Mechanism of the spinal cord injury and the cervical spondylotic myelopathy: new approach based on the mechanical features of the spinal cord white and gray matter.
OBJECTIVE
The authors have previously investigated the mechanical properties of the white and gray matter in the bovine cervical spinal cord, demonstrating that the gray matter is more rigid, although more fragile, than the white matter. In the present study they conducted additional tensile tests on the bovine cervical spinal cord by changing strain levels and strain rates applied to the white and gray matter.


METHODS
Based on their testing, the authors found the following: 1) Stress within the spinal cord relaxes over time. 2) Intracord stress is related to the strain rates or levels. The finite element method was used to compute the stress distribution within the spinal cord under three compressive loading conditions. Results from the computations showed a different stress distribution in the white and gray matter, where the distribution of stress varied with strain rate, compression volume, and the position of compression.


CONCLUSIONS
These differences in mechanical properties between the white and gray matter constitute different mechanisms contributing to the development of tissue damage and clinical symptoms.
Ichihara
Kazuhiko
K
Department of Orthopedic Surgery, Yamaguchi University School of Medicine, Ube, Yamaguchi, Japan. biomechi@po.cc.yamaguchi-u.ac.jp
Taguchi
Toshihiko
T
Sakuramoto
Itsuo
I
Kawano
Shunichi
S
Kawai
Shinya
S
D000818:Animals; D001696:Biomechanical Phenomena; D002417:Cattle; D002574:Cervical Vertebrae / Q000293:injuries / Q000473:pathology; D004195:Disease Models, Animal; D005260:Female; D006801:Humans; D013117:Spinal Cord Compression / Q000209:etiology* / Q000473:pathology; D013118:Spinal Cord Diseases / Q000209:etiology / Q000503:physiopathology*; D013119:Spinal Cord Injuries / Q000150:complications*; D016474:Weight-Bearing