Optic Nerve Sheath Diameter Detects Intracranial Hypertension in Acute Malignant Middle Cerebral Artery Infarction

Objectives: To evaluate optic nerve sheath diameter in the acute phase of patients with malignant ischemic middle cerebral artery stroke submitted or not to decompressive craniectomy surgery. Materials and Methods: Forty patients participated in the study and were evaluated bilaterally by ultrasound on admission and at 24h, 48h and 72 h after admission. Optic nerve sheath diameter values were correlated with tomographic and/or clinical criteria compatible with severe intracranial hypertension. Results: A Receiver Operating Characteristic curve was drawn for each eye, determining a cut-off value for severe intracranial hypertension in the right eye of 5.4 mm (sensitivity: 62%; specificity: 100%; AUC: 0.82) and in the left eye 5.4 mm (sensitivity: 76%; specificity: 84%; AUC: 0.77). In patients undergoing craniectomy, there was a decrease in the mean value of 1.04mm in the right eye (pre: 5.84 +/- 0.47 mm; post: 4.80 +/- 0.84 mm; p = 0.001), while in the left, it decreased around 0.86mm (pre: 5.59 +/- 0.69 mm; post: 4.73 +/- 0.74 mm; p = 0.003). Patients with fatal outcome showed a persistent high mean ocular nerve sheath diameter. Conclusions: Monitoring optic nerve sheath by ultrasound can be considered a reliable method for identifying severe intracranial hypertension in patients with large vessel occlusion, as well as for monitoring patients undergoing craniectomy. Additional studies will be necessary to include this parameter in craniectomy indication in the future.