Association between subarachnoid hemorrhage-induced hydrocephalus and hydromyelia: pathophysiological changes developed in an experimental model

ABSTRACT

Background

Subarachnoid hemorrhage-induced hydrocephalus (SAIH) can affect the prognosis of subarachnoid hemorrhage (SAH). The relationship between hydromyelia and SAIH has been rarely investigated. This experimental model aimed to identify the pathophysiological changes developed in the SAH and elucidate the relationship between hydromyelia and SAIH.

Material and Methods

25 female rabbits were randomly divided into three groups. The SAH group (n = 15), sham group (n = 5), and control group (n = 5). In the former group, the injection of 0.5 mL/kg of autologous blood was carried out into the cisterna magna on days 0 and 2. All animals were decapitated 21 days thereafter. Histological examinations of the medulla spinalis and brain samples were performed.

Results

The mean volumes of the central channel were 1.054, 1.287, and 1.776 mm³ in the control, sham, and SAH groups, respectively (p = 0.028). The mean normal ependymal cell densities were 4.210, 3.602, and 2.923 cells/mm² in the control, sham, and SAH groups, respectively (p = 0.002). The mean ventricular Evans’ indices were 0.31, 0.34, and 0.41, in the control, sham, and SAH groups, respectively (p = 0.006). Basement membrane rupture, desquamated ependymal cells, and central channel occlusion were observed on histological examinations of the SAH group.

Conclusions

Subependymal basement membrane destruction, blood cell accumulation on it, ependymal cell desquamation, increased cerebrospinal fluid (CSF) secretion, and increased ICP in the central channel that causes hydromyelia. When these pathological changes are chronically apparent, they may reflect on CSF pathways and cause permanent SAIH. Preventing long-time SAH-induced hydromyelia is believed to reduce the high rate of treatment-requiring SAIH.

KEYWORDS:

• Subarachnoid hemorrhage-induced hydrocephalus
• pathophysiological changes
• complication
• hydrocephalus
• hydromyelia

Abbreviations

ARRIVE: Animal research: reporting in vivo experiments guidelinesi, CMI: Cisterna magna injection, CPP: Cerebral perfusion pressure, CSF: Cerebrospinal fluid, GFAP: Glial fibrillary acidic protein, H&E: Hematoxylin and eosin, ICP: Intracranial pressure, SAH: Subarachnoid hemorrhage, SAIH: Subarachnoid hemorrhage-induced hydrocephalus.

Acknowledgments

None.

Disclosure statement

No potential conflict of interest was reported by the author(s).

Additional information

Funding

The author(s) reported there is no funding associated with the work featured in this article.

Notes on contributors

Anas Abdallah

Anas Abdallah currently works as an associate professor in Neurosurgery and Spine surgery, at the Department of Neurosurgery, Istanbul Training and Research Hospital, Istanbul-Turkey. Anas does research in Neurosurgery, Neurovascular Surgery, Spine Surgery, and Neurooncology. Their most recent publication is “Factors Associated with the Recurrence of Lumbar Disk Herniation: Non-Biomechanical–Radiological and Intraoperative Factors”. Up-to-date, Anas has 50 published articles in journals indexed by the PUBMED index.