Kozanek Michal, Wang Shaobai, Passias Peter G, Xia Qun, Li Gang, Bono Christopher M, Wood Kirkham B, Li Guoan
Department of Orthopaedic Surgery, MA General Hospital and Harvard Medical School, Boston, 02114, USA.
Spine (Phila Pa 1976). 2009 Sep 1;34(19):E689-96. doi: 10.1097/BRS.0b013e3181ab4456.
Controlled laboratory study.
To measure the range of motion of lumbar facet (zygapophyseal) joints in vivo during various functional weight-bearing positions of the upper body.
Determination of normal in vivo motion of the lumbar facet joints remains elusive despite numerous in vitro studies, animal models, and finite element simulations. Alterations in motion of the facet joints have been thought to be associated with various types of lumbar spine pathology including disc degeneration, facet degeneration, and neural impingement.
Eleven healthy subjects underwent magnetic resonance imaging (MRI) to obtain three-dimensional models of the lumbar vertebrae from L2-L5. Each patient was then scanned using a dual-fluoroscopic imaging system while positioning the body in different postures: maximal forward-backward bend, side-to-side bending, and maximal left-right torsion. This fluoroscopic set-up was then recreated in solid modeling software where positions of the vertebrae were reproduced at each studied posture by matching the MRI-based models to the fluoroscopic images. The kinematics was measured using a Cartesian coordinate system placed in the center of each facet. The facet orientation in the sagittal and transverse plane was also determined.
During flexion-extension movements of the trunk, the facet joints rotated primarily along the mediolateral axis (average: 2 degrees -6 degrees ) and were translated in the cephalad caudad direction (average: 2-4 mm). However, during lateral bending and twisting, the facet joints did not rotate or translate in 1 dominant direction. Instead, the resulting motion represented a coupling of rotation and translation in different directions (average: <5 degrees and 3 mm). Further, the kinematic behavior of the facets of the upper lumbar spine (L2-L3 and L3-L4) were similar but different from that of the lower lumbar spine (L4-L5).
These findings provide baseline information to enable the study of kinematic changes that occur in pathologic conditions of the spine and to determine how these might be affected following surgical intervention.
对照实验室研究。
测量上半身在各种功能性负重姿势下腰椎小关节（关节突关节）的体内活动范围。
尽管有大量的体外研究、动物模型和有限元模拟，但腰椎小关节正常体内运动的确定仍然难以捉摸。小关节运动的改变被认为与各种类型的腰椎病理状况有关，包括椎间盘退变、小关节退变和神经受压。
11名健康受试者接受磁共振成像（MRI）以获取L2-L5腰椎的三维模型。然后，使用双荧光透视成像系统对每位患者进行扫描，同时将身体置于不同姿势：最大前后弯曲、左右侧弯和最大左右扭转。然后在实体建模软件中重新创建这种荧光透视设置，通过将基于MRI的模型与荧光透视图像匹配，在每个研究姿势下再现椎骨的位置。使用置于每个小关节中心的笛卡尔坐标系测量运动学。还确定了矢状面和横断面的小关节方向。
在躯干屈伸运动期间，小关节主要沿中外侧轴旋转（平均：2度-6度），并在头尾方向平移（平均：2-4毫米）。然而，在侧弯和扭转期间，小关节没有在1个主导方向上旋转或平移。相反，产生的运动代表了不同方向上旋转和平移的耦合（平均：<5度和3毫米）。此外，上腰椎（L2-L3和L3-L4）小关节的运动学行为相似，但与下腰椎（L4-L5）不同。
这些发现提供了基线信息，以便能够研究脊柱病理状况中发生的运动学变化，并确定手术干预后这些变化可能如何受到影响。
