Paternostre F, Charles Y P, Sauleau E A, Steib J-P
Service de chirurgie du rachis, fédération de médecine translationnelle (FMTS), université de Strasbourg, hôpitaux universitaires de Strasbourg, 1, place de l'Hôpital, BP 426, 67091 Strasbourg cedex, France.
Service de chirurgie du rachis, fédération de médecine translationnelle (FMTS), université de Strasbourg, hôpitaux universitaires de Strasbourg, 1, place de l'Hôpital, BP 426, 67091 Strasbourg cedex, France.
Orthop Traumatol Surg Res. 2017 Feb;103(1):53-59. doi: 10.1016/j.otsr.2016.10.003. Epub 2016 Nov 23.
In the normal adult spine, a link between thoracolumbar and cervical sagittal alignment exists, suggesting adaptive cervical positional changes allowing horizontal gaze. In patients with thoracic hyperkyphosis, cervical adaptation to sagittal global alignment might be different from healthy individuals. However, this relationship has not clearly been reported in hyperkyphotic deformity.
The purpose of this study was to identify cervical sagittal alignment types observed on radiographs in young adults with thoracic hyperkyphosis. The relationship between cervical and thoracolumbar alignment as well as the effect of posterior instrumentation and adaptive positional changes of the mobile cervical segment were retrospectively analyzed.
Twenty-three patients (32.7 years; 5-year follow-up) were included. Full spine radiographic measurements were: T1 slope, T1-T4 kyphosis, T4-T12 kyphosis, L1-S1 lordosis, pelvic incidence, pelvic tilt, sacral slope, SVA C7, SVA C2, lordosis between C0-C2, C2-C7, C2-C4 and C4-C7. A Bayesian model and Spearman correlation were used.
Two alignment types existed: cervical lordosis (group A) and cervical kyphosis (group B). Preoperatively, T4-T12 kyphosis and L1-S1 lordosis were significantly higher in group A: 76.6° versus 59.4° and -72.8° versus -65.8° (probability of>5° difference P (β>5)>0.95). Pelvic incidence was higher in group A (49.8° versus 44.2°) and C0-C2 lordosis in group B (-29.4° versus -21.6°). A significant correlation existed between: T4-T12 kyphosis and C2-C7 lordosis, L1-S1 lordosis and pelvic incidence, C2-C7 lordosis and T1 slope, C2-C7 lordosis and T1-T4 kyphosis. Postoperatively, T4-T12 kyphosis decreased by 33.1° P (β>5)=0.9995), L1-S1 lordosis decreased by 17.7° (P (β>5)=0.961), T1-T4 kyphosis increased by 14.1° (P (β>5)=0.973). SVA C2 (translation) increased by 13.8mm. C0-C2 lordosis (head rotation) remained unchanged. Six patients changed cervical alignment. PJK occurred in 15 patients, unrelated to cervical alignment or proximal instrumentation level.
Two cervical alignment types, lordotic or kyphotic, were observed thoracic hyperkyphosis patients. This alignment was mainly triggered by the amount of thoracic kyphosis and lumbar lordosis, linked to pelvic incidence. Moreover, the inclination of the C7-T1 junctional area plays a key role in the amount of cervical lordosis. The correction of T4-T12 kyphosis induced compensatory modifications at adjacent segments: T1-T4 kyphosis increase (PJK) and L1-S1 lordosis decrease. Global spino-pelvic alignment and head position did not change in the sagittal plane. The cervical spine tented to keep in its preoperative position in most patients.
Level IV.
在正常成人脊柱中，胸腰段与颈椎矢状位排列之间存在关联，提示颈椎位置的适应性变化可实现水平注视。在胸椎后凸畸形患者中，颈椎对矢状面整体排列的适应性可能与健康个体不同。然而，这种关系在脊柱后凸畸形中尚未得到明确报道。
本研究的目的是确定在患有胸椎后凸畸形的年轻成人的X线片上观察到的颈椎矢状位排列类型。回顾性分析颈椎与胸腰段排列之间的关系以及后路内固定的效果和活动颈椎节段的适应性位置变化。
纳入23例患者（平均32.7岁；随访5年）。全脊柱X线测量参数包括：T1斜率、T1-T4后凸角、T4-T12后凸角、L1-S1前凸角、骨盆入射角、骨盆倾斜角、骶骨斜率、C7矢状面垂直轴、C2矢状面垂直轴、C0-C2前凸角、C2-C7前凸角、C2-C4前凸角和C4-C7前凸角。采用贝叶斯模型和Spearman相关性分析。
存在两种排列类型：颈椎前凸（A组）和颈椎后凸（B组）。术前，A组的T4-T12后凸角和L1-S1前凸角显著更高：分别为76.6°对与�9.4°以及-72.8°对-65.8°（差异>5°的概率P(β>5)>0.95）。A组的骨盆入射角更高（49.8°对44.2°），B组的C0-C2前凸角更小（-29.4°对-21.6°）。以下参数之间存在显著相关性：T4-T12后凸角与C2-C7前凸角、L1-S1前凸角与骨盆入射角、C2-C7前凸角与T1斜率、C2-C7前凸角与T1-T4后凸角。术后，T4-T12后凸角减小33.1°（P(β>5)=0.9995），L1-S1前凸角减小17.7°（P(β>5)=0.961），T1-T4后凸角增加14.1°（P(β>5)=0.973）。C2矢状面垂直轴（平移）增加13.8mm。C0-C2前凸角（头部旋转）保持不变。6例患者改变了颈椎排列。15例患者发生近端交界性后凸，与颈椎排列或近端内固定节段无关。
在胸椎后凸畸形患者中观察到两种颈椎排列类型，前凸或后凸。这种排列主要由胸椎后凸和腰椎前凸的程度引发，与骨盆入射角相关。此外，C7-T1交界区的倾斜度在颈椎前凸程度中起关键作用。T4-T12后凸的矫正导致相邻节段的代偿性改变：T1-T4后凸增加（近端交界性后凸）和L1-S1前凸减小。矢状面上整体脊柱-骨盆排列和头部位置未改变。大多数患者的颈椎倾向于保持术前位置。
IV级。
