European Spine Journal

, Volume 12, Issue 4, pp 413–420 | Cite as

Factors influencing stresses in the lumbar spine after the insertion of intervertebral cages: finite element analysis

  • Anne PolikeitEmail author
  • Stephen J. Ferguson
  • Lutz P. Nolte
  • Tracy E. Orr
Original Article


Intervertebral cages in the lumbar spine have been an advancement in spinal fusion to relieve low back pain. Even though initial stability is accepted as a requirement for fusion, there are other factors. The load transfer and its effect on the tissues adjacent to the cage may also play an essential role, which is not easily detectable with experimental tests. In this study the effects of an intervertebral cage insertion on a lumbar functional spinal unit were investigated using finite element analyses. The influences of cage material, cancellous bone density and spinal loading for the stresses in a functional spinal unit were evaluated. Three-dimensional (3D) finite element models of L2-L3 were developed for this purpose. An anterior approach for a monobloc, box-shaped cage was modelled. Models with cage were compared to the corresponding intact ones. The results showed that inserting a cage increased the maximum von Mises stress and changed the load transfer in the adjacent structures. Varying the cage material or the loading conditions had a much smaller influence than varying the cancellous bone density. The denser the cancellous bone, the more the stress was concentrated underneath the cage, while the remaining regions were unloaded. This study showed that the density of the underlying cancellous bone is a more important factor for the biomechanical behaviour of a motion segment stabilized with a cage, and its eventual clinical success, than the cage material or the applied load. Inserting an intervertebral cage markedly changed the load transfer. The altered stress distribution may trigger bone remodelling and explain damage of the underlying vertebrae.


Finite element analysis Lumbar spine Intervertebral cage Stress distribution 



The authors thank Dr. Qingmao Hu for assistance with the segmentation of the CT slices.


