Masakazu Suga

Prediction and evaluation of brainstem function by auditory brainstem responses in patients with uncal herniation

Serial measurements of auditory brainstem-evoked responses (BERs) were conducted in 15 patients with supratentorial mass lesions. Significant prolongation of the latency of wave V BERs, which originates in the inferior colliculus, occurred when the intracranial pressure (ICP) approached 30 mmHg. In four of five patients whose BERs were measured before pupillary changes, a significant lengthening of wave V latency was observed prior to clinical manifestation of uncal herniation. These results suggest that immediate medical or surgical decompression of ICP should be performed when ICP approaches 30 mmHg with significant prolongation of wave V latency.

Primitive Neuroectodermal Tumor with Peritoneal Metastasis through a Ventriculoperitoneal Shunt

A 13-month-old boy admitted with lethargy and hydrocephalus was found to have a right thalamic mass. Ventricular drainage was instituted, and the tumor mass was reduced by partial resection and local irradiation. A ventriculoperitoneal shunt was then placed. However, the tumor recurred 16 months later, with extensive ventricular seeding and peritoneal metastasis through the shunt tube. The child died 22 months after onset. Histological study of surgical specimens of the primary tumor and autopsy specimens of the brain and peritoneal metastatic tumors revealed poorly differentiated, small, round cells with numerous mitotic figures. In addition, autopsy specimens of the brain tumor contained areas of ependymal, oligodendroblastic, and spongioblastic differentiation. On immunohistochemical study, the tumor cells of each specimen were positive for anti-neuron specific enolase and anti-neurofilament antibodies, but negative for anti-glial fibrillary acidic protein antibodies. Electron microscopy revealed some zonulae adherens. These findings strongly suggest that the tumor originated from primitive multipotential cells capable of differentiating into ependymal, glial, and neuronal lines.

Auditory Brain Stem Responses in Uncal Herniation

The authors have reported that in patients with uncal and central herniation, lengthening of the latency and deterioration of the wave form of the auditory brain stem response (BER) wave V, which originates in the inferior colliculus, correlated well with a rostrocaudal neurological impairment after pupillary change (Nagao et al. 1983). In this study, further investigations were carried out on whether or not the changes in BER wave V are related to the development of uncal herniation before pupillary changes and to obtain objective parameters, with which to assess the effectiveness of medical decompression of ICP in the stage of uncal herniation, manifested by pupillary change (Plum and Posner 1980).

Effects of methylprednisolone on cortical neural activity, blood flow, and water content in air exposure-induced cerebral edema

The correlation of changes in cortical neuron activity with water content and local cerebral blood flow was investigated in cats with brain edema produced by air exposure. The further effect of high-dose methylprednisolone on these factors was studied. Six hours after exposure of the brain surface to air, the water content of the white matter significantly increased. The local blood flow of the cortex and white matter significantly decreased with significant suppression of cortical neural activity (direct cortical response), indicating that ischemia was responsible for neural suppression. A single, large dose of methylprednisolone (30 mg/kg, i.v.) at the beginning of air exposure significantly reduced brain edema of the cortex and white matter 12 h after air exposure and improved the local blood flow of the cortex. Methylprednisolone also caused a remarkable improvement in cortical neural activity. This steroid effect on cortical neural function may play a role in the rapid neurologic improvement observed with their use in addition to the effect on brain edema.

Management of asymptomatic unruptured aneurysms-Prospective analysis of the cases without operation.

This analysis indicates the results of a prospective study of 102 patients with 124 asymptomatic unruptured aneurysms without operation from 1993. The patients (M: 33, F: 69) were followed from 2 to 83 months (mean 38.2). The ages at diagnosis ranged from 21 to 78 years (mean 64.1) The locations were ICA: 48, MCA: 37, AcomA: 23, the vertebrobasilar artery: 9, ACA: 6 and PCA: 1. The average aneurysmal diameter was 4.3 mm, a range of 2 to 12 mm. They were followed up radiologically using MRA, MRI and 3D-CT angiography. Among the 102 patients, five had suffered subarachnoid hemorrhage (SAH) due to rupture of the aneurysms (MCA: 3, BA-SCA: 1, IC-PC: 1) The maximal diameter of the aneurysms at diagnosis ranged from 4.5 to 8 mm. The period from discovery to SAH was from 4 to 69 months and the cumulative rate of rupture of the aneurysms was 1.5 percent per year. The present study demonstrates that five asymptomatic unruptured aneurysms less than 10 mm in diameter subsequently ruptured. We ought to consider the data that unrup-tured aneurysms less than 10 mm in diameter have a very low probability of subsequent rupture published the New England Journal of Medicine (1998) very seriously.

Spinal Metastasis detected 11 Years after Initial Treatment for Pineal Germ Cell Tumor

A metastatic spinal tumor was found in a 28-year-old male 11 years after initial treatment for a pineal tumor. The original tumor had been treated by ventriculoatrial shunting, irradiation, and chemotherapy. The patient underwent laminectomy and subtotal removal of the spinal tumor, which was histologically diagnosed as germinoma. The final diagnosis of metastatic mixed germ cell tumor (mainly teratoma with a germinomatous component) of pineal origin was based on the findings of computed tomography and magnetic resonance imaging, the clinical course, tests for tumor markers, the response of the tumor to radiation therapy, and the histopathological findings. It was inferred that only the germinomatous component of the pineal mixed germ cell tumor had metastasized to the cauda equina.