The Prognostic Value of Optic Nerve Sheath Diameter in Patients with Subarachnoid Hemorrhage

Background: We evaluated if the optic nerve sheath diameter (ONSD) on brain computed tomography (CT) could be used to predict neurological outcomes of patients with subarachnoid hemorrhage (SAH). Methods: This was a retrospective and observational study of adult patients with SAH admitted January 2012 through June 2017. Initial brain CT was performed within 12 hours from onset of SAH. Follow-up brain CT was performed within 24 hours from treatment of ruptured aneurysm. The primary outcome was neurological status upon six months later assessed with Glasgow Outcome Scale (GOS, 1 to 5). Results: Among 223 SAH patients, survival to discharge was identified in 202 (90.6%) patients. Of these survivors, 186 (83.4%) had good neurological outcomes (GOS of 3, 4 or 5). In this study, ONSDs in the poor neurological outcome group were significantly greater than those in the good neurological outcome group (all p < 0.01). Intracranial pressure (ICP) was monitored in 21 (9.4%) patients at that time of follow-up CT scanning. There was a linear correlation between average of both ONSD and ICP in simple correlation analysis (r = 0.525, p = 0.036). In ROC curve analysis for prediction of poor neurological outcome, ONSDs had considerable predictive values (C-statistics: 0.735 to 0.812). In addition, the performance of a composite of Hunt and Hess grade and ONSD was more associated with poor neurological outcomes than the use of each marker alone. Conclusions: The ONSDs measured on CT scanning may be beneficial for predicting neurological outcomes in SAH patients.