New histopathological evidence for the relationship between hydromyelia and hydrocephalus following subarachnoid hemorrhage: An experimental study

Objectives: Subarachnoid hemorrhage (SAH) is a serious pathology with a high death and morbidity rate. There can be a relationship between hydromyelia and hydrocephalus following SAH; however, this subject has not been well investigated.Materials and Methods: Twenty-four rabbits (3 +/- 0.4 years old; 4.4 +/- 0.5 kg) were used in this study. Five of them were used as the control, and five of them as the SHAM group. The remaining animals (n = 14) had been used as the study group. The central canal volume values at the C1-C2 levels, ependymal cells, numbers of central canal surfaces, and Evans index values of the lateral ventricles were assessed and compared.Results: Choroid plexus edema and increased water vesicles were observed in animals with central canal dilatation. The Evans index of the brain ventricles was 0.33 +/- 0.05, the mean volume of the central canal was 1.431 +/- 0.043 mm(3), and ependymal cells density was 5.420 +/- 879/mm(2) in the control group animals (n = 5); 0.35 +/- 0.17, 1.190 +/- 0.114 mm(3), and 4.135 +/- 612/mm(2) in the SHAM group animals (n = 5); and 0.44 +/- 0.68, 1.814 +/- 0.139 mm(3), and 2.512 +/- 11/mm(2) in the study group (n = 14). The relationship between the Evans index values, the central canal volumes, and degenerated ependymal cell densities was statistically significant (P < 0.05).Conclusions: This study showed that hydromyelia occurs following SAH-induced experimental hydrocephalus. Desquamation of ependymal cells and increased cerebrospinal fluid secretion may be responsible factors in the development of hydromyelia.