Xu Yanjie, Fan Changsheng, Li Dongyue, Qiu Yong, Liu Zhen, Zhu Zezhang
Division of Spine Surgery, Department of Orthopedic Surgery, Drum Tower Hospital of Nanjing University Medical School, Nanjing, China.
Division of Spine Surgery, Department of Orthopedic Surgery, Drum Tower Hospital Clinical College of Nanjing Medical University, Nanjing, China.
J Orthop Surg Res. 2025 Jul 18;20(1):675. doi: 10.1186/s13018-025-06103-5.
Pelvic compensation, as quantified by the pelvic tilt (PT), has been identified as a crucial compensatory mechanism in patients with adult spinal deformity (ASD). However, it remains uncertain whether PT has important roles in predicting the occurrence of proximal junctional kyphosis (PJK). Therefore, the purpose of this study is to analyze the influence of pelvic compensation, specifically PT, on the development of PJK in ASD patients following the second sacral alar-iliac (S2AI) fixation.
A total of 163 patients with ASD who underwent surgical treatment with S2AI fixation were retrospectively reviewed. According to the median value of pelvic tilt ratio (PTr) measured at baseline, patients were divided into the high PT group (PTr ≥ 0.6) and the low PT group (PTr < 0.6). Patients were further subdivided according to the degree of PT correction with the age-adjusted equation: PT = (age- 55) / 3 + 20. Patients who met the exact ± 10-year threshold for age-adjusted targets were assigned to group I (ideal correction). Patients whose correction deviated by more than 10 years above or below their age were classified into group U (undercorrection) and group O (overcorrection), respectively. Demographic, surgical, and radiographic parameters and the rates of PJK were compared between groups.
Patients in the high PT group had significantly lower baseline TK, LL, as well as greater PI-LL and T1PA compared with the low PT group (all P < 0.05). Notably, the incidence of PJK was significantly higher in the high PT group compared to the low PT group (43.2% vs. 12.2%, χ²=19.612, P < 0.001). Further stratification by age-adjusted PT correction revealed significant differences in radiographic parameters across the subsets within both the low and high PT groups. In addition, among patients in the high PT group, the incidence of PJK was significantly lower in the overcorrected PT group (11/38, 28.9%) than under- (14/23, 60.9%) and ideal correction (10/20, 50%) of PT (χ²=6.449, P = 0.040).
Patients in the high PT group, representing those with exhausted pelvic compensatory capacity, had a significantly higher risk of PJK compared to the low PT group. Further stratification by postoperative age-adjusted PT correction revealed that, within the high PT group, overcorrection of PT was associated with the lowest incidence of PJK, while undercorrection presented the highest risk. These findings suggest that patients with substantial baseline pelvic decompensation may benefit from a more aggressive PT correction to provide a stable foundation for spinal constructs and improve clinical outcomes in ASD surgery.
骨盆倾斜度（PT）所量化的骨盆代偿，已被确定为成人脊柱畸形（ASD）患者的关键代偿机制。然而，PT在预测近端交界性后凸（PJK）发生方面是否具有重要作用仍不确定。因此，本研究的目的是分析骨盆代偿，特别是PT，对ASD患者在第二骶骨翼-髂骨（S2AI）固定术后PJK发生发展的影响。
回顾性分析163例行S2AI固定手术治疗的ASD患者。根据基线测量的骨盆倾斜度比值（PTr）的中位数，将患者分为高PT组（PTr≥0.6）和低PT组（PTr<0.6）。根据年龄校正公式PT =（年龄 - 55）/ 3 + 20进一步细分患者。达到年龄校正目标精确±10年阈值的患者被分配到I组（理想矫正）。矫正偏离其年龄上下超过10年的患者分别分为U组（矫正不足）和O组（矫正过度）。比较各组的人口统计学、手术和影像学参数以及PJK发生率。
与低PT组相比，高PT组患者的基线胸椎后凸（TK）、腰椎前凸（LL）显著更低，而骨盆入射角 - 腰椎前凸（PI - LL）和T1倾斜角（T1PA）更大（所有P<0.05）。值得注意的是，高PT组的PJK发生率显著高于低PT组（43.2%对12.2%，χ² = 19.612，P<0.001）。按年龄校正的PT矫正进一步分层显示，低PT组和高PT组内各亚组的影像学参数存在显著差异。此外，在高PT组患者中，PT矫正过度组的PJK发生率（11/38，28.9%）显著低于PT矫正不足组（14/23，60.9%）和理想矫正组（10/20，50%）（χ² = 6.449，P = 0.040）。
高PT组患者代表骨盆代偿能力耗尽的患者，与低PT组相比，PJK风险显著更高。术后按年龄校正的PT矫正进一步分层显示，在高PT组中，PT矫正过度与最低的PJK发生率相关，而矫正不足风险最高。这些发现表明，基线骨盆失代偿严重的患者可能受益于更积极的PT矫正，为脊柱内固定提供稳定基础并改善ASD手术的临床结果。
