新的脊柱-骨盆矢状面测量参数：骶骨骨盆角的提出及意义

Sacral pelvic angle: a new pelvic anatomical parameter for assessing spino-pelvic sagittal balance

中文关键词:  骶骨骨盆角  脊柱  骨盆  矢状面平衡

英文关键词:Sacral pelvic angle  Spine  Pelvis  Sagittal balance

中文摘要:

  【摘要】 目的：提出一个新的脊柱-骨盆矢状面测量参数：骶骨骨盆角（sacral pelvic angle，SPA），探讨SPA与其他参数间的相关性，评估其可信度和可重复性。方法： 将脊柱侧位X线片上股骨头中点至骶骨后上角的连线（PR线）与骶骨终板垂线的夹角定义为SPA。从几何学上观测SPA与骨盆角（PA）、骶骨倾斜角（SS）之间的关系。在111例（女56例，男55例）成人志愿者的脊柱全长Ｘ线片上测量SPA及其他脊柱-骨盆矢状面相关参数，包括：SPA、胸椎后凸角（TK）、胸腰段后凸角（TLK）、腰椎前凸角（LL）、SS、骨盆倾斜角（PT）、骨盆指数（PI）、矢状面垂轴（SVA）、脊柱骶骨角（SSA）、PA、PR-S1（pelvic morphology）、总腰-骨盆前凸角（total lumbopelvic lordosis，PR-T12）。采用Pearson相关分析各参数间的相关性。从111例志愿者的脊柱全长Ｘ线片中随机抽取80例，由2位脊柱外科主治医师分别测量SPA 5次，间隔1个月后再次分别测量SPA 5次，取平均值，采用变异系数（CV）评价SPA指标稳定性，采用组内相关系数（introclass correlation coefficient，ICC）判定观测者间和两次测量间的一致性。结果：SPA=PA+SS=90°－ PR-S1。SPA与PI、PR-S1、PA、PT、SS、SSA呈显著性正相关（r=0.994，1.000，0.482，0.538，0.699，0.465，P均<0.05），与LL呈显著性负相关（r=-0.532，P<0.05）。SPA前后两次测量的CV分别为0.0023±0.02及0.0085±0.053，观测者间ICC分别为0.99，P<0.01及0.97，P<0.01，两次测量间ICC为0.99，P<0.01。结论：SPA是一个解剖学常数，SPA=PA+SS；SPA具有良好的可信度和可重复性；SPA与其他参数的相关性同PI与其他参数的相关性接近，可作为评估脊柱-骨盆矢状面平衡的参数。

英文摘要:

  【Abstract】 Objectives: To introduce a new spine-pelvic parameter, sacral pelvic angle(SPA), and to investigate the geometrical value of SPA and to evaluate its correlation, reliability and reproducibility compared with other parametres. Methods: SPA was defined as the angle between PR line and the line perpendicular to the sacral endplate. The relationship of SPA with pelvic angle(PA) and sacral slope(SS) was deduced with geometric method. Whole spine, standing radiographs of 111 Chinese adult volunteers were taken. Cobb angle and pelvic radius technique were adopted to measure the spino-pelvic sagittal parameters including SPA, thoracic kyphosis(TK), thoracolumbar kyphosis(TLK), lumbar lordosis(LL), SS, pelvic tilt(PT), pelvic incidence(PI), sagittal vertical axis(SVA), spino-sacral angle(SSA), PA, pelvic morphology(PR-S1) and total lumbopelvic lordosis(PR-T12). The correlations among all parameters were analyzed by Pearson correlation analysis. 80 radiographs were randomly chosen for SPA measurement by two independent spine surgeons for 5 times at first and another 5 times one month later. Coefficient of variation(CV) was calculated to evaluate the stability of SPA, and introclass correlation coefficient(ICC) was used to reflect the consistency of measurements by the same observer and between the two observers. Results: Geometric deduction confirmed that SPA=PA+SS=90°－PR-S1. There were statistically significant positive correlations of SPA with PI, PR-S1, PA, PT, SS, SSA(r=0.994, 1.000, 0.482, 0.538, 0.699, 0.465, P<0.05). Negative correlation was presented between SPA and LL(r=-0.532, P<0.05). CV of SPA was 0.0023±0.02 and 0.0085±0.053 for the twice mearurement. ICC between observers was 0.99(P<0.01) and 0.97(P<0.01), and ICC between twice measurements was 0.99(P<0.01). Conclusions: SPA is an anatomical parameter with good reliability and reproducibility. SPA=PA+SS. The correlation of SPA with other parametres was similar to that of PI with other parametres, which can be adopted to assess the spino-pelvic sagittal balance.