Ankylosing spondylitis (AS) patients with kyphosis have an abnormal spinopelvic alignment and pelvic morphology. Most studies focus on the relationship of pelvic tilt (PT) or sacral slope (SS) and deformity, and relatively few studies have addressed the relationship between pelvic incidence (PI) and kyphosis in AS patients. The purpose of this study is to analyze the correlation between pelvic incidence (PI) and the spinopelvic parameters describing local deformity or global sagittal balance in AS patients with thoracolumbar kyphosis. A total of 94 patients with AS (91 males and 3 females) and 30 controls (27 males and 3 females) were reviewed. The mean age was 36.8 years in AS patients and 34.4 years in controls. Gender ratios and mean age were similar in both group. Sagittal spinopelvic parameters, including PI, PT, SS, thoracic kyphosis (TK), thoracolumbar kyphosis (TLK), lumbar lordosis (LL), sagittal vertical axis (SVA), the first thoracic vertebra pelvic angle (TPA), spinosacral angle (SSA) and spinopelvic angle (SPA) were measured. The same spine surgeons measured all the parameters of the AS and control group. All the sagittal spinopelvic parameters were compared between the groups. The relationship between PI and other spinopelvic parameters was analyzed with Pearson correlation (r) and unary linear regression model. All the sagittal parameters were found to be significantly different between AS patients and controls. Compared with the control group, the AS patients had significantly higher PI(47.4° vs. 43.2°, P < 0.001). Correlation analysis revealed that PI in AS patients was significantly positively correlated with TPA(r = 0.533, R2 = 0.284, P < 0.001), and negatively correlated with SPA(r = − 0.504, R2 = 0.254, P < 0.001). However, no correlations were found between PI and SVA, SSA, TK, TLK or LL in AS patients. This study revealed that increasing PI was significantly correlated with more global sagittal imbalance, not with the local deformity in AS patients with thoracolumbar kyphosis.

中文翻译：

---

骨盆发病率增加与强直性脊柱炎合并胸腰椎后凸的总体矢状不平衡有关：94例观察性回顾性研究

患有后凸的强直性脊柱炎（AS）患者的脊柱骨盆排列和骨盆形态异常。大多数研究集中在骨盆倾斜（PT）或骨坡度（SS）与畸形之间的关系上，很少有研究针对AS患者的骨盆发生率（PI）和后凸畸形之间的关系。本研究的目的是分析描述胸腰椎后凸畸形的AS患者的局部畸形或整体矢状平衡的骨盆发生率（PI）与脊柱骨盆参数之间的相关性。回顾了94例AS患者（91例男性和3例女性）和30例对照（27例男性和3例女性）。AS患者的平均年龄为36.8岁，对照组为34.4岁。两组的性别比和平均年龄相似。矢状脊髓盆腔参数，包括PI，PT，SS，胸椎后凸畸形（TK），测量胸腰椎后凸（TLK），腰椎前凸（LL），矢状纵轴（SVA），第一胸椎骨盆角（TPA），脊，骨角（SSA）和脊柱骨盆角（SPA）。同一位脊柱外科医生测量了AS和对照组的所有参数。比较各组的所有矢状脊髓盂参数。使用皮尔森相关系数（r）和一元线性回归模型分析了PI与其他脊髓盆腔参数之间的关系。发现所有AS患者和对照组之间的矢状面参数均存在显着差异。与对照组相比，AS患者的PI明显升高（47.4°比43.2°，P <0.001）。相关分析表明，AS患者的PI与TPA显着正相关（r = 0.533，R2 = 0.284，P <0.001），与SPA呈负相关（r = − 0.504，R2 = 0.254，P <0.001）。但是，AS患者的PI与SVA，SSA，TK，TLK或LL之间没有相关性。这项研究表明，PI升高与更多的全局矢状不平衡显着相关，而与胸腰椎后凸畸形的AS患者的局部畸形无关。