Abstract
Background
Disc prolapses can result from various complex load situations and degenerative changes
in the intervertebral disc. The aim of this finite element study was to find load
combinations that would lead to the highest internal stresses in a healthy and in
degenerated discs.
Methods
A three-dimensional finite element model of a lumbar spinal segment L4–L5 in different
grades of disc degeneration (healthy, mild, moderate, and severe) were generated,
in which the disc height reduction, the formation of osteophytes and the increasing
of nucleus’ compressibility were considered. The intradiscal pressure in the nucleus,
the fiber strains, and the shear strains between the annulus and the adjacent endplates
under pure and complex loads were investigated.
Results
In all grades of disc degeneration the intradiscal pressure was found to be highest
in flexion. The shear and fiber strains predicted a strong increase under lateral
bending + flexion for the healthy disc and under axial rotation and lateral bending + axial rotation for all degenerated discs, mostly located in the postero-lateral annulus.
Compared to the healthy disc, the mildly degenerated disc indicated an increase of
the intradiscal pressure and of the fiber strains, both of 25% in axial rotation.
The shear strains showed an increase of 27% in axial rotation + flexion. As from the moderately degenerated disc all measurement parameters strongly
decreased.
Interpretation
The results support how specifically changes associated with disc degeneration might
contribute to risk of prolapse. Thus, the highest risk of prolapses can be found for
healthy and mildly degenerated discs.
Keywords
To read this article in full you will need to make a payment
Purchase one-time access:
Academic & Personal: 24 hour online accessCorporate R&D Professionals: 24 hour online accessOne-time access price info
- For academic or personal research use, select 'Academic and Personal'
- For corporate R&D use, select 'Corporate R&D Professionals'
Subscribe:
Subscribe to Clinical BiomechanicsAlready a print subscriber? Claim online access
Already an online subscriber? Sign in
Register: Create an account
Institutional Access: Sign in to ScienceDirect
References
- The Biomechanics of Back Pain.Churchill, Livingston2002
- Mechanical initiation of intervertebral disc degeneration.Spine. 2000; 25: 1625-1636
- The mechanics of prolapsed intervertebral disc.Int. Orthopaed. 1982; 6: 249-253
- Prolapsed intervertebral disc A. hyperflexion injury 1981 volvo award in basic science.Spine. 1982; 7: 184-191
- Gradual disc prolapse.Spine. 1985; 10: 524-531
- Structure and mechanical properties of rat tail tendon.Biorheology. 1980; 17: 83-94
- Measurement of cadaver lumbar spine motion segment stiffness.Spine. 2002; 27: 918-922
- Computed tomography and differential diagnosis of the extruded lumbar disc.J. Comput. Assist. Tomogr. 1983; 7: 969-975
- Tensile properties of nondegenerate human lumbar anulus fibrosus.Spine. 1996; 21: 452-461
- Are there typical localisations of lumbar disc herniations? A prospective study.Acta Neurochir (Wien). 1992; 117: 143-148
- Peak stresses observed in the posterior lateral anulus.Spine. 2001; 26: 1753-1759
- Radial tensile properties of the lumbar annulus fibrosus are site and degeneration dependent.J. Orthopaed. Res. 1997; 15: 814-819
- Lett. Spine. 2002; 27: 1378
- Mechanism of disc rupture. A preliminary report.Spine. 1991; 16: 450-456
- A cadaveric study comparing discography, magnetic resonance imaging, histology, and mechanical behavior of the human lumbar disc.Spine. 1992; 17: 417-426
- Age-dependent influence of strain rate on the tensile failure of rat-tail tendon.J. Biomech. Eng. 1983; 105: 296-299
- Vertebral end-plate lesions (Schmorl’s nodes) in the dorsolumbar spine.Ann. Rheum Dis. 1976; 35: 127-132
- Single lamellar mechanics of the human lumbar anulus fibrosus.Biomech. Model Mechanobiol. 2005; 3: 125-140
- Effect of disc degeneration at one level on the adjacent level in axial mode.Spine. 1991; 16: 331-335
- Do bending, twisting, and diurnal fluid changes in the disc affect the propensity to prolapse? A viscoelastic finite element model.Spine. 1996; 21: 2570-2579
MARC. Theory and user’s manual. MacNeal-Schwender Corporation, 2001. vol Version 2001.
