Correlation of hydromyelia with subarachnoid hemorrhage-related hydrocephalus: an experimental study

Abstract

Although the central canal is an integral component of the cerebral ventricular system, central canal dilation has not been examined adequately during the progression of subarachnoid hemorrhage-related hydrocephalus (SAH-H). Central canal dilation-associated ependymal cell desquamation or subependymal membrane rupture has been rarely reported. Herein, we try to describe possible mechanisms of central canal dilation -Hydromyelia,- developing after SAH. A total of 25 New Zealand hybrid female rabbits were recruited. Five served as controls, and five received sham operations. In the remaining animals (n = 15), 0.5 mL/kg of autologous blood was injected into the cisterna magna twice on 0 and 2nd days. Five of these animals died within a few days. A total of 10 survivor animals decapitated 3 weeks later, and the brains and cervical spinal cords were histologically examined. Central canal volumes, ependymal cell numbers on the canal surfaces, and the Evans- indices of the ventricles were compared. On histological examination, central canal occlusion with desquamated ependymal cells and basement membrane rupture were evident. The mean Evans- index of the brain ventricles was 0.31, the mean central canal volume was 1.054 mm(3), and the normal ependymal cell density was 4.210/mm(2) in control animals; the respective values were 0.34, 1.287 mm(3), and 3.602/mm(2) for sham-operated animals, and 0.41, 1.776 mm(3), and 2.923/mm(2) in the study group. The differences were statistically significant (p < 0.05). Hydromyelia, an ignored complication of SAH-H, features ependymal cell desquamation, subependymal basement membrane destruction, blood cell accumulation on the subependymal cell basement membrane, and increased CSF pressure. Hydromyelia may be a significant complication following SAH.