BACKGROUND: Hydrocephalus is a serious complication of subarachnoid hemorrhage (SAH). Obstruction of the cerebral aqueduct may cause hydrocephalus after SAH. Although various etiologic theories have been put forward, choroidal artery vasospasmerelated ependymal desquamation and subependymal basal membrane rupture as mechanisms of aqueductal stenosis have not been suggested in the literature.
METHODS: This study was conducted on 26 hybrid rabbits. Five rabbits were placed in a control group, 5 were placed in a sham group, and the remaining rabbits (n = 16) were placed in the SAH group. In the first 2 weeks, 5 animals in the SAH group died. The other 21 animals were decapitated after the 4-week follow-up period. Choroidal artery changes resulting from vasospasm, aqueduct volume, ependymal cell density, and Evans index values of brain ventricles were obtained and compared statistically.
RESULTS: Mean aqueduct volume was 1.137 mm3 ± 0.096, normal ependymal cell density was 4560/mm2 ± 745, and Evans index was 0.32 ± 0.05 in control animals (n = 5); these values were 1.247 mm3 ± 0.112, 3568/mm2 ± 612, and 0.34 ± 0.15 in sham animals (n = 5); 1.676 mm3 ± 0.123, 2923/mm2 ± 591, and 0.43 ± 0.09 in animals without aqueductal stenosis (n = 5); and 0.650 mm3 ± 0.011, 1234/mm2 ± 498, and 0.60 ± 0.18 in animals with severe aqueductal stenosis (n = 6). The choroidal vasospasm index values were 1.160 ± 0.040 in the control group, 1.150 ± 0.175 in the sham group, 1.760 ± 0.125 in the nonstenotic group, and 2.262 ± 0.160 in the stenotic group. Aqueduct volumes, ependymal cell densities, Evans index, and choroidal artery vasospasm index values were statistically significantly different between groups (P < 0.05).
CONCLUSIONS: Ependymal cell desquamation and subependymal basal membrane destruction related to choroidal artery vasospasm may lead to aqueductal stenosis and hydrocephalus after SAH.