Ex vivo estimation of thoracolumbar vertebral body compressive strength: The relative contributions of bone densitometry and vertebral morphometry
Rent the article at a discountRent now
* Final gross prices may vary according to local VAT.Get Access
The estimation of vertebral fracture risk in individuals with suspected osteopenia is commonly based on measurements of lumbar spine bone density. The efficacy of vertebral size and deformity, as assessed by vertebral morphometry, in the prediction of fractures has been less studied. In an ex vivo investigation the regional relationships between vertebral size, vertebral deformity, bone density and compressive strength throughout the thoracolumbar spine were examined. In 16 vertebral columns (T1–L5) the bone mineral content (BMC) and bone mineral density (BMD) of each segment were measured using lateral projection dual-energy X-ray absorptiometry, and the vertebral cancellous density (VCD) and mid-vertebral cross-sectional area (CSA) measured using quantitative computed tomography. Vertebral body heights were determined from mid-sagittal CT scans, and vertical height ratios calculated for each segment. The failure load and failure stress of the isolated vertebral bodies were determined using a material testing device. Separate analyses were performed for the upper (T1–4), middle (T5–8) and lower (T9–12) thoracic, and lumbar (L1–5) segments. In all regions, failure load was strongly correlated with BMD (r=0.82–0.86), moderately correlated with VCD (r=0.60–0.71) and vertebral height (r=0.22–0.49), and poorly correlated with the height ratios (r=0.04–0.33). Failure stress was best predicted by BMD (r=0.73–0.78) and VCD (r=0.70–0.78) but was poorly correlated with all morphometric variables (r=0.01–0.33). The segmental correlations between BMD and VCD ranged fromr=0.49 tor=0.79. For all regions, BMD and VCD were included in the stepwise regression models for predicting failure load and failure stress. Either the mid-vertebral height or CSA were included in all the failure load models, while mid-vertebral height was included in only one of the failure stress models. The results suggest that vertebral deformity and size (as assessed by vertebral morphometry) make only a minor contribution to the prediction of vertebral strength additional to that provided by bone densitometry alone. The consistent regional relationships between variables appear to support the practice of global fracture risk assessment based on lumbar spine densitometry.
- Overgaard K, Hansen M, Riis B, Christiansen C. Discriminatory ability of bone mass measurements (SPA and DEXA) for fractures in elderly postmenopausal women. Calcif Tissue Int 1992;50:30–5.
- Pacificini R, Rupich RC, Avioli LV. Vertebral cortical bone mass measurement by a new quantitative computer tomography method: correlations with vertebral trabecular bone measurements. Calcif Tissue Int 1990;47:215–20.
- Eriksson SAV, Isberg BO, Lingren JU. Prediction of vertebral strength by dual photon absorptiometry and quantitative computed tomography. Calcif Tissue Int 1989;44:243–50.
- Edmondston SJ, Singer KP, Day RE, Price RI, Breidahl PD. In vitro relationships between vertebral bone density, size and compressive strength in the elderly thoracolumbar spine. Clin Biomech 1994;9:180–6.
- Singer KP, Edmondston SJ, Day RE, Price RI, Breidahl PD. Prediction of thoracic and lumbar vertebral body compressive strength: correlations with bone mineral density and vertebral region. Bone 1995;17:167–74.
- Gilsanz V, Loro ML, Roe TF, Sayre J, Gilsanz R, Schulz EE. Vertebral size in elderly women with osteoporosis: mechanical implications and relationships to fractures. J Clin Invest 1995;95:2332–7.
- Ross P, Davis J, Epstein R, Wasnich R. Pre-existing fractures and bone mass predict vertebral fracture incidence in women. Ann Intern Med 1991;114:919–23.
- Ross P, Genant H, Davis J, Miller P, Wasnich R. Predicting vertebral fracture incidence from prevalent fractures and bone density among non-black, osteoporotic women. Osteoporosis Int 1993;3:120–6.
- Genant H, Gluer C-C, Lotz J. Gender differences in bone density, skeletal geometry, and fracture biomechanics. Radiology 1994;190:636–40.
- Edmondston SJ, Singer KP, Day RE, Price RI, Breidahl PD. Relationships between done mineral density, vertebral shape and thoracic curvature in the elderly thoracolumbar spine. Br J Radiol 1994;67:969–75.
- Edmondston SJ, Singer KP, Price RI, Breidahl PD. Accuracy of lateral dual-energy X-ray absorptiometry for the determination of bone mineral content in the thoracic and lumbar spine: an in vitro study. Br J Radiol 1993;66:309–13.
- De Smet AA, Robinson RG, Johnson BE, Lukert BP. Spinal compression fractures in osteoporotic women: patterns and relationship to hyperkyphosis. Radiology 1988;166:497–500.
- Gutteridge DH, Drury P, Faulkner DL, Thompson RI, Price RI, Retallack RW. Radiological diagnosis of prevalent vertebral fractures: demise of the 20% height loss criterion. In: Proceedings of the 11th International Bone Densitometry Workshop, Oregon, USA, 1995;14.
- Kleerekoper M, Nelson D. Vertebral fracture or vertebral deformity? Calcif Tissue Int 1992;50:5–6.
- Leigh JP. Assessing the importance of an independent variable in multiple regression: is stepwise unwise? J Clin Epidemiol 1988;41:669–77.
- Hayes W, Piazza S, Zysset P. Biomechanics of fracture risk prediction of the hip and spine by quantitative computed tomography. Radiol Clin North Am 1991;29:1–18.
- Diaciniti D, Acca M, D'Erasmo E, Tomei E, Mazzuoli GF. Age changes in vertebral morphometry. Calcif Tissue Int 1995;57:426–9.
- Brinckmann P, Frobin W, Hierholzer E, Horst M. Deformation of the vertebral end-plate under axial loading of the spine. Spine 1983;8:851–6.
- Kurowski P, Kubo A. The relationship of degeneration of the intervertebral disc to mechanical loading conditions on lumbar vertebrae. Spine 1986;11:726–31.
- Mizrahi J, Silva M, Keaveny T, Edwards W, Hayes W. Finite element stress analysis of the normal and osteoporotic lumbar vertebral body. Spine 1993;18:2088–96.
- Ex vivo estimation of thoracolumbar vertebral body compressive strength: The relative contributions of bone densitometry and vertebral morphometry
Volume 7, Issue 2 , pp 142-148
- Cover Date
- Print ISSN
- Online ISSN
- Additional Links
- Bone density
- Fracture risk
- Vertebral strength
- Industry Sectors
- Author Affiliations
- 1. School of Physiotherapy, Curtin University, Selby Street, Shenton Park, 6008, Western Australia, Australia
- 2. Department of Diagnostic Radiology, Royal Perth Hospital, Perth, Western Australia
- 3. Department of Bioengineering, Royal Perth Hospital, Perth, Western Australia
- 4. Department of Medical Technology and Physics, Sir Charles Gairdner Hospital, Perth, Western Australia