Computational modeling of an adolescent’s reduced functional spine unit: a comparative study between isotropic and anisotropic hyperelastic intervertebral discs

Resumo

Computational finite element analysis has been used in investigations of the spine, contributing to the
understanding of its biomechanical behavior. Intervertebral discs (IVD) are structures that make the connection
between the vertebrae, allowing movement between it and, consequently, increasing the mobility of the spine and
been one of the most critical components of the spine. Therefore, the present paper has as main objective to propose
two analyzes of a reduced thoracic functional spine unit: in the first, the IVD is modeled as a hyperelastic rubber
like isotropic structure and, in the second, a hyperelastic anisotropic property is adopted to represent the fibers of
the annulus fibrosus. Finally, these models were compared with each other to assess the contribution of anisotropy
hyperelastic analysis to the biomechanical behavior of the spine. Through the results obtained, it is concluded that
the hyperelastic anisotropic models of the annulus fibrosus can bring more authentic results to the computational
models of the spine, considering the contribution of fibers and the large deformations to which soft tissues are
subjected. Furthermore, the reduced model can predict the spine's biomechanical behavior, being useful in spine
mechanical studies.