Correlation Between Intracranial Pressure And Optic Nerve Sheath Diameter Together With Rotterdam CT Score On Computed Tomography In Postoperative Patients With Moderate To Severe Traumatic Brain Injury

Objective: The purpose is to assess the relationship between optic nerve sheath diameter(ONSD)together with Rotterdam CT score measured on computed tomography(CT)and intracranial pressure(ICP)in postoperative patients with traumatic brain injury.Determine the diagnostic value for increased intracranial pressure,explore a new noninvasive method for monitoring intracranial pressure and the clinical value.Methods:(1)25 normal healthy adult volunteers who underwent orbital CT from September 2017 to October 2019 in Jiangsu Subei People's Hospital were regarded as a control group,the essential information such as gender,age,height,and weight of volunteers was collected.The optic nerve sheath diameter(ONSD)were measured at 3 mm distance from the optic globe according to the orbital thin-slice CT images,the scope of ONSD in normal people and the related factors affecting the diameter of the optic nerve sheath were analyzed.(2)Retrospective cohort study of 24 patients with moderate to severe traumatic brain injury admitted in Jiangsu Subei People's Hospital from September 2017 to October 2019,the general information was collected.The head and orbital thinslice CT were used to assess Rotterdam CT score and measure ONSD at 3mm behind the eyeball.The intracranial pressure was monitored and recorded by an intracranial pressure monitor after operation.According to the patients' intracranial pressure,they were divided into normal intracranial pressure group(ICP< 20 mm Hg)and elevated intracranial pressure group(ICP> 20 mm Hg).Linear regression was respectively used to analyze the correlation between patients' ONSD besides Rotterdam CT scores and ICP,using ROC curve to determine the optimal cut-off value of ONSD and Rotterdam CT scores to diagnose increased ICP,multiple linear regression was used to analyze the value of combined ONSD and Rotterdam CT scores in predicting increased ICP.Results:(1)There was no correlation between age,sex,and body mass index(BMI)and ONSD in 25 normal adult volunteers.The mean ONSD was 5.71±0.37 mm and the 95% confidence interval(95% CI)was 5.55-5.86 mm.(2)There was no correlation between age,gender,BMI and ONSD in 24 patients with moderate to severe head injury.The mean ONSD was 7.02±0.67 mm,the mean ICP was 19.7±9.2mm Hg,and the mean Rotterdam CT score was 4(4-5).The mean ONSD in the increased intracranial pressure group and normal intracranial pressure group were 7.55±0.57 mm and 6.64±0.45 mm,and the mean ICP were 28.6±6.2 mm Hg and 13.3±4.1 mm Hg.The value of ONSD in the increased intracranial pressure group was significantly higher than in the normal intracranial pressure group(P <0.001)and the control group(P <0.001),moreover the value of ONSD in the normal intracranial pressure group was also significantly higher than that in the control group(P <0.001).Using linear regression,the correlation between ICP and ONSD(r = 0.55,P <0.01)and Rotterdam CT score(r = 0.57,P <0.05)was significant.ROC curves was used to analyze the critical values of ONSD and Rotterdam CT score to diagnose increased ICP,the area under the curve(AUC)is 0.871 and 0.807,the cut-off values are 7.1mm and 4.5,and the sensitivity is 80 %,70%,specificity of 93%,79% respectively,they both have high diagnostic value of predicting increased ICP.When combining ONSD and Rotterdam CT scores to evaluate the diagnostic efficacy,it can be obtained that the combination of the two factors has a higher correlation with ICP,r = 0.698(P <0.05),and AUC=0.979,indicating that combination has a higher diagnostic efficiency and better effect than a single variable.Conclusion: There is a good correlation between optic nerve sheath diameter(ONSD)and intracranial pressure(ICP)in postoperative patients with moderate to severe craniocerebral injury.ONSD measured on computed tomography can predict intracranial pressure effectively,which is simple,efficient and non-invasive.Furthermore,when the optic nerve sheath diameter combined with the Rotterdam CT score,it has a better evaluation effect about the condition and the increase of intracranial pressure in patients with traumatic brain injury.Therefore,we can not only estimate the level of ICP through ONSD,but also comprehensively evaluate the level of ICP by combining the imaging manifestations of the head CT to help the clinician more effectively and easily to diagnose and treat TBI patients which has a high clinical application value.