Alzakri Abdulmajeed, Vergari Claudio, Van den Abbeele M, Gille Olivier, Skalli Wafa, Obeid Ibrahim
Arts et Metiers ParisTech, LBM/Institut de Biomecanique Humaine Georges Charpak, 151 bd de l'Hopital, 75013 Paris, France; Bordeaux University Hospital, Department of Spinal Surgery, Unit 1, C.H.U Tripode Pellegrin, Place Amélie Raba Léon, 33076 Bordeaux, France; Orthopedic Department, College of Medicine, King Saud University, Riyadh, Saudi Arabia.
Arts et Metiers ParisTech, LBM/Institut de Biomecanique Humaine Georges Charpak, 151 bd de l'Hopital, 75013 Paris, France.
Spine Deform. 2019 Mar;7(2):236-244. doi: 10.1016/j.jspd.2018.06.014.
Case-control study.
To analyse global sagittal alignment including the cranial center of mass (CCOM) and proximal junctional kyphosis (PJK) in adolescent idiopathic scoliosis (AIS) patients treated with posterior instrumentation.
PJK plays an important role in the global sagittal alignment in AIS patients. Maintaining the head above the pelvis allows for a minimization of energy expense in ambulation and upright posture. Numerous studies have been performed to understand the PJK phenomena in AIS patients. However, to our knowledge, no study performed on AIS patients included the head in the analysis of global sagittal alignment and PJK.
This study included 85 AIS patients and 51 asymptomatic adolescents. Low-dose bi-planar radiographs were acquired for each subject preoperatively and at the two-year follow-up. Two global sagittal alignment parameters were calculated, that is, the angle between the vertical and the line joining the center of the bi-coxofemoral axis (HA) and either the most superior point of the dentiform apophysis of C2 (OD) or the cranial center of mass (CCOM).
Among normal adolescents, the average OD-HA and CCOM-HA angles were -2.3° ± 2° and -1.5° ± 1.8°, respectively. Among AIS patients, the average OD-HA and CCOM-HA angles were, respectively, -2.3° ± 1.9° and -1.3° ± 1.8° preoperatively and -2.8° ± 1.7° and -1.9° ± 1.7° at the last follow-up. Overall, 13% of the patients developed PJK postoperatively. Case-by-case analysis showed that adjusting the thoracic kyphosis and the compensations required to maintain this constant could provide explanatory elements.
OD-HA and CCOM-HA angles remain almost constant among the normal group and patients, pre- and postoperatively, whether PJK or non-PJK. Five patients without PJK and only one patient with PJK produced abnormal values relative to the asymptomatic subjects. Therefore, it could be concluded that PJK is a compensation mechanism, which allows for CCOM-HA and, to a lesser extent, OD-HA to remain invariant.
Level III.
病例对照研究。
分析接受后路内固定治疗的青少年特发性脊柱侧凸（AIS）患者的整体矢状面排列情况，包括颅质心（CCOM）和近端交界性后凸（PJK）。
PJK在AIS患者的整体矢状面排列中起重要作用。保持头部位于骨盆上方可使行走和直立姿势时的能量消耗最小化。已经进行了大量研究来了解AIS患者中的PJK现象。然而，据我们所知，没有针对AIS患者的研究在整体矢状面排列和PJK分析中纳入头部。
本研究纳入了85例AIS患者和51例无症状青少年。在术前和两年随访时为每个受试者拍摄低剂量双平面X线片。计算两个整体矢状面排列参数，即垂直方向与连接双侧股骨髋臼轴中心（HA）与C2齿状突最上点（OD）或颅质心（CCOM）的连线之间的夹角。
在正常青少年中，平均OD-HA和CCOM-HA角度分别为-2.3°±2°和-1.5°±1.8°。在AIS患者中，术前平均OD-HA和CCOM-HA角度分别为-2.3°±1.9°和-1.3°±1.8°，末次随访时分别为-2.8°±1.7°和-1.9°±1.7°。总体而言，13%的患者术后发生PJK。逐例分析表明，调整胸椎后凸以及维持该常数所需的代偿可提供解释因素。
无论是否发生PJK，正常组和患者术前及术后的OD-HA和CCOM-HA角度几乎保持恒定。5例未发生PJK的患者和仅1例发生PJK的患者相对于无症状受试者产生了异常值。因此，可以得出结论，PJK是一种代偿机制，可使CCOM-HA以及在较小程度上使OD-HA保持不变。
III级。
