成人脊柱畸形矫形术后早期躯体重心线（W-line）与近端交界区失败的相关性分析

Coorelation analysis between early postoperative center of gravity line (W-line) and proximal junctional failure after adult spinal deformity correction

中文关键词:  成人脊柱畸形  W-line  近端交界区失败  ROC曲线分析  长节段固定融合术

英文关键词:Adult spinal deformity  W-line  Proximal junctional failure  Receiver operating characteristic curve analysis  Long-fusion surgery

中文摘要:

  【摘要】 目的：探讨成人脊柱畸形（adult spinal deformity，ASD）矫形术后早期躯体重心线（W-line）与近端交界区失败（proximal junctional failure，PJF）的相关性。方法：回顾性分析2014年6月~2019年3月在我院行手术治疗的99例ASD患者的临床资料，其中男19例，女80例。均行单纯后路长节段（固定椎体≥4个）固定融合手术，术后随访至少满2年。测量并记录所有患者术前、术后3个月及末次随访时的脊柱-骨盆参数。在脊柱全长侧位X线片上，将经外耳道口垂线定义为W-line，根据W-line不同位置分为A组、B组及C组。测量术后3个月时W-line到S1后上角水平距离（WSD）及W-line到股骨头中心连线中点的水平距离（WHD），将W-line位置进行数值转化（the numeric value of W-line，N-W-line）：N-W-line=WHD/WSD。W-line位于参考点前方数值为正，反之为负。采用受试者工作特征（receiver operating characteristic，ROC）曲线分析得出N-W-line临界值。三组患者参数进行方差分析，应用Kaplan-Meier曲线分析非PJF生存时间。结果：ROC曲线分析得出术后3个月N-W-line临界值为±0.78[敏感度=75%，特异度=75.9%，曲线下面积（the area under the curve，AUC）=0.736，P=0.003]。A组32例，N-W-line>0.78；B组49例，-0.78≤N-W-line≤0.78；C组18例，N-W-line<-0.78。A组患者骨盆入射角（pelvic incidence，PI）最小（P＜0.05），术后3个月矢状面平衡距（P<0.001）、T1骨盆角（P<0.001）及骨盆腰椎匹配度（P<0.001）均显著小于其他两组患者。但随访中，A、B及C组分别有12例、3例及1例患者出现PJF，A组患者PJF发生率显著高于其他两组（12/32 vs 3/49 vs 1/18，P<0.001）。此外，A组患者非PJF生存时间显著低于其他两组患者（P=0.005，Log-rank检验）。B、C组患者W-line位置逐渐前移，脊柱-骨盆矢状位参数逐渐增大，但术后PJF发生率显著降低。结论：ASD患者矫形术后早期W-line位置可有效预测PJF发生。矫形手术后W-line偏后或过度偏前，术后随访中PJF发生率显著增加，矫形术后躯干呈轻度前屈为最佳。

英文摘要:

  【Abstract】 Objectives: To explore the correlation between the early postoperative center of gravity line of the human body, namely W-line in this study, and the proximal junctional failure(PJF) developing in adult spinal deformity(ASD). Methods: We retrospectively analyzed the data of 99 adult spinal deformity(ASD) patients(male: 19; female: 80) who received surgery operation in our single institution from June 2014 to March 2019. All of the patients underwent posterior long-segments(≥4 vertebras) fusion with instrumentation, and were followed up for a minimum of 24 months. The spinopelvic parameters before operation, at 3 months after operation and the final follow-up were measured and recorded. On the lateral full-spine X-ray radiographs, the vertical line through the external auditory canal was defined as the W-line, according to which, all the patients were divided into three groups: group A, group B, group C. The horizontal distance between W-line and S1 was defined as WSD, and the horizontal distance from W-line to the midpoint of the central line of the femoral head was defined as WHD. WSD and WHD were measured at 3 months after operation, and the position of W-line was converted into numeric value of W-line(N-W-line): N-W-line=WHD/WSD. The value of WSD/WHD was recorded as positive if W-line was in front of the reference point, and vice versa. The optimal location of W-line was deduced using receiver operating characteristic(ROC) curve analysis. A Kaplan-Meier curve and Log-rank were used to analyze the differences in PJF-free survival. Results: ROC curve analysis determined the optimal threshold of N-W-line at the 3rd month postoperatively was ±0.78 [sensitivity=75.0%, specificity=75.9%, the area under the curve (AUC)=0.736, P=0.003]. Then, three groups were defined as group A: the N-W-line>0.78, group B: -0.78≤N-W-line≤0.78, and C: N-W-line<-0.78, respectively. The pelvic incidence of patients in group A was the smallest among the three groups(P<0.05), and the sagittal vertical axis (P<0.001), T1 pelvic angle (P<0.001) and mismatch of pelvic incidence minus lumbar lordosis(P<0.001) at the 3rd month postoperatively were smaller than the other two groups significantly. Yet, of groups A, B and C, the number of patients occurring PJF was 12, 3, and 1, respectively, and the patients in group A suffered the highest incidence of PJF comparing with groups B and C （12/32 vs 3/49 vs 1/18, P<0.001）. Moreover, PJF-free survival was the lowest in the group A(P=0.005, Log-rank test). In groups C and B, the W-line position gradually moved forward, and the sagittal spinopelvic parameters increased gradually, while the incidence of PJF decreased significantly. Conclusions: The early postoperative W-line could be an effective predictor for PJF in ASD patients after deformity correction. ASD patients with W-line behind the sacrum or deviating away from the hip forwardly at the early post-operation would be vulnerable to PJF-developing. Those ASD patients with mildly inclination forwardly may have the optimal spinopelvic alignment after surgery.