Original Article: PDF OnlyEnd-Plate Displacement During Compression of Lumbar Vertebra-Disc-Vertebra Segments and the Mechanism of FailureHolmes, A D BSc, PhD*; Hukins, D W L PhD, DSc*; Freemont, A J BSc, MD, FRCP Ed† Author Information *From the Departments of Medical Biophysics, University of Manchester, Manchester, England †From the Department of Pathological Sciences, University of Manchester, Manchester, England Spine 18(1):p 128-135, January 1993. Buy Abstract Seventeen specimens of lumbar discs, attached to the caudal and cranial halves of the adjacent vertebral bodies, were subjected to a maximum compressive load of 5.5 kN in six stages. The time between each stage was about 15 seconds. At each stage of compression, a radiograph of the specimen was recorded, and the bulging of the end-plate into the caudal vertebra was measured using a displacement transducer. After compression, the ash content of a bone sample and the water content of a sample of the nucleus of the disc were measured for each specimen. Sections through the specimens were examined by light microscopic study. Eight specimens did not fail, although end-plate displacement occurred during compression. The remaining nine specimens experienced fracture or permanent deformation of the end-plate. Specimens that failed had significantly lower rigidity of the end-plate and underlying trabecular bone; this rigidity was correlated with bone ash content. © Lippincott-Raven Publishers.