Abstract
Background
Epidemiological studies have found associations between lifting, lifting and twisting
and twisting alone with increased incidence of disc herniation. This study investigated
the role of repeated dynamic axial torque/twist combined with repeated flexion on
the disc herniation mechanism.
Methods
Porcine cervical spines were tested in one of the following four testing protocols:
flexion–extension only; axial torque/twist only; flexion–extension followed by axial
torque/twist; or axial torque/twist followed by flexion–extension. Plane film radiographs
and computed tomography with contrast in the nucleus were obtained at regular intervals
during and following the mechanical testing process together with final dissection
to determine the disc injury patterns.
Findings
Axial torque/twist in combination with repetitive flexion extension motion, regardless
of order, encouraged radial delamination within the annulus (67.5% of specimens).
Alternatively, repetitive flexion motion alone encouraged posterior or posterolateral
nucleus tracking through the annulus. Axial torque/twist alone was unable to initiate
a disc herniation. Both X-ray images with contrast and computed tomography were not
good at detecting radial delamination observed during dissection.
Interpretation
The clinical relevance is that twisting may cause more radial delamination while repeated
flexion causes more posterior tracking of the nucleus giving guidance for both prevention
and rehabilitation decisions. In addition, X-ray images with contrast are not effective
at detecting the radial delamination which was exacerbated by combined loading in
flexion extension and axial torque/twist.
Keywords
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References
- The relevance of torsion to the mechanical derangement of the lumbar spine.Spine. 1981; 63: 241-248
- Discs degenerate before facets.Spine. 1990; 15: 111-113
- Intervertebral disc herniation: studies on a porcine model exposed to highly repetitive flexion/extension motion with compressive force.Clin. Biomech. 2001; 16: 28-37
- The effects of torsion on the lumbar intervertebral joints: the role of torsion in the production of disc degeneration.J. Bone Joint Surg. Am. 1970; 523: 468-497
- Tensile properties of the human lumbar annulus fibrosus.Acta Orthop. Scand. 1967; : 5-91
- Aetiology, diagnosis and treatment of low back pain.Eur. Spine J. 1994; 31: 22-27
- Mechanism of disc rupture: a preliminary report.Spine. 1991; 6: 450-456
- Flexibility of lumbar spinal motion segments correlated to type of tears in the annulus fibrosus.J. Neurosurg. 2000; 91: 81-86
- An epidemiological study of lifting and twisting on the job and risk for acute prolapsed lumbar intervertebral disc.J. Bone Joint Surg. Am. 1984; 2: 61-66
- An epidemiological study of non-occupational lifting as a risk factor for herniated lumbar intervertebral disc.Spine. 1993; 18: 595-602
- An anatomical basis for spinal instability: a porcine trauma model.J. Orthop. Res. 1991; 9: 452-462
Tampier, C., 2006. Progressive Disc Herniation: An Investigation of the Mechanism Using Histochemical and Microscopic Techniques. Masters Thesis, University of Waterloo, Waterloo.
- Progressive disc herniation: an investigation of the mechanism using radiologic, histochemical and microscopic dissection techniques.Spine. 2007; 32: 2869-2874
- The porcine cervical spine as a model of the human lumbar spine: an anatomical, geometric, and functional comparison.J. Spinal Disord. 1999; 12: 415-423
Article info
Publication history
Published online: October 08, 2009
Accepted:
September 9,
2009
Received:
April 27,
2009
Identification
Copyright
© 2009 Elsevier Ltd. Published by Elsevier Inc. All rights reserved.
