Influence of different fixation methods on the fracture force of osteoporotic human lumbar vertebral bodies in the generation of vertebral compression fractures
Affiliations: [a] Department of Orthopedic Surgery, Physical Medicine and Rehabilitation, Ludwig Maximilians University of Munich, Munich, Germany | [b] Institute of Macroscopic and Clinical Anatomy, Graz, Austria | [c] Department of Orthopedic and Trauma Surgery, Medical University of Graz, Graz, Austria | [d] Center of Orthopedic and Trauma Surgery, Catholic Hospital Hagen, Hagen, Germany | [e] Department of Orthopedics, Agaplesion Ev. Bathildiskrankenhaus, Bad Pyrmont, Germany | [f] Institute of Legal Medicine, University of Rostock, Rostock, Germany
Correspondence:
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Corresponding author: Michael Kraxenberger, Department of Orthopedic Surgery, Physical Medicine and Rehabilitation, Ludwig Maximilians University of Munich, Marchioninistrasse 15, Munich, Bavaria, 81379, Germany. Tel.: +49 89 4400 0; E-mail: [email protected].
Abstract: BACKGROUND: The use of fresh-frozen (FF) specimens represents the gold standard for biomechanical investigations. Since FF specimens are often difficult to obtain, chemical-fixed specimens (formalin (FA), Thiel (TH)) are also used. OBJECTIVE: Since fixation methods can alter the mechanical properties of bone tissue, the purpose of this study was to examine their influence on the fracture force of lumbar vertebral bodies (VB). METHODS: First the VB were subdivided into three focus groups: FF, TH, and FA. After removing the soft tissue and the processus transverses of all VB, the endplates were planned with a thin layer of epoxy resin, in order to apply a constant strain to the surface and sub-surface. The VB were subjected to axial compression tests in order to determine fracture force. Lastly a standardized compression fracture was generated. RESULTS: The mean values of the fracture force of the focus groups were 4529.5 N (FF), 3211.3N (TH) and 2947.9N (FA). Consequently a significant difference between the FF and the other two groups could be demonstrated (p< 0.05). CONCLUSION: The preliminary tests showed that the fraction force of fresh-frozen VB were significantly higher than TH/FA-fixed VB. Therefore, these fixation methods could potentially have an influence on the biomechanical properties of VB. This leads to the assumption that if load-to-failure tests are performed, it is probably recommended to use fresh-frozen specimens.
Keywords: Vertebral body, spine, chemical fixation, compression, fracture force
