Transorbital Ultrasonographic Measurement of Optic Nerve Sheath Diameter for Intracranial Midline Shift in Patients with Head Trauma.

Abstract

Measurement of the optic nerve sheath diameter (ONSD) by using sonography is a straightforward, noninvasive technique to detect an increased intracranial pressure, which can even be conducted at the bedside. However, the correlation between ONSD and intracranial midline shift has not been studied. The authors performed a prospective, blinded observational study in an intensive care unit. Forty-five patients were divided into groups. Of those, 19 patients had a midline shift, whereas 26 had no intracranial pathology or shift and served as control individuals. Spearman rank correlation coefficient of difference of ONSD and midline shift was 0.761 (P < 0.0005), demonstrating a significant positive correlation between patients with midline shift and control group. Despite small numbers and selection bias, this study suggests that bedside ultrasound may be useful in the diagnosis of midline intracranial shift by measurement of ONSD.