Document Detail


Mechanical initiation of intervertebral disc degeneration.
MedLine Citation:
PMID:  10870137     Owner:  NLM     Status:  MEDLINE    
Abstract/OtherAbstract:
STUDY DESIGN: Mechanical testing of cadaveric lumbar motion segments. OBJECTIVES: To test the hypothesis that minor damage to a vertebral body can lead to progressive disruption of the adjacent intervertebral disc. SUMMARY OF BACKGROUND DATA: Disc degeneration involves gross structural disruption as well as cell-mediated changes in matrix composition, but there is little evidence concerning which comes first. Comparatively minor damage to a vertebral body is known to decompress the adjacent discs, and this may adversely affect both structure and cell function in the disc. METHODS: In this study, 38 cadaveric lumbar motion segments (mean age, 51 years) were subjected to complex mechanical loading to simulate typical activities in vivo while the distribution of compressive stress in the disc matrix was measured using a pressure transducer mounted in a needle 1.3 mm in diameter. "Stress profiles" were repeated after a controlled compressive overload injury had reduced motion segment height by approximately 1%. Moderate repetitive loading, appropriate for the simulation of light manual labor, then was applied to the damaged specimens for approximately 4 hours, and stress profilometry was repeated a third time. Discs then were sectioned and photographed. RESULTS: Endplate damage reduced pressure in the adjacent nucleus pulposus by 25% +/- 27% and generated peaks of compressive stress in the anulus, usually posteriorly to the nucleus. Discs 50 to 70 years of age were affected the most. Repetitive loading further decompressed the nucleus and intensified stress concentrations in the anulus, especially in simulated lordotic postures. Sagittal plane sections of 15 of the discs showed an inwardly collapsing anulus in 9 discs, extreme outward bulging of the anulus in 11 discs, and complete radial fissures in 2 discs, 1 of which allowed posterior migration of nucleus pulposus. Comparisons with the results from tissue culture experiments indicated that the observed changes in matrix compressive stress would inhibit disc cell metabolism throughout the disc, and could lead to progressive deterioration of the matrix. CONCLUSIONS: Minor damage to a vertebral body endplate leads to progressive structural changes in the adjacent intervertebral discs.
Authors:
M A Adams; B J Freeman; H P Morrison; I W Nelson; P Dolan
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Publication Detail:
Type:  Journal Article; Research Support, Non-U.S. Gov't    
Journal Detail:
Title:  Spine     Volume:  25     ISSN:  0362-2436     ISO Abbreviation:  Spine     Publication Date:  2000 Jul 
Date Detail:
Created Date:  2000-08-24     Completed Date:  2000-08-24     Revised Date:  2009-07-09    
Medline Journal Info:
Nlm Unique ID:  7610646     Medline TA:  Spine (Phila Pa 1976)     Country:  UNITED STATES    
Other Details:
Languages:  eng     Pagination:  1625-36     Citation Subset:  IM    
Affiliation:
University of Bristol, United Kingdom.
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MeSH Terms
Descriptor/Qualifier:
Adult
Aged
Aged, 80 and over
Biomechanics
Cadaver
Humans
Intervertebral Disk / pathology
Intervertebral Disk Displacement / pathology*,  physiopathology*
Lumbar Vertebrae / injuries*
Middle Aged
Pressure
Spinal Fractures / pathology*,  physiopathology*

From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine


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