Spine Surgery Department, St. Franziskus-Hospital, Cologne, Germany;
Research Office, Biostatistics, Paracelsus Medical University, Salzburg, Austria; and.
J Neurosurg Spine. 2015 Jul;23(1):16-23. doi: 10.3171/2014.11.SPINE14368. Epub 2015 Apr 24.
Sagittal malalignment of the cervical spine has been associated with worsened postsurgical outcomes. For better operative planning of fusion and alignment restoration, improved knowledge of ideal fusion angles and interdependences between upper and lower cervical spine alignment is needed. Because spinal and spinopelvic parameters might play a role in cervical sagittal alignment, their associations should be studied in depth.
The authors retrospectively analyzed digital lateral standing cervical radiographs of 145 patients (34 asymptomatic, 74 symptomatic; 37 surgically treated), including full-standing radiographs obtained in 45 of these patients. Sagittal measurements were as follows: C2-7, occiput (Oc)-C2, C1-2 Cobb angles, and C-7 slope (the angle between the horizontal line and the superior endplate of C-7), as well as T4-12 and L1-S1 Cobb angles, sacral slope, pelvic incidence, and C-7 sagittal vertical axis (SVA). A correlation analysis was performed, and linear regression models were developed.
Statistical analyses revealed significant correlations between C2-7 and Oc-C2 (r = -0.4, p < 0.01), Oc-C2 (r = -0.3, p < 0.01), and C1-2 angle (r = -0.3, p < 0.01). C-7 slope was significantly correlated with C2-7 (r = -0.5, p < 0.01) and with Oc-C2 angle (r = 0.2, p = 0.02). Total cervical (Oc-C7) lordosis was 30.2° and did not differ significantly among asymptomatic, symptomatic, and surgically treated patients. Correlations between C2-7 and Oc-C2 alignment were stronger in asymptomatic patients (r = -0.5, p < 0.01) and surgically treated patients (r = -0.5, p < 0.01) than in symptomatic patients (r = -0.3, p = 0.01), but the between-group difference was not significant (p > 0.1). Comparing cervical and spinopelvic alignment revealed a significant correlation between sacral slope and C-7 slope (r = -0.3, p = 0.04) and C2-7 (r = 0.4, p < 0.01). The C-7 SVA correlated significantly with the C-7 slope (r = -0.4, p < 0.01). The interdependences were stronger within the occipitocervical parameters than between the cervical and remaining spinal parameters.
Significant correlations between the upper and lower cervical spine exist, confirming the existence of inherent compensatory mechanisms to maintain overall balance; no significant differences were found among asymptomatic, symptomatic, and surgically treated patients. The C-7 slope is a useful marker of overall sagittal alignment, acting as a link between the occipitocervical and thoracolumbar spine.
颈椎矢状位失平衡与术后转归恶化相关。为了更好地规划融合手术和恢复对线，需要深入了解理想融合角度以及颈椎上、下部分对线之间的相互依存关系。由于脊柱和骨盆参数可能在颈椎矢状位对线中发挥作用，因此应深入研究它们之间的关联。
作者回顾性分析了 145 例患者（34 例无症状，74 例有症状；37 例接受手术治疗）的数字侧位站立颈椎 X 线片，其中 45 例患者获得了完整的站立位 X 线片。测量的矢状位参数包括：C2-7、枕骨（Occ）-C2、C1-2 Cobb 角和 C-7 斜率（C-7 上终板与水平线之间的夹角），以及 T4-12 和 L1-S1 Cobb 角、骶骨斜率、骨盆入射角和 C-7 矢状垂直轴（SVA）。进行了相关性分析，并建立了线性回归模型。
统计分析显示，C2-7 与 Oc-C2（r = -0.4，p < 0.01）、Oc-C2（r = -0.3，p < 0.01）和 C1-2 角（r = -0.3，p < 0.01）之间存在显著相关性。C-7 斜率与 C2-7（r = -0.5，p < 0.01）和 Oc-C2 角（r = 0.2，p = 0.02）呈显著相关性。总颈椎（Oc-C7）前凸为 30.2°，无症状、有症状和接受手术治疗的患者之间无显著差异。无症状患者（r = -0.5，p < 0.01）和接受手术治疗的患者（r = -0.5，p < 0.01）的 C2-7 和 Oc-C2 对线之间的相关性强于有症状患者（r = -0.3，p = 0.01），但组间差异无统计学意义（p > 0.1）。比较颈椎和骨盆矢状位参数发现，骶骨斜率与 C-7 斜率（r = -0.3，p = 0.04）和 C2-7（r = 0.4，p < 0.01）之间存在显著相关性。C-7 SVA 与 C-7 斜率（r = -0.4，p < 0.01）显著相关。枕颈参数之间的相关性强于颈椎与其余脊柱参数之间的相关性。
颈椎上、下部分之间存在显著相关性，证实了维持整体平衡的固有代偿机制的存在；无症状、有症状和接受手术治疗的患者之间无显著差异。C-7 斜率是整体矢状位对线的有用标志物，是枕颈和胸腰椎之间的联系。
