Initial evaluation of the intracranial pressure in cases of traumatic brain injury without hemorrhage.

Our objective was to apply the technique of measuring diameters of optic nerve sheath (ONSD) for the intracranial pressure assessment for the cases with traumatic head injury without hemorrhage. In a retrospective study, CT data of 720 adult patients were collected and analyzed. ONSDs were measured at the point where the ophthalmic artery crosses the optic nerve (anatomical landmark) together with the eyeball transverse diameter (ETD). The ONSD/ETD index was calculated. The correlation analysis was performed with gender, age, the Glasgow Coma Scale score, and the Glasgow Outcome Score. ONSD was enlarged in 82% cases (n=591). Enlarged right/left ONSDs were 6.7±1.0/6.7±0.9mm (cut-off value˃5.5mm). ONSD/ETD ratio was 0.28±0.05 against 0.19±0.02 in healthy adults (p=0.02). We did not find correlation between ONSD/ETD ratio with initial Glasgow Coma Scale score but there was an inverse correlation between ONSD/ETD ratio and the Glasgow Outcome Score (r=−0.64). We conclude that in majority of cases with traumatic head injury without hemorrhage the ONSD is significantly enlarged indicating elevated intracranial pressure even if CT scans are negative.