Sagittal Parameters Of Spine And Pelvis,Radiographic Characteristics Of Spinal Canal Cross-Section And Their Clinical Significance In Patients With Congenital Lumbar Spinal Stenosis

Purpose:①Our purpose of this study was to explore the characteristics and correlations of sagittal parameters of the spine and pelvis in patients with congenital lumbar spinal stenosis and its clinical significance.② we also explored the anatomical characteristics of the spinal canal in patients with congenital lumbar spinal stenosis.③ To explore the "normal values" and correlations of spine-pelvic sagittal plane parameters in asymptomatic healthy people in my country,to determine the factors that affect lumbar lordosis,and formulate prediction formulas.Methods:Patients admitted to the Department of Spinal Surgery,The Third Affiliated Hospital of Southern Medical University,from December 2017 to 2020 which included 40 patients with congenital lumbar spinal stenosis(congenital group)and 41 patients with acquired lumbar spinal stenosis(acquired group).The general data(sex and age)and imaging data of the patients were collected separately,including main clinical symptoms,signs,number of lesion segments,quantitative score of lesion segment location,lumbar intervertebral disc degeneration score,spine,and pelvic parameters:Sacral Slope(SS),Pelvic Tilt(PT),Pelvic Incidence(PI),LL,Thoracic Kyphosis(TK),Sagittal Vertical Axis(SVA).Anatomical parameters of spinal canal cross-section:angle of L4 ligamentum flavum,area of L4 spinal canal,AnteroPosterior diameter of the Lumbar 4 spinal canal(L4AP)(CT measurement),The VAS scores of low back pain and lower extremity pain were matched between the two groups.Relevant data of a total of 209 healthy people(normal group)without spinal disorders from 2011 to 2019 were collected,including general data(sex and age)and imaging data.The imaging data included LL,TK,SS,PI,SVA,PT,and L4AP(X-ray measurement).The correlation among those collected data in the congenital group,the acquired group,and the comprehensive groups(Contains congenital group and acquired group)were analyzed.The spine-pelvic parameters and spinal canal cross-sectional parameters were compared among the congenital group,the acquired group,and the normal group.Through the correlation and regression analysis of imaging parameters in the normal group,the prediction formula of ideal LL was established and compared with other prediction formulas.Results:There were significant differences in LL,PT,SS,and SVA among the three groups(all P<0.05).Pairwise comparison results showed that PT、SVA of the congenital group was higher than that of the acquired group(P<0.05).PT、SVA of the acquired group were higher than that of the normal group(P<0.05).LL of the congenital group was smaller than LL of the acquired group(P<0.05).LL of acquired group was smaller than the LL of the normal group(all P<0.05).SS of the congenital group was smaller than SS of the normal group(P<0.05),there were no significant difference in other parameters among the three groups(all P>0.05).In the congenital group,LL was associated with PT,SS,TK,and SVA;PT and PI were associated with SS.In the acquired group,the correlations between parameters were similar to those in the congenital group.The results of correlation analysis on the comprehensive data of the congenital group and the acquired group found that L4AP was associated with LL.In the normal group,LL was correlated with SS,TK,SVA,PI,L4AP;PI,L4AP were correlated with SS;PT was correlated with SVA,PI;SVA was correlated with PI.Accordingly,the formula 1:LL=0.547PI+0.621L4AP+10.204 and the formula 2:LL=0.558PI+21.066 can be established through regression analysis.There was no significant difference between the predicted and actual values of LL in formulas 1 and 2(P>0.05),and there were significant differences in the other formulas(all P<0.05).Compared with the acquired group,the included angle of the L4 ligamentum flavum and the area of L4 spinal canal,were smaller in the congenital group(all P<0.05).Conclusions:Compared with the acquired group,patients with congenital lumbar spinal stenosis have a more vertical spine,more pelvic involvement in compensation,and more severe sagittal imbalance.Predictive model of LL can guide connecting rod prebending during lumbar internal fixation and help restore the sagittal balance of the spine.The Angle of the ligamentum flavum in the congenital group was smaller than that in the acquired group.This anatomical feature can guide the surgeon to safely and adequately decompress the lesion segments in the congenital group.