Li Song, Du Chang-Zhi, Mao Sai-Hu, Shi Ben-Long, Zhu Ze-Zhang, Qiu Yong
Department of Spine Surgery, the Affiliated Drum Tower Hospital of Nanjing University Medical School, Nanjing, China.
Quant Imaging Med Surg. 2021 Jan;11(1):362-370. doi: 10.21037/qims-19-990.
The relationship between structural damage and inflammation of the spine and the sagittal imbalance in ankylosing spondylitis (AS) is not well understood. The present study aimed to investigate the correlation between structural damage and inflammation of the lumbar spine and the sagittal imbalance in AS patients with thoracolumbar kyphosis.
Forty-five AS patients with thoracolumbar kyphosis were retrospectively reviewed. Six sagittal spinal parameters, including the C7 tilt (C7T), spino-sacral angle (SSA), global kyphosis (GK), the sagittal vertical axis (SVA), thoracic kyphosis (TK), and lumbar lordosis (LL), were measured. Structural damage of the lumbar spine was assessed by the modified Stoke AS Spine Score (mSASSS) on radiographs. Lumbar spinal inflammation was evaluated by the AS spinal magnetic resonance imaging (MRI) activity (ASspiMRI-a) on MRI. Correlation analysis was performed using the paired sample -test. Multivariable linear regression models were constructed to analyze the contributions of mSASSS and ASspiMRI-a to the sagittal parameters.
The average values of the sagittal parameters C7T, SSA, GK, SVA, TK, and LL were 68.1°, 80.1°, 77.3°, 168.7 mm, 47.7°, and -0.7°, respectively. The average mSASSS and ASspiMRI-a scores were 9.8 and 10.8, respectively. Correlation analysis showed that the mSASSS and ASspiMRI-a were correlated with C7T, SSA, SVA, and LL (the Spearman correlation coefficients were -0.439, -0.390, 0.424, and 0.530 for mSASSS; -0.406, -0.402, 0.378, and 0.486 for ASspiMRI-a; P<0.05). The C7T, SSA, and SVA were significantly correlated with LL (r=-0.696, -0.779, and 0.633, respectively; P<0.05). There was a weak correlation between the mSASSS and ASspiMRI-a (β=0.299, P=0.046). The multivariable regression models indicated that the sagittal imbalance was determined to a greater extent by the mSASSS than ASspiMRI-a (the β values were -1.550 -0.649 for C7T, -1.865 -1.231 for SSA, 9.161 3.823 for SVA, and 3.128 1.717 for LL).
Both structural damage and inflammation of the lumbar spine contributed to the sagittal imbalance in AS patients with thoracolumbar kyphosis. In the late stages of AS, the sagittal imbalance was more attributable to the structural damage than the inflammation of the lumbar spine.
强直性脊柱炎（AS）中脊柱结构损伤与炎症以及矢状面失衡之间的关系尚未完全明确。本研究旨在探讨胸腰椎后凸的AS患者腰椎结构损伤与炎症和矢状面失衡之间的相关性。
回顾性分析45例胸腰椎后凸的AS患者。测量6个脊柱矢状面参数，包括C7倾斜角（C7T）、脊柱-骶骨角（SSA）、全脊柱后凸（GK）、矢状垂直轴（SVA）、胸椎后凸（TK）和腰椎前凸（LL）。通过改良斯托克强直性脊柱炎脊柱评分（mSASSS）评估腰椎的结构损伤。通过磁共振成像（MRI）上的AS脊柱磁共振成像活动（ASspiMRI-a）评估腰椎炎症。采用配对样本t检验进行相关性分析。构建多变量线性回归模型，分析mSASSS和ASspiMRI-a对矢状面参数的影响。
矢状面参数C7T、SSA、GK、SVA、TK和LL的平均值分别为68.1°、80.1°、77.3°、168.7mm、47.7°和-0.7°。mSASSS和ASspiMRI-a的平均得分分别为9.8和10.8。相关性分析显示，mSASSS和ASspiMRI-a与C7T、SSA[SVA和LL相关（mSASSS的斯皮尔曼相关系数分别为-0.439、-0.390、0.424和0.530；ASspiMRI-a的斯皮尔曼相关系数分别为-0.406、-0.402、0.378和0.486；P<0.05）。C7T、SSA和SVA与LL显著相关（r分别为-0.696、-0.779和0.633；P<0.05）。mSASSS和ASspiMRI-a之间存在弱相关性（β=¡0.299，P=0.046）。多变量回归模型表明，矢状面失衡在更大程度上由mSASSS而非ASspiMRI-a决定（C7T的β值为-1.5¡50-0.649，SSA的β值为-1.865-1.231，SVA的β值为9.161-3.823，LL的β值为¡3.128-1.717）。
腰椎的结构损伤和炎症均导致胸腰椎后凸的AS患者矢状面失衡。在AS晚期，矢状面失衡更多归因于腰椎的结构损伤而非炎症。
