A finite element modeling of the human lumbar unit including the spinal cord
Affiliation(s)
Laboratoire de Recherche Matériaux, Mesures et Applications, Institut National des Sciences Appliquées et de Technologie (INSAT), Université de Carthage, Tunis Cedex, Tunisia. SNC-Lavalin, Montréal, Canada. Tunisian Group of Spine and Spinal Cord Study and Research, Tunis, Tunisia.
Laboratoire de Recherche Matériaux, Mesures et Applications, Institut National des Sciences Appliquées et de Technologie (INSAT), Université de Carthage, Tunis Cedex, Tunisia. SNC-Lavalin, Montréal, Canada. Tunisian Group of Spine and Spinal Cord Study and Research, Tunis, Tunisia.
ABSTRACT
The purpose of this present work is to provide a tool to better understand mechanically related pathologies of the lumbar unit and the spinal structure by providing spinal cord deformations in different loading cases. In fact, spinal cord injury (SCI) resulting from a traumatic movement leades to a deformation of the neural and vascular structure of the spinal cord. And since the magnitude of the spinal cord stress is correlated with the pressure of the vertebral elements, stresses will be computed on all theses components. Physical properties of the vertebrae, various ligaments, the discs, and the spinal cord are described under simple loading as compression, and combined loading, flexion and lateral bending to evaluate the pressure undergone by different components of the lumbar unit. A nonlinear three-dimensional finite element method is used as a numerical tool to perform all the computations. This study provides accurate results for the localisation and the magnitude of maximum equivalent stress and shear stress on the lumbar unit and especially for the spinal cord. These results showed that stresses are more important when a compression of 500 N is combined with a flexion and a lateral bending. In particular, shear stresses are maximum for the spinal cord and the four intervertebral discs for the case of a flexion of 3.8 N.m and a lateral bending of 6.5 N.m.
The purpose of this present work is to provide a tool to better understand mechanically related pathologies of the lumbar unit and the spinal structure by providing spinal cord deformations in different loading cases. In fact, spinal cord injury (SCI) resulting from a traumatic movement leades to a deformation of the neural and vascular structure of the spinal cord. And since the magnitude of the spinal cord stress is correlated with the pressure of the vertebral elements, stresses will be computed on all theses components. Physical properties of the vertebrae, various ligaments, the discs, and the spinal cord are described under simple loading as compression, and combined loading, flexion and lateral bending to evaluate the pressure undergone by different components of the lumbar unit. A nonlinear three-dimensional finite element method is used as a numerical tool to perform all the computations. This study provides accurate results for the localisation and the magnitude of maximum equivalent stress and shear stress on the lumbar unit and especially for the spinal cord. These results showed that stresses are more important when a compression of 500 N is combined with a flexion and a lateral bending. In particular, shear stresses are maximum for the spinal cord and the four intervertebral discs for the case of a flexion of 3.8 N.m and a lateral bending of 6.5 N.m.
Cite this paper
Ben-Hatira, F. , Saidane, K. and Mrabet, A. (2012) A finite element modeling of the human lumbar unit including the spinal cord. Journal of Biomedical Science and Engineering, 5, 146-152. doi: 10.4236/jbise.2012.53019.
Ben-Hatira, F. , Saidane, K. and Mrabet, A. (2012) A finite element modeling of the human lumbar unit including the spinal cord. Journal of Biomedical Science and Engineering, 5, 146-152. doi: 10.4236/jbise.2012.53019.
