TY - JOUR
T1 - In-silico model development and validation of the L5-S1 spinal unit
AU - Vinyas,
AU - Bhat, Subraya Krishna
AU - Adhikari, Raviraja
AU - Bhat N, Shyamasunder
N1 - Funding Information:
The authors received no direct funding for this research. The author would like to express their heartfelt gratitude to Manipal Academy of Higher Education, Manipal for providing the required facilities to perform this study.
Publisher Copyright:
© 2023 The Author(s). This open access article is distributed under a Creative Commons Attribution (CC-BY) 4.0 license.
PY - 2023
Y1 - 2023
N2 - The L5-S1 segment of the spine is highly susceptible to injury, frequently causing low back pain. The segment has gained a lot of scientific interest, leading to many experimental works that can be found describing its biomechanical characteristics. But, there is a lack of work focusing on its computational studies, which can significantly aid its further studies. In the current study, a subject-specific single-segment finite element model of the L5-S1 unit was developed from a T2-mapped MRI scan. This study is mainly intended to probe the requirements for modelling the annulus of the disc and also attempts to understand the role of ligaments exclusive to the L5-S1 spinal unit to establish its validated finite element model. The annulus was represented by two different forms of hyperelastic material models (isotropic and anisotropic) for which the constants were determined from experimental data found in the literature. Their ability to impart the required characteristic was tested for the finite element model to mimic the experimental responses during sagittal and lateral moment loads. A comparison of results with the two material models is also discussed for other valuable parameters like contact pressure at the facets, maximum von-Mises stresses in the vertebrae, ligament strains, and midplane Tresca shear stresses of the annulus. The anisotropic Gasser-Ogden-Holzapfel (GOH) model was observed to deliver a response that consistently showed good compliance with the experimental response and hence, it is recommended for the computational studies of this segment.
AB - The L5-S1 segment of the spine is highly susceptible to injury, frequently causing low back pain. The segment has gained a lot of scientific interest, leading to many experimental works that can be found describing its biomechanical characteristics. But, there is a lack of work focusing on its computational studies, which can significantly aid its further studies. In the current study, a subject-specific single-segment finite element model of the L5-S1 unit was developed from a T2-mapped MRI scan. This study is mainly intended to probe the requirements for modelling the annulus of the disc and also attempts to understand the role of ligaments exclusive to the L5-S1 spinal unit to establish its validated finite element model. The annulus was represented by two different forms of hyperelastic material models (isotropic and anisotropic) for which the constants were determined from experimental data found in the literature. Their ability to impart the required characteristic was tested for the finite element model to mimic the experimental responses during sagittal and lateral moment loads. A comparison of results with the two material models is also discussed for other valuable parameters like contact pressure at the facets, maximum von-Mises stresses in the vertebrae, ligament strains, and midplane Tresca shear stresses of the annulus. The anisotropic Gasser-Ogden-Holzapfel (GOH) model was observed to deliver a response that consistently showed good compliance with the experimental response and hence, it is recommended for the computational studies of this segment.
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U2 - 10.1080/23311916.2023.2184446
DO - 10.1080/23311916.2023.2184446
M3 - Article
AN - SCOPUS:85149941591
SN - 2331-1916
VL - 10
JO - Cogent Engineering
JF - Cogent Engineering
IS - 1
M1 - 2184446
ER -