中文摘要：

目的：探讨远端固定椎（lowest instrumented vertebra，LIV）和矢状面稳定椎（sagittal stable vertebra，SSV）位置关系对特发性脊柱侧凸患者后路矫形选择性胸弯融合术后远端交界性后凸（distal junctional kyphosis，DJK）发生率的影响。方法：回顾性分析153例行后路主胸弯选择性融合术的Leneke 1A型青少年特发性脊柱侧凸（AIS）患者的临床资料。SSV定义为骶骨后上角垂线接触的最远端下终板所在的椎体。根据术后远端固定椎（lowest instrumented vertebra，LIV）与SSV的关系分为两组：LIV位于SSV近端椎体为LIV＜SSV组，LIV位于SSV或其远端椎体为LIV≥SSV组。测量患者术前、术后和随访时的冠状面主弯Cobb角和脊柱-骨盆矢状面相关参数，比较两组患者术后DJK的发生率以及发生DJK与未发生DJK患者的影像学参数和SRS-22评分。结果：LIV＜SSV组31例，LIV≥SSV组122例，两组患者在性别、年龄、Risser征、手术时间、手术出血量、融合节段数、随访时间、术前影像学参数及SRS-22评分均无统计学差异（P〉0.05）。术后随访24-69个月，共有13例患者发生DJK，发生率为8.4%，LIV0.05），但末次随访时，发生DJK患者的胸椎后凸角、胸腰段后凸角、矢状面轴向距离、远端交界角均高于未发生DJK患者，且SRS-22疼痛评分低于未发生DJK患者，差异均有统计学意义（P＜0.05）。结论：远端固定椎-矢状面稳定椎位置关系显著影响Lenke 1A型AIS患者术后DJK的发生率，远端融合至SSV或其远端椎体可以显著降低术后DJK的发生率，更好地维持矢状面平衡。

英文摘要：

Objectives： To investigate the influence of relationship between lowest instrumented vertebra（LIV） and sagittal stable vertebra（SSV） on the occurrence of distal junctional kyphosis（DJK） after posterior selective fusion in Lenke 1A seoliosis. Methods： A consecutive cohort of 153 patients with Lenke 1A seoliosis who had undergone posterior selective thoracic fusion was reviewed. SSV was defined as the last vertebra with inferior endplate touched by the posterior sacrum vertical line. According to the relationship between SSV and LIV, the patients were divided into two groups： LIV〈SSV group and LIV≥SSV group. Parameters of main thoracic curve and sagittal spinal-pelvic alignment were measured in standing radiographs. Moreover, the incidence of DJK was also recorded and compared between these two groups. Results： The follow-up period ranged from 24 to 69 months. There were no significant differences in demographics, radiographs and scores of SRS-22 between two groups preoperatively. A total of 13 patients who presented with DJK（8.4%） was noted at final follow-up. The incidence of DJK in LIV〈SSV group was significantly higher than that in LIV≥ SSV group （25.8% vs. 4.1%, X^2=12.320, P〈0.001）. No significant differences were noted preoperatively in radiographic parameters and scores of SRS-22 between patients with and without DJK. However, at final follow-up, thoracic kyphosis, thoracolumbar kyphosis, sagittal vertical axis and distal junctional angle in DJK group were significantly larger than those in non-DJK group, with pain score of SRS-22 in DJK group significantly lower than that in non-DJK group（P〈0.05）. Conclusions： The current study reveals the significant influence of the relationship between SSV and LIV on the incidence of DJK after selective fusion in patients with Lenke 1A scoliosis. A LIV selected at SSV or more caudal level can significantly decrease the incidence of DJK after selective fusion in patients with Lenke 1A curve.