Abstract
Introduction: A feature of osteoporosis is vertebral compression fractures (VCF). Experiments looking at predicting compressive strength of human lumbar vertebrae have showed a correlation between compressive strength, bone density and size of vertebral endplates. The objective of this study was to compare the actual versus predicted failure strength of osteoporotic human vertebrae in relation to creating a validated experimental model for a vertebral compression fracture.
Methods: Twenty-six human vertebrae underwent CT scanning to evaluate bone mineral density (BMD) from a large and small region of interest (ROI) within the vertebral body (VB). Cranial, caudal and verage endplate surface area (SA) measurements were recorded. Specimens were axially compressed to failure and a regression analysis undertaken in which the failure load was fitted using both BMD alone and the product of the BMD and endplate SA.
Results: Measurements of BMD from a large or small ROI showed a poor correlation when compared to vertebral failure strength. The product of BMD and endplate SA showed significant correlations with failure strength. The regression explains a significant proportion of the variation of the response variable.
Discussion: Results from this study are consistent with published data which have established a good correlation between the product of endplate SA and BMD to vertebral compressive strength. BMD values from a large ROI and average or caudal endplate area provide the best prediction of failure strength. Experience from this study suggests that the experimental model is reproducible and accurate, however, further work is required on a larger data set to verify initial findings.
Correspondence should be addressed to: Mr John O’ Dowd, SBPR, c/o BOA, The Royal College of Surgeons, 35–43 Lincoln’s Inn Fields, London WC2A 3PE.
