Han Kap-Soo, Kim Kyungsoo, Park Won Man, Lim Dae Seop, Kim Yoon Hyuk
Department of Mechanical Engineering, College of Engineering, Kyung Hee University, Yongin-si, Republic of Korea.
Proc Inst Mech Eng H. 2013 May;227(5):543-50. doi: 10.1177/0954411912474742. Epub 2013 Jan 25.
The placement of artificial disks can alter the center of rotation and kinematic pattern; therefore, forces in the spine during the motion will be affected as a result. The relationship between the location of joint center of artificial disks and forces in the spinal components is not investigated. A musculoskeletal model of the spine was developed, and three location cases of center of rotation were investigated varying 5 mm anteriorly and posteriorly from the default center. Resultant joint forces, ligament forces, facet forces, and muscle forces for each case were predicted during sagittal motion. No considerable difference was observed for joint force (maximum 14%). Anterior shift of center of rotation induced the most ligament forces (200 N) and facet forces (130 N) among the three cases. Posterior and anterior shifts of centers of rotation from the default location caused considerable changes in muscle forces, respectively: 108% and 70% of increase in multifidi muscle and 157% and 187% of increase in short segmental muscle. This study showed that the centers of rotation due to the design and the surgical placement of artificial disk can affect the kinetic results in the spine.
人工椎间盘的放置会改变旋转中心和运动模式；因此，运动过程中脊柱内的力也会受到影响。人工椎间盘关节中心位置与脊柱各部件受力之间的关系尚未得到研究。建立了一个脊柱肌肉骨骼模型，并研究了旋转中心的三种位置情况，即相对于默认中心在前后方向上各偏移5毫米。在矢状面运动过程中预测了每种情况下的合成关节力、韧带力、小关节力和肌肉力。关节力方面未观察到显著差异（最大为14%）。在三种情况中，旋转中心向前移位产生的韧带力（200牛）和小关节力（130牛）最大。旋转中心相对于默认位置向后和向前移位分别导致肌肉力发生显著变化：多裂肌增加108%和70%，短节段肌增加157%和187%。本研究表明，由于人工椎间盘的设计和手术放置导致的旋转中心会影响脊柱的动力学结果。
