[Traumatic interhemispheric subdural hematoma--report of a case and analysis of 7 cases]

A case of traumatic interhemispheric subdural hematoma is reported and 7 cases, including ours, reported in literature are analyzed. A 43-year-old jogger hit his forehead in the traffic accident. After medical care for the wound at the near hospital, he walked to home without any neurological deficits. On the following day, he complained of headache, nausea and slight gait disturbance, so the visited us 5 days after head trauma. On the biplane computed tomograms, interhemispheric subdural hematoma was detected. A distinct avascular space in this portion was found on the right carotid angiograms. Treated conservatively with repeated computed tomography, he recovered completely well about a month after head trauma. Analyzing 7 cases, following comments were obtained; Age distribution was between 23 to 74 and all were male. The mechanism of the hematoma formation in such region remained still unclear, but seemed to be caused partially due to rotational cerebral injuries. Characteristic clinical symptom was hemiparesis, predominantly crural or crural monoparesis. This symptom was found in four of seven cases on the same side of the hematoma, that was supposed due to the compression of the contralateral blood flow the distal anterior cerebral artery. Neuroradiologically, on the angiograms, the internal branches of callosomarginal arteries turned away from the middle parallel to the pericallosal artery stayed in the middle and between them, a distinct avascular space was found. On the biplane computed tomograms, semilunar high density area was identified along the midline, bounded medially by the falx cerebri, laterally by the convex border against the brain parenchyma, inferiorly by the tentorium. Although the anteroposterior extension of the hematoma was recognized on the axial plane, the superoinferior extension, especially in relation to the tentorium, was well shown on the coronal plane. On the electroencephalogram, no characteristic findings were obtained. Abnormalities blood coagulation were found in a case. Five cases were operated on and 2 cases treated conservatively, and the outcome was good in all. The following diseases had to be differentiated: hematomas due to the rupture of peripheral anterior cerebral artery aneurysms, including traumatic ones, blood coagulopathy or medication of anticoagulants. Tumors such as parasagittal or falx meningiomas, subdural abscesses localized in the interhemisphere, infarctions of distal anterior cerebral artery.