| Abstract: | The scanning electron microscopy (SEM) gives intersting information about the changes of the subarachnoid space. In this study, specimens from 16 patients (one during surgery and others at autopsy) were examined by SEM: 11 cases of subarachnoid hemorrhage, 2 of posterior fossa brain tumor operated and 3 of control cases without CNS diseases. In cases of subarachnoid hemorrhage, there seemed to be three stages of the obstruction in the subarachnoid space: a) obstruction by blood clots mainly consisted of red blood cells, b) obstruction by subarachnoid fibrosis with thickening of arachnoid, c) obstruction by arachnoid adhesion obliterating subarachnoid space. Specimens from parietal parasagittal area, lateral cerebral fissure and temporal base on both sides were systematically examined by SEM, and the degree of the obstructive changes of the subarachnoid space were classified into five grades: 0) no changes 1) minimal changes--slight thickening of arachnoid and perivascular fibrosis in subarachnoid space 2) moderate changes--thickening of arachnoid and fibrosis in subarachnoid space with patent meshwork 3) severe obstruction of subarachnoid meshwork 4) complete obstruction of subarachnoid space--no space for CSF circulation. We found high incidence of communicating hydrocephalus after SAH in those cases in which epicortical CSF circulation was obstructed more than grade 3 in the parasagittal area bilaterally. |