- Facet orientation in the thoracolumbar spine: three-dimensional anatomic and biomechanical analysis.Spine. 2004; 29: 1755-1763
- Internal intervertebral disc mechanics as revealed by stress profilometry.Spine. 1992; 17: 66-73
- Can intervertebral disc prolapse be predicted by disc mechanics?.Spine. 1993; 18: 1525-1530
- Disc degeneration affects the multidirectional flexibility of the lumbar spine.Spine. 1994; 19: 1371-1380
- Annular tears and intervertebral disc degeneration: An experimental study using an animal model.Spine. 1990; 15: 762-767
- Annular tears and disc degeneration in the lumbar spine. A post-mortem study of 135 discs.J. Bone Joint Surg. – Br. Vol. 1992; 74: 678-682
- Articular facets of the human spine. Quantitative three-dimensional anatomy.Spine. 1993; 18: 1298-1310
- A follower load increases the load-carrying capacity of the lumbar spine in compression.Spine. 1999; 24: 1003-1009
Pingel, T.H., 1991. Beitrag zur Herleitung und numerischen Realisierung eines mathematischen Modells der menschlichen Wirbelsäule. Mitteilungen aus dem Institut für Mechanik.
- Simulated influence of osteoporosis and disc degeneration on the load transfer in a lumbar functional spinal unit.J. Biomech. 2004; 37: 1061-1069
- Analysis of the influence of disc degeneration on the mechanical behaviour of a lumbar motion segment using the finite element method.J. Biomech. 2006; 39: 2484-2490
- Application of a calibration method provides more realistic results for a finite element model of a lumbar spinal segment.Clin. Biomech. 2007;
- Application of a new calibration method for a three-dimensional finite element model of a human lumbar annulus fibrosus.Clin. Biomech. 2006; 21: 337-344
- Intradiscal pressure, shear strain, and fiber strain in the intervertebral disc under combined loading.Spine. 2007; 32: 748-755
- Role of ligaments and facets in lumbar spinal stability.Spine. 1995; 20: 887-900
- Strain in fibers of a lumbar disc. Analysis of the role of lifting in producing disc prolapse.Spine. 1989; 14: 96-103
- Finite-element evaluation of contact loads on facets of an L2–L3 lumbar segment in complex loads.Spine. 1991; 16: 533-541
- Finite-element simulation of changes in the fluid content of human lumbar discs. Mechanical and clinical implications.Spine. 1992; 17: 206-212
- Mechanical response of a lumbar motion segment in axial torque alone and combined with compression.Spine. 1986; 11: 914-927
- The Mechanical Significance of the Trabecular Bone Architecture in a Human Vertebra.Technische Universität Hamburg-Harburg, Hamburg-Harburg1996 (pp. 49–53)
- The lumbar disc herniation. A computer-aided analysis of 2504 operations.Acta Orthop. Scand. 1972; 142: 1-95
- Lumbar intradiscal pressure measured in the anterior and posterolateral annular regions during asymmetrical loading.Clin. Biomech. 1998; 13: 495-505
- Deckplattenkonturen lumbaler Wirbelkörper in Abhängigkeit ihres Degenerationsstadiums.Jahrestagung der DGfB, Hamburg, Germany, Hamburg, Germany2005
- Validity and interobserver agreement of a new radiographic grading system for intervertebral disc degeneration: Part I. Lumbar spine.Eur. Spine J. 2006; 15: 720-730
- Accuracy and repeatability of a new method for measuring facet loads in the lumbar spine.J. Biomech. 2006; 39: 348-353
Article info
Publication history
Published online: September 06, 2007
Accepted:
July 11,
2007
Received:
April 12,
2007
Identification
Copyright
© 2007 Elsevier Ltd. Published by Elsevier Inc. All rights reserved.
