应用计算机重建瞬时旋转轴精确评估腰椎节段稳定性及其临床意义

CLINICAL VALUE OF COMPUTER RECONSTRUCTION OF INSTANTANEOUS AXIS OF ROTATION IN ACCURATE EVALUATION OF LUMBAR SEGMENTAL STABILITY

目的应用计算机三维重建技术结合瞬时旋转轴(IAR)理论评估在体腰椎节段稳定性及其临床意义。方法选取L4-5单节段不稳并伴有半年以上下腰痛症状患者42例作为病例组,70例健康成人作为对照组。采用三维CT扫描获得受试者中立位和右旋50°位腰椎DICOM数据,应用Mimics软件重建L1～S1的三维模型;以每节段下位椎体上终板重心为坐标原点建立局部坐标系,KINZEL法计算各节段运动椎体沿IAR旋转角度、IAR到坐标原点最短距离及IAR到坐标原点最近的P点坐标。采用独立样本t检验对两组间运动椎体沿IAR旋转角度及IAR到坐标原点最短距离进行比较,组内各节段间的比较采用单因素方差分析和两两比较SNKq检验。组间P点弥散程度的差异采用卡方检验进行分析。结果正常人群L4-5节段IAR到坐标原点最短距离大于其他节段(P<0.05);L5-S1节段IAR旋转角度大于其他节段(P<0.05),IAR到坐标原点最短距离小于其他节段(P<0.05)。病例组L4-5节段IAR到坐标原点最短距离及P点弥散程度大于对照组(P<0.05),两组间IAR旋转角度比较差异无统计学意义(P>0.05)。结论计算机三维重建技术结合IAR理论既可为腰椎失稳的临床诊断和治疗提供理论依据,又可为腰椎不稳动力学机制提供精确的研究方法。

Objective To investigate the clinical value of computer three-dimensional (3D) reconstruction combined with the instantaneous axis of rotation (IAR) theory in the accurate evaluation of lumbar segmental stability.Methods A total of 42 patients with L4-5 single segmental instability and low back pain for more than half a year were enrolled as case group,and 70 healthy adults were enrolled as control group.All patients underwent 3D CT scan to obtain the DICOM data of the lumbar spine at the neutral position and the right 50° position,and Mimics software was used to reconstruct the 3D digital model of the segments L1-S1.A local coordinate system was established with the centroid of the superior endplate on each lumbar segment as the origin of the coordinate.The KINZEL’s method was used to calculate the vertebral rotation angle about IAR,the shortest distance from IAR to the origin of the coordinate,and the coordinates of P point on IAR which was the closest to the origin of the coordinate.The independent samples t -test was used for comparison of the vertebral rotation angle about IAR and the shortest distance from IAR to the origin of the coordinate between the two groups.A one-way analysis of variance was used for comparison of segments within each group,and the SNK- q test was used for pairwise comparison.The chi-square test was used to compare the dispersion degree of P point.Results In the control group,the shortest distance from IAR to the origin of the coordinate of L4-5 segments was longer than that of the other segments (P<0.05); L5-S1 segments had the largest rotation angle about IAR (P<0.05 ) and the shortest distance from IAR to the origin of the coordinate (P<0.05).Compared with the control group,the case group had a longer shortest distance from IAR to the origin of the coordinate of L4-5 segments and a higher dispersion degree of P point (P<0.05),and there was no significant difference between the two groups in vertebral rotation angle about IAR (P>0.05).Conclusion Computer 3D reconstruction technology combined with the IAR theory can provide a theoretical basis for the clinical diagnosis and treatment of lumbar instability and accurate methods for the research on the dynamic mechanism of lumbar instability.