Ultrasonographic optic nerve sheath diameter as a noninvasive marker for intracranial hypotension

Background: Invasive intracranial pressure (ICP) can result in complications, pain, or even aggravate intracranial hypotension (IH) or headache in patients with IH. Objective: To investigate whether ultrasonographic measurements of optic nerve sheath diameter (ONSD) could serve as a noninvasive IH marker. Methods: Ultrasonographic ONSD was measured prior to lumbar puncture (LP) and ONSD measurements compared to LP’s opening pressure. We analyzed correlations between ONSD and ICP and determined the optimal ONSD cut-off point for IH. According to their LP on admission, patients were divided into three groups: IH group, normal ICP group, and elevated ICP group. Correlations between ONSD and ICP were analyzed using Pearson’s correlation. A receiver operating characteristic (ROC) curve was generated to determine the optimal cut-off point for IH. Results: In total, 136 subjects (75 men, 55.1% men) were included, and 1088 ONSDs were measured. The ONSD of the IH group (2.96 ± 0.15 mm) was significantly lower than that of the normal (3.59 ± 0.33 mm) and elevated ICP groups (4.90 ± 0.42 mm, p