OBJECTIVE: Although there are several classifications for cervical myelopathy, these do not take differences between spinal cord segments into account. Moreover, there has been no report of stress analyses for individual segments to date. METHODS: By using the finite element method, we constructed 3-dimensional spinal cord models comprised of gray matter, white matter, and pia mater of the second to eighth cervical vertebrae (C2-C8). We placed compression components (disc and yellow ligament) at the front and back of these models, and applied compression to the posterior section covering 10%, 20%, 30%, or 40% of the anteroposterior diameter of each cervical spinal cord segment. RESULTS: Our results revealed that, under compression applied to an area covering 10%, 20%, or 30% of the anteroposterior diameter of the cervical spinal cord segment, sites of increased stress varied depending on the morphology of each cervical spinal cord segment. Under 40% compression, stress was increased in the gray matter, lateral funiculus, and posterior funiculus of all spinal cord segments, and stress differences between the segments were smaller. CONCLUSION: These results indicate that, under moderate compression, sites of increased stress vary depending on the morphology of each spinal cord segment or the shape of compression components, and also that the variability of symptoms may depend on the direction of compression. However, under severe compression, the differences among the cervical spinal segments are smaller, which may facilitate diagnosis.
OBJECTIVE: Although there are several classifications for cervical myelopathy, these do not take differences between spinal cord segments into account. Moreover, there has been no report of stress analyses for individual segments to date. METHODS: By using the finite element method, we constructed 3-dimensional spinal cord models comprised of gray matter, white matter, and pia mater of the second to eighth cervical vertebrae (C2-C8). We placed compression components (disc and yellow ligament) at the front and back of these models, and applied compression to the posterior section covering 10%, 20%, 30%, or 40% of the anteroposterior diameter of each cervical spinal cord segment. RESULTS: Our results revealed that, under compression applied to an area covering 10%, 20%, or 30% of the anteroposterior diameter of the cervical spinal cord segment, sites of increased stress varied depending on the morphology of each cervical spinal cord segment. Under 40% compression, stress was increased in the gray matter, lateral funiculus, and posterior funiculus of all spinal cord segments, and stress differences between the segments were smaller. CONCLUSION: These results indicate that, under moderate compression, sites of increased stress vary depending on the morphology of each spinal cord segment or the shape of compression components, and also that the variability of symptoms may depend on the direction of compression. However, under severe compression, the differences among the cervical spinal segments are smaller, which may facilitate diagnosis.
Authors: Benjamin M Davies; Oliver Mowforth; Aref-Ali Gharooni; Lindsay Tetreault; Aria Nouri; Rana S Dhillon; Josef Bednarik; Allan R Martin; Adam Young; Hitoshi Takahashi; Timothy F Boerger; Virginia Fj Newcombe; Carl Moritz Zipser; Patrick Freund; Paul Aarne Koljonen; Ricardo Rodrigues-Pinto; Vafa Rahimi-Movaghar; Jefferson R Wilson; Shekar N Kurpad; Michael G Fehlings; Brian K Kwon; James S Harrop; James D Guest; Armin Curt; Mark R N Kotter Journal: Global Spine J Date: 2022-02