Physiological and degenerative loading of bovine intervertebral disc in a bioreactor: A finite element study of complex motions

Autor: Aapo Ristaniemi, Amra Šećerović, Vincent Dischl, Francesco Crivelli, Sarah Heub, Diane Ledroit, Gilles Weder, Sibylle Grad, Stephen J. Ferguson
Jazyk: angličtina
Rok vydání: 2023
Předmět:
Zdroj: Journal of the Mechanical Behavior of Biomedical Materials, 143
ISSN: 1751-6161
1878-0180
Popis: Intervertebral disc (IVD) degeneration and regenerative therapies are commonly studied in organ-culture experiments with uniaxial compressive loading. Recently, in our laboratory, we established a bioreactor system capable of applying loads in six degrees-of-freedom (DOF) to bovine IVDs, which replicates more closely the complex multi-axial loading of the IVD in vivo. However, the magnitudes of loading that are physiological (able to maintain cell viability) or mechanically degenerative are unknown for load cases combining several DOFs. This study aimed to establish physiological and degenerative levels of maximum principal strains and stresses in the bovine IVD tissue and to investigate how they are achieved under complex load cases related to common daily activities. The physiological and degenerative levels of maximum principal strains and stresses were determined via finite element (FE) analysis of bovine IVD subjected to experimentally established physiological and degenerative compressive loading protocols. Then, complex load cases, such as a combination of compression + flexion + torsion, were applied on the FE-model with increasing magnitudes of loading to discover when physiological and degenerative tissue strains and stresses were reached. When applying 0.1 MPa of compression and ±2–3° of flexion and ±1–2° of torsion the investigated mechanical parameters remained at physiological levels, but with ±6–8° of flexion in combination with ±2–4° of torsion, the stresses in the outer annulus fibrosus (OAF) exceeded degenerative levels. In the case of compression + flexion + torsion, the mechanical degeneration likely initiates at the OAF when loading magnitudes are high enough. The physiological and degenerative magnitudes can be used as guidelines for bioreactor experiments with bovine IVDs.
Journal of the Mechanical Behavior of Biomedical Materials, 143
ISSN:1751-6161
ISSN:1878-0180
Databáze: OpenAIRE
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