Age‑related changes of the spinal cord: A biomechanical study

Okazaki,Tomoya; Kanchiku,Tsukasa; Nishida,Norihiro; Ichihara,Kazuhiko; Sakuramoto,Itsuo; Ohgi,Junji; Funaba,Masahiro; Imajo,Yasuaki; Suzuki,Hidenori; Chen,Xian; Taguchi,Toshihiko

doi:10.3892/etm.2018.5796

Age‑related changes of the spinal cord: A biomechanical study

Authors:
- Tomoya Okazaki
- Tsukasa Kanchiku
- Norihiro Nishida
- Kazuhiko Ichihara
- Itsuo Sakuramoto
- Junji Ohgi
- Masahiro Funaba
- Yasuaki Imajo
- Hidenori Suzuki
- Xian Chen
- Toshihiko Taguchi
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Affiliations: Department of Orthopedic Surgery, Yamaguchi University Graduate School of Medicine, Ube, Yamaguchi 7558505, Japan, Non Profit Organization Corporation Japan Orthopedic Biomechanics Institute, Hofu, Yamaguchi 7470814, Japan, Department of Mechanical and Electrical Engineering, Tokuyama College of Technology, Gakuendai, Shunan, Yamaguchi 7458585, Japan, Department of Mechanical Engineering, Yamaguchi University, Ube, Yamaguchi 7558611, Japan
Published online on: January 24, 2018 https://doi.org/10.3892/etm.2018.5796
Pages: 2824-2829
Copyright: © Okazaki et al. This is an open access article distributed under the terms of Creative Commons Attribution License.

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Abstract

Although it is known that aging plays an important role in the incidence and progression of cervical spondylotic myelopathy (CSM), the underlying mechanism is unclear. Studies that used fresh bovine cervical spinal cord report the gray matter of the cervical spinal cord as being more rigid and fragile than the white matter. However, there are no reports regarding the association between aging an tensile and Finite Element Method (FEM). Therefore, FEM was used based on the data pertaining to the mechanical features of older bovine cervical spinal cord to explain the pathogenesis of CSM in elderly patients. Tensile tests were conducted for white and gray matter separately in young and old bovine cervical spinal cords, and compared with their respective mechanical features. Based on the data obtained, FEM analysis was further performed, which included static and dynamic factors to describe the internal stress distribution changes of the spinal cord. These results demonstrated that the mechanical strength of young bovine spinal cords is different from that of old bovine spinal cords. The gray matter of the older spinal cord was significantly softer and more resistant to rupture compared with that of younger spinal cords (P<0.05). Among the old, although the gray matter was more fragile than the white matter, it was similar to the white matter in terms of its rigidity (P<0.05). The in vitro data were subjected to three compression patterns. The FEM analysis demonstrated that the stress level rises higher in the old spinal cords in response to similar compression, when compared with young spinal cords. These results demonstrate that in analyzing the response of the spinal cord to compression, the age of patients is an important factor to be considered, in addition to the degree of compression, compression speed and parts of the spinal cord compression factor.

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