Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
2
pubmed:dateCreated
2004-1-6
pubmed:abstractText
We validate a technique for measuring neural arch load-bearing in cadaveric spines, and use it to test the hypothesis that such load-bearing rises to high levels in old and degenerated spines. Fifty-nine cadaveric lumbar motion segments, aged 19-92 yr, were subjected to compressive creep loading to reduce intervertebral disc water content and height to in vivo levels. The distribution of compressive "stress" within the disc was then measured by pulling a miniature pressure transducer, side-mounted in a 1.3mm-diameter needle, along its mid-sagittal diameter. During these measurements, the motion segment was subjected to a compressive load of 2 kN, and positioned in 2 degrees of extension to simulate erect standing. Measurements of compressive "stress" were integrated over disc area, and this force subtracted from the applied 2 kN to give the force resisted by the neural arch. An empirical calibration factor was applied to normalise results from each disc to values obtained under conditions when all of the compressive force could be assumed to pass through the disc. Disc degeneration was graded macroscopically on a scale of 1-4. Validation tests showed that calculated values of disc loading were proportional to actual applied load (r(2)>0.96) and predicted it with errors of 2-8%. Neural arch load-bearing in non-degenerated specimens was generally less than 20%, but averaged 49% for specimens aged over 70 yr. Multiple regression showed that neural arch load bearing (%)=14.4 x disc degeneration score+0.46 x age-35. These results indicate a substantial shift in vertebral load-bearing with increasing age and degeneration.
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:status
MEDLINE
pubmed:month
Feb
pubmed:issn
0021-9290
pubmed:author
pubmed:issnType
Print
pubmed:volume
37
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
197-204
pubmed:dateRevised
2011-11-17
pubmed:meshHeading
pubmed-meshheading:14706322-Adult, pubmed-meshheading:14706322-Aged, pubmed-meshheading:14706322-Aged, 80 and over, pubmed-meshheading:14706322-Aging, pubmed-meshheading:14706322-Cadaver, pubmed-meshheading:14706322-Compressive Strength, pubmed-meshheading:14706322-Elasticity, pubmed-meshheading:14706322-Female, pubmed-meshheading:14706322-Humans, pubmed-meshheading:14706322-Intervertebral Disc, pubmed-meshheading:14706322-Intervertebral Disc Displacement, pubmed-meshheading:14706322-Lumbar Vertebrae, pubmed-meshheading:14706322-Male, pubmed-meshheading:14706322-Middle Aged, pubmed-meshheading:14706322-Models, Biological, pubmed-meshheading:14706322-Reproducibility of Results, pubmed-meshheading:14706322-Sensitivity and Specificity, pubmed-meshheading:14706322-Stress, Mechanical, pubmed-meshheading:14706322-Weight-Bearing
pubmed:year
2004
pubmed:articleTitle
Neural arch load-bearing in old and degenerated spines.
pubmed:affiliation
Department of Anatomy, University of Bristol, Bristol BS2 8EJ, UK.
pubmed:publicationType
Journal Article, Comparative Study, In Vitro, Research Support, Non-U.S. Gov't, Evaluation Studies, Validation Studies