Analysis Of Relationship Between Bone Flap Size Of Decompressive Craniectomy And Hydrocephalus After Severe Traumatic Brain Injury

ObjectivePost traumatic hydrocephalus is a common complication after decompression craniectomy of severe traumatic brain injury.Previous studies have shown that decompressive craniectomy is one of the risk factors for its occurrence.In this study,the relationship between bone flap size and hydrocephalus was analyzed by univariate analysis and multivariate analysis,and the mechanism of hydrocephalus after decompressive craniectomy was discussed,which was to provide a reference for the surgical method of patients with severe traumatic brain injury and a prediction of hydrocephalus after decompressive craniectomy.MethodThe clinical data of 1859 patients who were diagnosed with brain injury,skull defect or hydrocephalus,and treated with surgery,were analyzed retrospectively from September2016 to September 2019 at Department of Neurosurgery,Tangdu Hospital.According to the inclusion and exclusion criteria of this study,a total of 65 patients were included.The25 patients with hydrocephalus were divided into the experimental group,and the remaining 40 patients without hydrocephalus were divided into the control group.The differences of gender,age,traffic accidental injury or not,history of hypertension,injury site,intracranial hemorrhage site,midline shift distance,open injury or not,pupil changes,cerebral hernia or not,preoperative time,GCS score,operation duration,bleeding volume during operation,blood transfusion volume during operation,fluid infusion volume during operation,ICP after operation,transcalvarial herniation,the existence hygroma,hygroma site and cerebrospinal fluid infection were compared between the two groups.Variables with P<0.1 were selected as adjusting variables.The anterior-posterior line,cranio-caudal line,spherical crown diameter,and spherical crown height of the bone flap were measured,and the planar area and the spherical crown area of the bone flap were calculated respectively.The planar area,anterior-posterior line,cranio-caudal line,spherical crown area,spherical crown diameter,and spherical crown height were analysised respectively with adjusting variables using logistic regression(urivaritate logistic,enter,forward method:LR),using the occurence of hydrocephalus as dependent variable.Result1.Univariate comparison between groups:the differences of planar area,anterior-posterior line,cranio-caudal line,spherical crown area,spherical crown diameter,spherical crown height,CSF infection,traffic injury or not,bleeding volume during operation,blood transfusion volume during operation,and ICP after operation(N=50)were statistically significant(with all P<0.05).No significant differences in Gender,age,history of hypertension,injury site,intracranial hemorrhage site,midline shift distance,open injury or not,pupil change,cerebral hernia,preoperative time,GCS score,operation duration,fluid infusion volume during operation,increased ICP after operation(cutoff=15mm Hg),transcalvarial herniation,the hygroma site,and the existence hygroma were observed between the two groups(with all P>0.05).2.Logistic regression analysis:1)The results of univariate logistic regression analysis.The planar area(OR=1.130,P<0.001).When the threshold of the prediction probability p is 0.5(the same applies hereinafter),the prediction accuracy of the regression equation is 72.3%,AUC=0.822,P<0.001.Anterior-posterior line of the bone flap(OR=2.939,P=0.001).The prediction accuracy of the regression equation was 73.8%,AUC=0.784,P<0.001.The cranio-caudal line of the bone flap(OR=4.515,P=0.001).The prediction accuracy of the regression equation was 70.8%,AUC=0.755,P=0.001.Spherical crown area(OR=1.027,P=0.007),the prediction accuracy of the regression equation is 72.3%,AUC=0.738,P=0.001.Spherical crown diameter(OR=1.885,P=0.011).The prediction accuracy of the regression equation was 67.7%,AUC=0.715,P=0.004.Spherical crown height(OR=3.244,P=0.012).The prediction accuracy of the regression equation was 72.3%,AUC=0.693,P=0.009.2)The results of logistic regression adjusted by all selected adjusting variables including age,CSF infection,traffic accident injury or not,transcalvarial herniation,bleeding volume during operation and blood transfusion volume during operation.The planar area(OR=1.318,P=0.002):the prediction accuracy of the regression equation was86.2%,AUC=0.946,P<0.001.The anterior-posterior line of the bone flap(OR=7.346,P=0.002):the prediction accuracy of the regression equation was 81.5%,AUC=0.900,P<0.001.The cranio-caudal line of the bone flap(OR=7.780,P=0.002):the prediction accuracy of the regression equation was 78.5%,AUC=0.893,P<0.001.Spherical crown area(OR=1.043,P=0.003):the prediction accuracy of the regression equation is 78.5%,AUC=0.884,P<0.001.The Spherical crown diameter(OR=3.038,P=0.004):the prediction accuracy of the regression equation is 75.4%,AUC=0.873,P<0.001.The Spherical crown height(OR=4.911,P=0.013):the prediction accuracy of the regression equation is 81.5%,AUC=0.857,P<0.001.3)Stepwise logistic regression(forward LR)results Planar area(OR=1.212,P=0.001):the prediction accuracy of the regression equation is 81.5%,AUC=0.913,P<0.001.The anterior-posterior line of the bone flap(OR=5.610,P=0.001):the prediction accuracy of the regression equation was 80.0%,AUC=0.869,P<0.001.The cranio-caudal line of the bone flap(OR=6.879,P=0.001):the prediction accuracy of the regression equation was 78.5%,AUC=0.872,P<0.001.Spherical crown area(OR=1.038,P=0.003):the prediction accuracy of regression equation is 78.5%,AUC=0.837,P<0.001.Spherical crown diameter(OR=2.698,P=0.003):the prediction accuracy of the regression equation is 73.8%,AUC=0.828,P<0.001.The spherical crown height(OR=3.403,P=0.013):the prediction accuracy of the regression equation is 75.4%,AUC=0.779,P<0.001.4)The area under the ROC curve of planar area and hydrocephalus is 0.822,P<0.001.When the cut-off value is 90 cm~2,the Youden index has a maximum value of 0.63.The sensitivity is 0.88 and the specificity is 0.75 at the same time.The area under the ROC curve of spherical crown area and hydrocephalus is 0.738,P=0.001.When the cut-off value is 160cm~2,the Youden index has a maximum value of 0.52.The sensitivity is 0.64and the specificity is 0.87 at the same time.ConclusionThe planar area,anterior-posterior line,cranio-caudal line,spherical crown area,spherical crown diameter,and spherical crown height of the bone flap are all risk factors after operation for hydrocephalus in patients with severe traumatic brain injury.The results of univariate analysis and multivariate analysis are consistent.The larger the values of the above 6 variables,that is,the larger the bone flap,the higher the risk of hydrocephalus.Among these 6 indicators,the OR values of planar area and spherical crown area change little before and after the adjustment,and the OR values of the remaining 4 variables change greatly.In terms of the ability to predict hydrocephalus,the planar area performs best.When the bone flap area is used to predict hydrocephalus,the optimal cut-off values of the planar area and the spherical crown area are 90cm~2and 120cm~2,respectively.