Abstract
Background context
Currently, artificial spinal discs require transection or partial removal of the annulus
fibrosis in order to excise the nucleus and implant a prosthetic nucleus or implant
a total disc device, respectively. Preservation of the annulus for prosthetic disc
replacement maintains the function of the annulus and may improve annulus load sharing
with the prosthesis.
Purpose
To quantify the biomechanical characteristics of an annular sparing intervertebral
prosthetic disc (IPD) in a lumbar calf spine model. The aim of the study was to determine
whether altering the stiffness of the elastic component of this unique prosthesis
would correspond to changes of the overall reconstructed disc.
Study design/setting
A biomechanical study was conducted in vitro using cadaveric calf spines such that
each specimen served as its own control. Investigations were performed at the Minneapolis
Medical Research Foundation, Orthopaedic Biomechanics Laboratory.
Methods
Six L45 or L56 motion segments (from which the posterior elements had been removed)
were studied in axial compression, sagittal and lateral bending and torsion. These
load states were applied to the intact, denucleated and prosthetically reconstructed
disc using four IPDs of differing stiffness.
Results
Load-displacement testing demonstrated that stiffer IPDs resulted in a decreased range
of motion and neutral zone, and greater stiffness of the reconstructed disc. Disc
reconstruction with the stiffest IPD approximated the behavior of the intact disc.
Conclusions
The overall biomechanical characteristics of a reconstructed disc are related to the
stiffness of a nucleus prosthesis. The similarities in the mechanical behavior of
reconstructed and intact discs suggest that additional feasibility studies for the
annulus-sparing IPD are warranted.
Keywords
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References
- Adjacent segment failure above lumbosacral fusions instrumented to L1 or L2.Spine J. 2002; 2: 48S
- Biomechanical behaviour of a prosthetic lumbar nucleus.Acta Neurochir. 1999; 141: 1083-1087
- A spiral implant as nucleus prosthesis in the lumbar spine.Eur Spine J. 2002; 11: S149-S153
- New technologies in spine: nucleus replacement.Spine. 2002; 27: 1245-1247
- Results of disc prosthesis after a minimum follow-up period of 2 years.Spine. 1996; 21: 995-1000
- Indications for full prosthetic disc arthroplasty: a correlation of clinical outcome against a variety of indications.Eur Spine J. 2002; 11: S131-S136
- Total disc replacement arthroplasty using the AcroFlex lumbar disc: a non-human primate model.Eur Spine J. 2002; 11: S115-S123
- Artificial disc replacement: preliminary report with a 3-year minimum follow-up.Spine. 1993; 18: 1061-1087
- Materials and design concepts for an intervertebral disc spacer:.J Appl Biomater. 1995; 6: 117-123
Buttermann GR, Beaubien BP. Load sharing of a prosthetic nucleus in response to external loads. Paper presented at: 3rd Annual Meeting of the Spine Arthroplasty Society; May 2003; Scottsdale, AZ.
- Material properties of the normal medial bovine meniscus.J Orthop Res. 1989; 7: 771-782
- Lumbar intradiscal pressure after posterolateral fusion and pedicle screw fixation.Tohoku J Exp Med. 1998; 186: 243-253
- Mechanical behavior of the human lumbar and lumbosacral spine as shown by three-dimensional load-displacement curves.J Bone Joint Surg Am. 1994; 76: 413-424
- Posterior augmentation of an anterior lumbar interbody fusion: minimally invasive fixation versus pedicle screws in vitro.Spine. 2004; (In press)
- Biomechanical comparison of calf and human spines.J Ortho Res. 1996; 14: 500-503
- Disc pressure measurements.Spine. 1981; 6: 93-97
- Loads on the lumbar spine. Validation of a biomechanical analysis by measurements of intradiscal pressures and myoelectric signals.J Bone Joint Surg. 1982; 64A: 713-720
- Biomechanical properties of human intervertebral discs subjected to axial dynamic compression. A comparison of lumbar and thoracic discs.Spine. 1984; 9: 725-733
- The structural components of the intervertebral disc. A study of their contributions to the ability of the disc to withstand compressive forces.J Bone Joint Surg. 1974; 56A: 675-687
- Effects of disc injury on mechanical behavior of the human spine.Spine. 1984; 9: 707-713
- Change of disc height, radial disc bulge, and intradiscal pressure from discectomy. An in vitro investigation on human lumbar discs.Spine. 1991; 16: 641-646
- A comparison of the effects of automated percutaneous diskectomy and conventional diskectomy on intradiscal pressure, disk geometry, and stiffness.J Spinal Disord. 1994; 7: 317-325
- The effect of various nucleotomy techniques on biomechanical properties of the intervertebral disk.Z Orthop Ihre Grenzgeb. 1999; 137 ([in German]): 206-210
- Some mechanical tests on the lumbosacral spine with particular reference to the intervertebral discs.J Bone Joint Surg. 1957; 39A: 1135-1164
- New observations on the mechanical behavior of lumbar discs.Acta Ortho Scand. 1954; 23: 254-283
- Materials and design concepts for an intervertebral disc spacer:.J Appl Biomater. 1994; 5: 125-132
- Deformation of the thoracolumbar intervertebral joints in response to external loads. A biomechanical study using autopsy material.J Bone Joint Surg. 1972; 54A: 511-533
- Dynamic compressive properties of human lumbar intervertebral joints: a comparison between fresh and thawed specimens.J Biomech. 1988; 21: 425-433
- Mechanical properties of human lumbar spine motion segments: influences of age, sex, disc level, and degeneration.Spine. 1979; 4: 1-8
- Mechanical properties of human lumbar spine motion segments:.J Biomech Eng. 1979; 101: 46-52
- Effects of fluid injection on mechanical properties of intervertebral discs.J Biomech. 1979; 12: 453-458
- Mechanical behavior of the human spine and lumbosacral spine as shown by three dimensional load-displacement curves.J Bone Joint Surg. 1994; 76A: 413-424
- Experimental measurement of ligament force, facet force, and segment motion in the human lumbar spine.J Biomech. 1993; 26: 427-438
- Requirements for an artificial intervertebral disc.Int J Artif Organs. 2001; 24: 311-321
- Mechanical properties of lumbar spinal motion segments as affected by partial disc removal.Spine. 1986; 11: 1008-1012
- Comparative biomechanical studies following automated percutaneous nucleotomy and discotomy.Z Orthop Ihre Grenzgeb. 1993; 131 ([in German]): 234-240
Article info
Publication history
Accepted:
November 10,
2003
Received:
May 28,
2003
Footnotes
☆FDA device/drug status: investigational/not approved: Prosthetic nucleus.
☆Author GRB acknowledges a financial relationship (grant research support from and board member for Dynamic Spine LLC) that may indirectly relate to the subject of this research.
Identification
Copyright
© 2004 Elsevier Inc. Published by Elsevier Inc. All rights reserved.