References
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[1] Jacobs, W.B. and Gehlings, M.G., (2008) Ankylosing spondylitis and spinal cord injury: Origin,incidence, management, and avoidance. Neurosurgery Focus, 24, E12. doi:10.3171/FOC/2008/24/1/E12 [2] Morandi, X., Riffaud, L., Houedakor, J., Amlashi, S.F.A, Brassier, G. and Gallien, Ph., (2004) Caudal spinal cord ischemia after lumbar vertebral manipulation. Joint Bone Spine, 71, 344-337. doi:10.1016/S1297-319X(03)00154-4 [3] Breig, A., Renard, M., Stefano, S. and Renard, C. (1982) Régénération de la moelle après hémisection par relachement biomécanique et immobilisation chirurgicale. Anatomia Clinica, 4, 2-7. doi:10.1007/BF01798897 [4] Yao, J., Turteltaub, S.R. and Paul D.P., (2006) A three dimensional nonlinear analysis of the mechanical behavior of tissue engineered intervertebral discs under complex loads. Biomaterials, 27, 377-387. doi:10.1016/j.biomaterials.2005.06.036 [5] Shirazi-Adl, A. and Parnianpour,M., (2000) Load-bearing and stress analysis of the human spine under a novel wrapping compression loading. Clinical Biomechanics, 15, 718-725. doi:10.1016/S0268-0033(00)00045-0 [6] Whyne, C.M., Hu, S.S. and Lotz, J.C. (2001) Parametric finite element analysis of vertebral bodies affected by tumors. Journal of Biomechanics, 34, 1317-1324. doi:10.1016/S0021-9290(01)00086-0 [7] Tak-Man, J., Zhang, Ch.M. and Chow, D.H-K. (2003) Biomechanical responses of the intervertebral joints to static and vibrational loading: A finite element study. Clinical Biomechanics, 18, 790-799. doi:10.1016/S0268-0033(03)00142-6 [8] Dolan, P. and Adams, M.A. (2001) Recent advances in lumbar spinal mechanics and their significance for modeling. Clinical Biomechanics, 16, s8-s16. doi:10.1016/S0268-0033(00)00096-6 [9] Panjabi, M.M. (2003) Clinical spinal instability and lower back pain. Journal of Electromyography and Kinesiology, 13, 371-379. doi:10.1016/S1050-6411(03)00044-0 [10] Yoshihiko, K., Hideo, K., IKazuhiko, Ch., Yasuaki , I., Takanori, K., Shunichi, K., Daisuke, H., Kentaro, Y. and Toshihiko, T., (2008) Biomechanical study of cervical flexion myelopathy using a three-dimensional finite element method: Laboratory investigation. Journal Neurosurgery Spine, 8, 436-441. doi:10.3171/SPI/2008/8/5/436 [11] Wang, J.L., Parnianpour, M., Shirazi-Adl, A., Engin, E., Li, S. and Patwardhan, A. (1997) Development and validation of a viscoelastic finite element model of an L2/L3 motion segment. Theoretical and Applied Fracture Mechanics, 28, 81-93. doi:10.1016/S0167-8442(97)00032-3 [12] White, A. and Panjabi, M. (1990) Clinical biomecanics of the spine. 2nd Edition, Philadelphia. [13] Mazuchowski, E.L. and Thibault, L.E. (2003) Biomechanical properties of the human spinal cord and pia mater. 2003 Summer Bioengineering Conference, 25-29 June 2003, Key Biscayne. [14] Champain, N. (2004) Recherche des facteurs biomécaniques dans l’aggravation des scolioses idiopathiques. Thèse Biomécanique, ENSAM, 2004. [15] Singh, A., Lu, Y., Chen, Ch. and Cavanaugh, J.M. (2003) Mechanical properties of spinal nerve roots subjected to tension at different strain rates. Journal of Biomechanics, 39, 1669-1676. doi:10.1016/j.jbiomech.2005.04.023 [16] Harrison, D.E, Cailliet, R., Harrison, D.D, Troyanovich, S.J. and Harrison, S.O. (1999) A review of biomechanics of the central nervous system—Part I: Spinal canal deformations resulting from changes in posture. Journal of Manipulative and Physiological Therapeutics, 22. [17] Harrison, D.E., Cailliet, R., Harrison, D.D., Troyanovich, S.J. and Harrison, S.O. (1999) A review of biomechanics of the central nervous system—Part II: Spinal cord strains from postural loads. Journal of Manipulative and Physiological Therapeutics, 22.