title: Uncovering a New Cause of Obstructive Hydrocephalus Following Subarachnoid Hemorrhage: Choroidal Artery Vasospasm-Related Ependymal Cell Degeneration and Aqueductal Stenosis-First Experimental Study.
abstract: 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 vasospasm-related 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 mm(3) ± 0.096, normal ependymal cell density was 4560/mm(2) ± 745, and Evans index was 0.32 ± 0.05 in control animals (n = 5); these values were 1.247 mm(3) ± 0.112, 3568/mm(2) ± 612, and 0.34 ± 0.15 in sham animals (n = 5); 1.676 mm(3) ± 0.123, 2923/mm(2) ± 591, and 0.43 ± 0.09 in animals without aqueductal stenosis (n = 5); and 0.650 mm(3) ± 0.011, 1234/mm(2) ± 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.
authors.affiliation: Erzurum Training and Research Hospital, Neurosurgery Clinic, Erzurum, Turkey.
authors.forename: Coskun
authors.initials: C
authors.lastname: Yolas
authors.affiliation: Istanbul Training and Research Hospital Clinic, Istanbul, Turkey.
authors.forename: Nuriye Guzin
authors.initials: NG
authors.lastname: Ozdemir
authors.affiliation: Department of Neurosurgery, Recep Tayyip Erdoğan University Faculty of Medicine, Rize, Turkey. Electronic address: ayhankanat@yahoo.com.
authors.forename: Ayhan
authors.initials: A
authors.lastname: Kanat
authors.affiliation: Department of Neurosurgery, Ataturk University Faculty of Medicine, Erzurum, Turkey. Electronic address: nmda11@hotmail.com.
authors.forename: Mehmet Dumlu
authors.initials: MD
authors.lastname: Aydin
authors.affiliation: Department of Anatomy, Ataturk University Faculty of Medicine, Erzurum, Turkey.
authors.forename: Papatya
authors.initials: P
authors.lastname: Keles
authors.affiliation: Department of Neurosurgery, Bahcesehir University Faculty of Medicine, Istanbul, Turkey.
authors.forename: Umit
authors.initials: U
authors.lastname: Kepoglu
authors.affiliation: Psychiatry Clinic, Bakırkoy Training and Research Hospital for Psychiatry, Neurology and Neurosurgery, Istanbul, Turkey.
authors.forename: Nazan
authors.initials: N
authors.lastname: Aydin
authors.affiliation: Department of Pathology, Ataturk University Faculty of Medicine, Erzurum, Turkey.
authors.forename: Cemal
authors.initials: C
authors.lastname: Gundogdu
mesh_terms: D000818:Animals; D002535:Cerebral Aqueduct / Q000473:pathology / Q000503:physiopathology; D002536:Cerebral Arteries / Q000473:pathology / Q000503:physiopathology; D002831:Choroid Plexus / Q000473:pathology / Q000503:physiopathology; D003251:Constriction, Pathologic / Q000209:etiology / Q000473:pathology / Q000503:physiopathology; D004195:Disease Models, Animal; D004805:Ependyma / Q000473:pathology / Q000503:physiopathology; D005500:Follow-Up Studies; D006849:Hydrocephalus / Q000209:etiology* / Q000473:pathology / Q000503:physiopathology*; D009929:Organ Size; D011817:Rabbits; D013345:Subarachnoid Hemorrhage / Q000150:complications* / Q000473:pathology / Q000503:physiopathology*; D020301:Vasospasm, Intracranial / Q000473:pathology / Q000503:physiopathology
keywords: Aqueductal stenosis; Choroidal artery vasospasm; Ependymal cell desquamation; Hydrocephalus; Subarachnoid hemorrhage