Analysis Of Risk Factors Of Neurological Deficits In Burst Fracture Of The First Lumbar Vertebra

Objective:The purpose of this study is to find out the correlation between imaging findings and neurological deficits in L1 burst fracture.Methods:A retrospective analysis was made on 61 patients with L1 burst fracture between June 2015 and June 2019.Imaging data of all patients,including the anterior and posterior height of vertebral body,interpedicular distance(IPD),local kyphosis(LK),mid-sagittal canal diameter(MSD)and the location of the conus medullaris were collected.According to the ASIA score scale,all the included data were divided into 5 grades A?E.Anterior and posterior height compression ratio of vertebral body,TD,LK,IPD and CC parameters were collected,and the correlation between the parameters and the degree of neurological injury was evaluated by Spearman correlation analysis.Meaningful parameters are combined for prediction.The diagnostic effectiveness of each combination was compared,and the best diagnostic combination was determined to carry out parallel and serial diagnostic tests.According to the results of MRI examination,the patients were divided into high position group(middle cross section or above of L1)and low position group(below middle cross section of L1).t-test was used to evaluate the correlation between the location of conus medullaris and the degree of neurological injuryResults:There was no significant correlation between the anterior and posterior height compression ratio of vertebral body and LK(P>0.05).However,there is significant relationship between TD(?=0.574,P<0.001),IPD(y=0.408,P=0.001),CC(?=0.648,P<0.001)and the degree of spinal cord neurological injury.The sensitivity(TD:77.40%;IPD:74.19%;CC:70.97%),specificity(TD:70.00%;IPD:56.67%;CC:83.33%)and cut-off point(TD:2.55 mm;IPD:21.80%;CC:39.00%)of the above parameters were determined by ROC curve,and the diagnostic value of each parameter was statistically different(P<0.05).The sensitivity and specificity(TD+IPD:77.42%;TD+CC:80.65%;IPD+CC:87.10%)of the three parameters combined with each other,and there was no significant difference in diagnostic efficacy among the three combinations(P>0.05).Parallel and serial diagnostic tests on the combined parameters of IPD+TD and IPD+CC were found to have higher sensitivity and specificity,in which the sensitivity of IPD>21.80%or TD>2.55 mm was 93.55%,and the sensitivity of CC>21.80%or CC>39.00%was 93.55%.Patients with low conus medullaris are more likely to suffer nerve damage than patients with high conus medullaris(P<0.05).Conclusion:There was no significant correlation between the compression ratio of anterior and posterior edge of vertebral body and LK parameters and the degree of nerve injury,But IPD,TD and CC were significantly correlated with the degree of nerve injury.The cutoff points of IPD>21.80%,TD>2.55 mm and CC>39.00%have certain predictive value in evaluating whether the patient's nerve is damaged,and the diagnostic efficacy is CC?TD?IPD.There is a strong linear correlation between IPD,TD and CC.The predictive value of the combination of the three parameters is higher than that of a single parameter,which can further reduce the occurrence of missed diagnosis and misdiagnosis,and there is no statistical difference in the diagnostic effectiveness of each combination.Without the support of CT and MRI examination,IPD>21.80%or TD>2.55 mm can be used as the prediction index of primary screening nerve injury;if there is no support of MRI examination,IPD>21.80%or CC>39.00%can be used as the primary screening index.Patients with low conus medullaris are more likely to suffer nerve damage than patients with high conus medullaris.