, a median posterior longitudinal myelotomy approximately 10mm to 15mm in length was made at the injury site 1 hour after the injury. Animals were evaluated electrophysiologically either from preinjury state to postinjury 4 hours(control group) or from preinjury state to post myelotomy 3 hours(myelotomy group). The component waves of the spinal somatosensory evoked potentials(SSEP) of control group disappeared sequentially after the injury in the following order : N4, N3, N2, N1. In myelotomy group, N4 and N3 wave also disappeared, but N1 and N2 wave remained. The latencies of the component waves increased & its amplitudes decreased sequentially after the injury. In myelotomy group, as com-with the control group, post-traumatic latency rate increase as well as amplitude were both reduced.