  1. 1.
    Agazzi S, Reverdin A, May D (1999) Posterior lumbar interbody fusion with cages: an independent review of 71 cases. J Neurosurg 91:186–192Google Scholar
  2. 2.
    Augat P, Link T, Lang TF, et al (1998) Anisotropy of the elastic modulus of trabecular bone specimens from different anatomical locations. Med Eng Phys 20:124–131Google Scholar
  3. 3.
    Bagby G (1988) Arthrodesis by the distraction-compression method using a stainless steel implant. Orthopedics 11:931–934Google Scholar
  4. 4.
    Boden S, Sumner D (1995) Biologic factors affecting spinal fusion and bone regeneration. Spine [Suppl] 20:102-112Google Scholar
  5. 5.
    Brantigan J, Steffee A, Lewis M, Quinn L, Persenaire J (2000). Lumbar interbody fusion using the Brantigan I/F cage for posterior lumbar interbody fusion and the variable pedicle screw placement system. Spine 25:1437–1446Google Scholar
  6. 6.
    Brinckmann P, Frobin W, Hierholzer E, Horst M (1983) Deformation of the vertebral end-plate under axial loading of the spine. Spine 8:851–856Google Scholar
  7. 7.
    Carter DR, Hayes WC (1976) Bone compressive strength: the influence of density and strain rate. Science 194:1174–1176Google Scholar
  8. 8.
    Dammak M, Shirazi-Adl A, Zukor D (1997) Analysis of cementless implants using interface nonlinear friction – experimental and finite element studies. J Biomech 30:121–129Google Scholar
  9. 9.
    Frei HP, Oxland TR, Rathonyi GC, Nolte LP (2001) The effect of nucleotomy on lumbar spine mechanics in compression and shear loading. Spine 26:2080–2089Google Scholar
  10. 10.
    Goel VK, Kong W, Han JS, Weinstein JN, Gilbertson LG (1993) A combined finite element and optimization investigation of lumbar spine mechanics with and without muscles. Spine 18:1531–1541Google Scholar
  11. 11.
    Goh J, Wong H-K, Thambay A, Yu C-S (2000) Influence of PLIF cage size on lumbar spine stability. Spine 25:35–40Google Scholar
  12. 12.
    Grant J, Oxland T, Dvorak M (2001) Mapping the structural properties of the lumbosacral vertebral endplates. Spine 26:889–896Google Scholar
  13. 13.
    Grosland N, Goel V, Grobler L (1999) Comparative biomechanical investigation of multiple interbody fusion cages: a finite element analysis. Proceedings of the 45th Annual Meeting of the Orthopaedic Research Society, AnaheimGoogle Scholar
  14. 14.
    Jost B, Cripton P, Lund T, et al (1998) Compressive strength of interbody cages in the lumbar spine: the effect of cage shape, posterior instrumentation and bone density. Eur Spine J 7:132–141Google Scholar
  15. 15.
    Kettler A, Wilke H-J, Dietl R, Krammer M, Lumenta C, Claes L (2000) Stabilizing effect of posterior lumbar interbody fusion cages before and after cyclic loading. J Neurosurg 92:87–92Google Scholar
  16. 16.
    Kumaresan S, Yoganandan N, Pintar FA (1998) Finite element modeling approaches of human cervical spine facet joint capsule. J Biomech 31:371–376Google Scholar
  17. 17.
    Kuslich S, Ulstrom C, Griffith S, Ahern J, Dowdle J (1998) The Bagby and Kuslich method of lumbar interbody fusion: history, techniques, and 2-year follow-up results of a United States prospective, multicenter trial. Spine 23:1267–1279Google Scholar
  18. 18.
    Kuslich S, Danielson G, Dowdle J, et al (2000) Four-year follow-up results of lumbar spine arthrodesis using the Bagby and Kuslich lumbar fusion cage. Spine 25:2656–2662Google Scholar
  19. 19.
    Lu M, Hutton WC (1996) Do bending, twisting, and diurnal fluid changes in the disc affect the propensity to prolapse? A viscoelastic finite element model. Spine 21:2570–2579Google Scholar
  20. 20.
    Lund T, Oxland T, Jost B, et al (1998) Interbody cage stabilisation in the lumbar spine. J Bone Joint Surg Br 80:351–359Google Scholar
  21. 21.
    Mann K, Bartel D, Wright T, Burstein A (1995) Coulomb frictional interfaces in modeling cemented total hip replacements: a more realistic model. J Biomech 28:1067–1078Google Scholar
  22. 22.
    Marchand F, Ahmed A (1990) Investigation of the laminate structure of lumbar disc anulus fibrosus. Spine 15:402–410Google Scholar
  23. 23.
    McAfee P (1999) Interbody fusion cages in reconstructive operations on the spine. Current concepts review. J Bone Joint Surg Am 81:859–880Google Scholar
  24. 24.
    McCutchen C (1962) The frictional properties of animal joints. Wear 5:1–17Google Scholar
  25. 25.
    Mulholland R (2000) Cages: outcome and complications. Eur Spine J 9:110-113Google Scholar
  26. 26.
    Otto J, Callaghan J, Brown T (2001) Methods to achieve a numerically stable finite element model of a multi-contact interface rotating platform total knee. Proceedings of the 47th Annual Meeting of the Orthopaedic Research Society, San FranciscoGoogle Scholar
  27. 27.
    Oxland TR, Lund T (2000) Biomechanics of stand-alone cages and cages in combination with posterior fixation: a literature review. Eur Spine J 9 [Suppl 1]:95–101Google Scholar
  28. 28.
    Oxland T, Lund T, Jost B, et al (1996) The relative importance of vertebral bone density and disc degeneration in spinal flexibility and interbody implant performance. Spine 21:2558–2569Google Scholar
  29. 29.
    Oxland T, Hoffer Z, Nydegger T, Rathonyi G, Nolte L-P (2000) A comparative biomechanical investigation of anterior lumbar interbody cages: central and bilateral approaches. J Bone Joint Surg Am 82:383–393Google Scholar
  30. 30.
    Pavlov P, Spruit M, Havinfa M, Anderson P, van Limbeek J, Jacobs W (2000) Anterior lumbar interbody fusion with threaded fusion cages and autologous bone grafts. Eur Spine J 9:224–229Google Scholar
  31. 31.
    Ray C (1997) Threaded titanium cages for lumbar interbody fusions. Spine 22:667–680Google Scholar
  32. 32.
    Roberts S, McCall I, Menage J, Haddaway M, Eisenstein S (1997) Does the thickness of the vertebral subchondral bone reflect the composition of the intervertebral disc? Eur Spine J 6:385–389Google Scholar
  33. 33.
    Sharma M, Langrana NA, Rodriguez J (1995) Role of ligaments and facets in lumbar spinal stability. Spine 20:887–900Google Scholar
  34. 34.
    Shirazi-Adl SA, Shrivastava SC, Ahmed AM (1984) Stress analysis of the lumbar disc-body unit in compression. A three-dimensional nonlinear finite element study. Spine 9:120–134Google Scholar
  35. 35.
    Shirazi-Adl A, Ahmed AM, Shrivastava SC (1986) Mechanical response of a lumbar motion segment in axial torque alone and combined with compression. Spine 11:914–927Google Scholar
  36. 36.
    Silva MJ, Keaveny TM, Hayes WC (1997) Load sharing between the shell and centrum in the lumbar vertebral body. Spine 22:140–150Google Scholar
  37. 37.
    Smit T, Odgaard A, Schneider E (1997) Structure and function of vertebral trabecular bone. Spine 22:2823–2833Google Scholar
  38. 38.
    Steffen T, Tsantrizos A, Aebi M (2000) Effect of implant design and endplate preparation on the compressive strength of interbody fusion constructs. Spine 25:1077–1084Google Scholar
  39. 39.
    Steffen T, Tsantrizos A, Fruth I, Aebi M (2000) Cages: designs and concepts. Eur Spine J 9 [Suppl 1]:89–94Google Scholar
  40. 40.
    Tsantrizos A, Andreou A, Aebi M, Steffen T (2000) Biomechanical stability of five stand-alone anterior lumbar interbody fusion constructs. Eur Spine J 9:14–22Google Scholar
  41. 41.
    Tsuji H, Hirano N, Ohshima H, Ishihara H, Terahata N, Motoe T (1993) Structural variation of the anterior and posterior anulus fibrosus in the development of human lumbar intervertebral disc. Spine 18:204–210Google Scholar
  42. 42.
    Tullberg T (1998) Failure of a carbon fiber implant: a case report. Spine 23:1804–1806Google Scholar
  43. 43.
    Weiner K, Fraser R (1998) Spine update: lumbar interbody cages. Spine 23:634–640Google Scholar

Copyright information

© Springer-Verlag  2003

Authors and Affiliations

  • Anne Polikeit
    • 1
    Email author
  • Stephen J. Ferguson
    • 1
  • Lutz P. Nolte
    • 1
  • Tracy E. Orr
    • 1
  1. 1.M. E. Müller Institute for Biomechanics, University of Bern, Murtenstrasse 35, PO Box 30, 3010 Bern, Switzerland

Personalised recommendations