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Importance of the intersegmental trunk
muscles for the stability of the lumbar spine. A biomechanical study in
vitro. |
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AUTHORS: |
Quint U; Wilke HJ; Shirazi-Adl A; Parnianpour
M; Loer F; Claes LE |
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AUTHOR AFFILIATION: |
Orthopaedic Clinic University of Essen,
Germany. tok030@sp2.power.uni- essen.de |
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SOURCE: |
Spine 1998 Sep 15;23(18):1937-45 |
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CITATION IDS: |
PMID: 9779525 UI: 98452561 |
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ABSTRACT: |
STUDY DESIGN: A biomechanical study was performed to determine the
consequences of a simulation of muscle forces on the loads imposed
on the functional spinal units. OBJECTIVES: No biomechanical study
has investigated the effect of incorporation of agonist and
antagonist muscle forces on the loading of functional spinal units.
SUMMARY OF BACKGROUND DATA: Spinal disorders and low back pain are
increasingly becoming a worldwide problem. Traditional conservative
therapies are intended to strengthen the muscles of the trunk using
a judicious regimen of physical exercises. METHODS: Eighteen whole,
fresh-frozen human cadaveric lumbar spine specimens (L2-S2; average
age, 53.4 years) were tested in a spine tester using pure
flexion-extension, lateral bending, and axial moments. The effects
of coactivation of psoas and multifidus muscles on L4-L5 mobility
were simulated in vitro by applying two pairs of corresponding force
vectors to L4. The segmental stability was defined by the
correlation of an applied moment to the resultant deformation as
shown in load-displacement curves, and the range of motion was
defined as the angular deformation at maximum load. RESULTS: The
coactivation of muscles was accompanied by a 20% decrease in the
range of motion (i.e., a significant increase in stability) during
lateral bending and axial moments. Application of flexion- extension
moments and muscle coactivation resulted in a 13% increase in the
sagittal range of motion. CONCLUSIONS: The action of the
intersegmental agonist and antagonist muscles biomechanically
increases the overall stiffness (stability) of the intervertebral
joints in axial torque and lateral bending, whereas it may
destabilize the segment in flexion. |
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MAIN MESH HEADINGS: |
Lumbar
Vertebrae/*physiology
Muscle, Skeletal/*physiology
*Range of Motion, Articular |
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ADDITIONAL MESH HEADINGS: |
Biomechanics
Cadaver
Human
In Vitro
Middle Age
Muscle Contraction/physiology
Statistics, Nonparametric
Support, Non-U.S. Gov't
Weight-Bearing |
