冠状面平衡及后凸程度对强直性脊柱炎胸腰椎后凸畸形患者顶椎脊髓形态的影响

Effect of coronal balance and kyphosis severity on apical spinal cord morphology in patients with thoracolumbar kyphotic deformity secondary to ankylosing spondylitis

中文关键词:  强直性脊柱炎  胸腰椎后凸畸形  冠状面平衡  顶椎区  脊髓形态  截骨术

英文关键词:Ankylosing spondylitis  Thoracolumbar kyphosis  Coronal balance  Apical region  Spinal cord morphology  Osteotomy

中文摘要:

  【摘要】 目的：探讨强直性脊柱炎（ankylosing spondylitis，AS）胸腰椎后凸畸形患者冠状面失衡与后凸程度对顶椎区脊髓形态特征的影响。方法：回顾性分析2002年1月~2022年1月在我院接受截骨矫形手术治疗的76例AS胸腰椎后凸畸形患者的MRI，男64例，女12例，年龄21~67岁（37.1±10.9岁）。将冠状面平衡距离（coronal balanced distance，CBD）≤3.0cm的患者纳入冠状面平衡（coronal balance，CB）组（n=42），将CBD>3.0cm的患者纳入冠状面失衡（coronal imbalance，CIB）组（n=34）。再以全脊柱最大后凸角（global kyphosis，GK）将患者分为两组：GK≥80°组（n=23）和GK<80°组（n=53）。测量并比较各组术前脊柱冠状面参数：冠状面Cobb角（coronal Cobb angle）、CBD；脊柱矢状面参数：GK、胸椎后凸角（thoracic kyphosis，TK）、胸腰椎后凸角（thoracolumbar kyphosis，TLK）、腰椎前凸角（lumbar lordosis，LL）、矢状面躯干偏移（sagittal vertical axis，SVA）；脊髓形态参数：硬脊膜距离（dural distance，DD）、脊髓矢状径（spinal cord sagittal diameter，SDcord）、脊髓横径（spinal cord transverse diameter，TDcord）、脊髓压缩比（spinal cord compression ratio，CRcord）、脊髓横截面积（spinal cord transverse area，TAcord）。分析矢状面参数与脊髓形态参数的相关性。结果：CB组和CIB组患者手术年龄、性别、DD、SDcord、TDcord、CRcord、TAcord、GK、TK、LL、SVA、脊髓形态分型、截骨椎分布以及顶椎位置均无统计学差异（P>0.05），CIB组冠状位Cobb角（6.9°±0.7°）显著性大于CB组（3.2°±0.4°）（P=0.000）；CBD（5.5±0.5cm）显著性高于CB组（1.2±0.8cm）（P=0.000）。GK≥80°组DD、SDcord、CRcord和TAcord均显著性小于GK<80°组（P<0.05），TDcord显著性大于GK<80°组（P<0.05）。相关性分析结果显示，GK≥80°组DD、SDcord、TDcord、CRcord、TAcord与矢状面影像学参数均无显著相关性（P>0.05）；GK<80°组的DD和CRcord与GK呈显著性负相关（P<0.01），TDcord与GK呈显著性正相关（P<0.05）。脊髓形态参数与TLK均无显著相关性（P>0.05）。结论：冠状面失衡对AS胸腰椎后凸畸形患者顶椎区脊髓形态无显著影响。轻中度后凸（GK<80°）患者的脊髓形态与后凸角度相关，后凸进展可能动态影响脊髓形态；重度后凸（GK≥80°）患者脊髓形态趋于稳定。

英文摘要:

  【Abstract】 Objectives: To investigate the effect of coronal imbalance and kyphosis severity on the morphological characteristics of the spinal cord at apical vertebra in patients with thoracolumbar kyphotic deformity secondary to ankylosing spondylitis(AS). Methods: A retrospective analysis was performed on the T2-weighted MRIs of 76 AS patients with thoracolumbar kyphosis who underwent three-column osteotomy(3CO) between January 2002 and January 2022. There were 64 males and 12 females, aged 21-67(37.1±10.9) years old. Patients with a coronal balanced distance(CBD)≤3.0cm were assigned to the coronal balance(CB) group(n=42), while those with a CBD>3.0cm were assigned to the coronal imbalance(CIB) group(n=34). Patients were further categorized based on global kyphosis angle(GK) into: GK≥80° group(n=23) and GK<80° group(n=53). Coronal plane parameters including the coronal Cobb angle and coronal balanced distance(CBD), sagittal parameters such as GK, thoracic kyphosis(TK), thoracolumbar kyphosis(TLK), lumbar lordosis(LL), sagittal vertical axis(SVA), and spinal cord parameters consisting of dural distance(DD), spinal cord sagittal diameter(SDcord), transverse diameter(TDcord), compression ratio(CRcord), and transverse area(TAcord) were measured and compared between groups. The correlations between spinal cord parameters and sagittal spinal parameters were analyzed. Results: No significant differences were observed between CB and CIB groups in age, sex, DD, SDcord, TDcord, CRcord, TAcord, GK, TK, LL, SVA, spinal cord morphological classification, osteotomy level distribution, or apex location(P>0.05). The Cobb angle in the coronal plane was significantly greater in the　CIB group(6.9°±0.7°) than in the CB group(3.2°±0.4°) (P=0.000); The CBD was significantly greater in the CIB group(5.5±0.5cm) than in the CB group(1.2±0.8cm) (P=0.000). In the GK≥80° group, DD, SDcord, CRcord, and TAcord were significantly smaller than those in the GK<80° group(P<0.05), while TDcord was considerably larger(P<0.05). Correlation analysis revealed no significant associations between spinal cord parameters(DD, SDcord, TDcord, CRcord, TAcord) and sagittal parameters in the GK≥80° group(P>0.05). The DD and CRcord in the GK<80° group exhibited a significant negative correlation with GK(P<0.01), while TDcord showed a significant positive correlation with GK(P<0.05). None of the spinal cord morphological parameters demonstrated any correlation with TLK(P>0.05). Conclusions: Coronal imbalance has no significant impact on the spinal cord morphology in the apical vertebral region of AS patients with thoracolumbar kyphosis. In patients with mild-to-moderate kyphosis(GK<80°), spinal cord morphology was correlated with the kyphotic angle, suggesting that kyphosis progression may dynamically affect spinal cord morphology; In patients with severe kyphosis(GK≥80°), spinal cord morphology tended to be stable.