Hu Zongshan, Vergari Claudio, Gajny Laurent, Man Gene Chi-Wai, Yeung Kwong-Hang, Liu Zhen, Lam Tsz-Ping, Zhu Zezhang, Qiu Yong, Chu Winnie Chiu-Wing, Cheng Jack Chun-Yiu, Skalli Wafa
Department of Spine Surgery, Drum Tower Hospital of Nanjing University Medical School, Nanjing, China.
Department of Orthopaedics and Traumatology, The Prince of Wales Hospital, The Chinese University of Hong Kong, Hong Kong, China.
Quant Imaging Med Surg. 2022 Apr;12(4):2311-2320. doi: 10.21037/qims-21-718.
Balanced global spinopelvic balance is important in the maintenance of the physiological alignment of all body segments above the pelvis with minimum energy expenditure. The key determinants affecting the 3D index-odontoid-hip axis (OD-HA) angle, and in particular its alterations, have not been clearly defined. The aim of this study is to identify the determinants of the 3D OD-HA angle in maintaining global spinopelvic balance in a large Chinese adult cohort of different gender and age groups.
A total of 516 asymptomatic adults were enrolled in this study. Biplanar radiographies were performed to reconstruct the subject's inter-acetabular axis and C2 odontoid process. The 3D angle formed by the vertical and the line between odontoid and mid-interacetabular axis (OD-HA angle) was computed and projected in the subject's sagittal and coronal planes. Thoracic kyphosis (TK), lumbar lordosis (LL), T1 pelvic angle (TPA) and sagittal vertical axis (SVA) were measured.
The mean values of sagittal and coronal OD-HA were -0.2°±2.5° and 0.2°±1.1°, respectively. Both sagittal and coronal OD-HA had significant correlation with age (r=0.265 and r=-0.143, P<0.01, respectively), sagittal OD-HA showed increment from 20s to 80s (-1.3° to 0.8° for female, -0.3° to 1.5° for male) and a significant difference between male and female from 20 to 69 years old. Further analysis showed that sex, weight, TK, PT, SVA, TPA and ODI were determinants of OD-HA.
3D OD-HA angle showed physiological stability with little variability from young to elderly adults, with SD of 2.45° and 1.06° in sagittal and coronal planes, respectively. OD-HA angle confirms the hypothesis that the head tends to remain above the pelvis in a small cone of stability. This study provides an analysis of the determinants of OD-HA and the reference range of the head-pelvis balance in each decade and gender based on a large-scale asymptomatic population.
全球脊柱骨盆平衡对于以最小能量消耗维持骨盆以上所有身体节段的生理对线至关重要。影响三维齿状突-髋关节轴（OD-HA）角，尤其是其改变的关键决定因素尚未明确界定。本研究的目的是在中国不同性别和年龄组的大型成年队列中确定维持全球脊柱骨盆平衡时三维OD-HA角的决定因素。
本研究共纳入516名无症状成年人。进行双平面X线摄影以重建受试者的髋臼间轴和C2齿状突。计算垂直方向与齿状突和髋臼间轴中点连线之间形成的三维角度（OD-HA角），并投影到受试者的矢状面和冠状面。测量胸椎后凸（TK）、腰椎前凸（LL）、T1骨盆角（TPA）和矢状垂直轴（SVA）。
矢状面和冠状面OD-HA的平均值分别为-0.2°±2.5°和0.2°±1.1°。矢状面和冠状面OD-HA均与年龄显著相关（r分别为0.265和r=-0.143，P<0.01），矢状面OD-HA从20多岁到80多岁呈增加趋势（女性为-1.3°至0.8°，男性为-0.3°至1.5°），且20至69岁的男性和女性之间存在显著差异。进一步分析表明，性别、体重、TK、PT、SVA、TPA和ODI是OD-HA的决定因素。
三维OD-HA角显示出从年轻人到老年人的生理稳定性，变化很小，矢状面和冠状面的标准差分别为2.45°和1.06°。OD-HA角证实了头部倾向于在一个小的稳定锥体内保持在骨盆上方的假设。本研究基于大规模无症状人群分析了OD-HA的决定因素以及每个十年和性别的头盆平衡参考范围。
