基于铅垂线观察脊柱矢状面平衡的可行性

目的探讨借助C_7铅垂线(C_7PL)来观察站立位脊柱矢状面稳定性的可行性。方法选取59名健康青少年的站立侧位脊柱全长X线片,由2位医师在医学影像存档与传输系统(PACS)工作站上通过Cobb法和C_7PL法独立测量脊柱矢状面参数,前者包括胸椎后凸角(TK)、腰椎前凸角(LL),后者包括T_6椎体与C_7PL距离(T_6PL)、L_4椎体与C_7PL距离(L_4PL)、骶骨上终板后上角与C_7PL距离(矢状面轴向距离,SVA)、股骨头中心与C_7PL距离(FPL),比较2种测量方法的重复性和相关性。结果以Cobb法测量,A医师测量的TK和 LL分别为24.1°±11.5°、51.0°±8.5°,B医师测量的TK和LL分别为28.1°±8.1°、49.4°±6.0°,2位医师测量的TK差异有统计学意义(P 0.05)并呈中度相关(r=0.662),测量的LL差异无统计学意义(P 0.05)且呈高度相关(r=0.873)。以C_7PL法测量,A医师测量的T_6PL和L_4PL分别为(27.3±19.0)mm、-(43.5±19.7)mm,B医师测量的T_6PL和L_4PL分别为(24.3±13.2)mm、-(45.5±25.9)mm,两位医师测量的T_6PL和L_4PL差异均无统计学意义(P 0.05)且呈极高度相关(r=0.905,r=0.936)。对Cobb法和C_7PL法的测量结果进行相关分析,结果显示,TK与T_6PL呈高度相关(r=0.760),LL与L_4PL呈中度负相关(r=-0.592)。对C_7PL法的测量指标进行相关分析,结果显示,T_6PL与L_4PL呈中度负相关(r=-0.655),与SVA呈低度负相关(r=-0.404),与FPL呈中度负相关(r=-0.646)。结论基于C_7PL观察脊柱矢状面曲度变化是可行的,且重复性可能更好,是整体观察脊柱-骨盆-下肢矢状面各部位相互平衡性的有效方法,值得试用。

Feasibility of measuring spinal sagittal balance based on plumb line

Objective To investigate the feasibility of measuring spinal sagittal balance based on C₇ plumb line(C₇PL) in a standing position. Methods The whole-spine lateral radiographs in a standing position were obtained from 59 asymptomatic adolescents,and were analyzed by 2 radiologists to assess the sagittal parameters of the spine in picture archiving and communication system(PACS). The measurement parameters based on Cobb method included thoracic kyphosis(TK) and lumbar lordosis(LL),and the measurement parameters based on C₇PL method included distance between the center of T₆ and C₇PL(T₆PL),the distance between the center of L₄ and C₇PL(L₄PL),the distance between the posterior superior angle of superior sacral endplate and C₇PL(sagittal vertical axis,SVA),and the distance between the center of femoral heads and C₇PL(FVL). Thereby,the repeatability and correlation of the 2 methods were analyzed. Results The Cobb method measurements indicate that TK and LL were 24.1°±11.5° and 51.0°±8.5° by radiologist A,TK and LL were 28.1°±8.1° and 49.4°±6.0°by radiologist B. There were statistical differences between the 2 radiologists in TK measurements(P<0.05),and they were moderately correlated(r=0.662). There was no statistical difference in LL measurements(P>0.05),and they were highly correlated(r=0.873). The C₇PL method measurements indicated that T₆PL and L₄PL were (27.3±19.0)mm and -(43.5±19.7)mm by radiologist A,T₆PL and L₄PL were (24.3±13.2)mm and -(45.5±25.9)mm by radiologist B. There was no statistical difference in T₆PL and L₄PL measurements(P>0.05),and they were excellently correlated(r=0.905 and 0.936). The Cobb method measurements and C₇PL method measurements were highly correlated in thoracic vertebrae(TK vs. T₆PL,r=0.760) and moderately correlated in lumbar vertebrae(LL vs. L₄PL,r=-0.592). There was a moderate negative correlation between T₆PL and L₄PL(r=-0.655),a poor negative correlation between T₆PL and SVA(r=-0.404),and a moderate negative correlation between T₆PL and FPL(r=-0.646). Conclusion It is feasible to observe the change of the sagittal spinal curvature based on C₇PL method,and this method has good repeatability. It is an effective method to observe the balance of spine-pelvis-lower limbs in the sagittal planes,being worthy to be recommended for clinical use.