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

OBJECTIVE: 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.

METHODS: 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.

RESULTS: 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.

CONCLUSIONS: 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.