Kato Yoshihiko, Kanchiku Tsukasa, Imajo Yasuaki, Ichinara Kazuhiko, Kawano Syunichi, Hamanama Daiskue, Yaji Kentaro, Taguchi Toshihiko
Department of Orthopedic Surgery, Yamaguchi University Graduate School of Medicine, Ube, Yamaguchi, Japan.
J Spinal Cord Med. 2009;32(5):555-9. doi: 10.1080/10790268.2009.11754557.
BACKGROUND/OBJECTIVE: It is suspected that the speed of the motion of the spinal cord under static compression may be the cause of spinal cord injury (SCI). However, little is known about the relationship between the speed of the motion of the spinal cord and its stress distributions. The objective was to carry out a biomechanical study of SCI in patients with ossification of the longitudinal ligament without radiologic evidence of injury.
A 3-dimensional finite element spinal cord model was established. After the application of static compression, the model underwent anterior flexion to simulate SCI in ossification of the longitudinal ligament patients without radiologic abnormality. Flexion of the spine was assumed to occur at 1 motor segment. Flexion angle was 5 degrees, and flexion speeds were 0.5 degrees/s, 5 degrees/s, and 50 degrees/s. Stress distributions inside of the spinal cord were evaluated.
Stresses on the spinal cord increased slightly after the application of 5 degrees of flexion at a speed of 0.5 degrees/s. Stresses became much higher at a speed of 5 degrees/s and increased further at 50 degrees s.
The stress distribution of the spinal cord under static compression increased with faster flexion speed of the spinal cord. High-speed motion of the spinal cord under static compression may be one of the causes of SCI in the absence of radiologic abnormality.
背景/目的：有人怀疑脊髓在静态压迫下的运动速度可能是脊髓损伤（SCI）的原因。然而，关于脊髓运动速度与其应力分布之间的关系却知之甚少。目的是对无影像学损伤证据的后纵韧带骨化患者的脊髓损伤进行生物力学研究。
建立一个三维有限元脊髓模型。施加静态压迫后，该模型进行前屈以模拟无影像学异常的后纵韧带骨化患者的脊髓损伤。假设脊柱的前屈发生在1个运动节段。前屈角度为5度，前屈速度分别为0.5度/秒、5度/秒和50度/秒。评估脊髓内部的应力分布。
以0.5度/秒的速度施加5度前屈后脊髓上的应力略有增加。在5度/秒的速度下应力变得更高，在50度/秒时进一步增加。
静态压迫下脊髓的应力分布随着脊髓更快的前屈速度而增加。静态压迫下脊髓的高速运动可能是无影像学异常情况下脊髓损伤的原因之一。
