Fracture generation in human vertebrae under compression loading: The influence of pedicle preservation and bone mineral density on in vitro fracture behavior

Article type: Research Article

Authors: Kraxenberger, Michael^{a; *} | Schröder, Christian^a | Geith, Tobias^b | Büttner, Andreas^c | von Schulze-Pellengahr, Christoph^d | Birkenmaier, Christof^a | Müller, Peter E.^a | Jansson, Volkmar^a | Wegener, Bernd^a

Affiliations: [a] Department of Orthopedics, Physical Medicine and Rehabilitation, University Hospital, LMU Munich – Campus Grosshadern, Munich, Germany | [b] Institute for Clinical Radiology, University Hospital, LMU Munich – Campus Grosshadern, Munich, Germany | [c] Institute of Forensic Medicine, University Medical Center, Rostock, Germany | [d] Department of Orthopedic Surgery, Agaplesion ev. Bathildishospital, Bad Pyrmont, Germany

Correspondence: [*] Corresponding author: Michael Kraxenberger, Department of Orthopaedics, Physical Medicine and Rehabilitation, University Hospital, LMU Munich – Campus Grosshadern, Marchioninistrasse 15, 81377 Munich, Germany. Tel.: +49 89 4400 74862; Fax: +49 89 4400 74863; E-mail: Kraxenberger.michael@med.uni-muenchen.de.

Abstract: BACKGROUND: Fractured vertebral bodies are a common and wide spread health issue. OBJECTIVE: The purpose of this study was to develop a standardized method to experimentally generate compression fractures in vertebral bodies. The influence of the pedicles has been investigated with regards to the fracture behavior. The correlation between bone mineral density (BMD), the cause of fractures and the fracture behavior was investigated. METHODS: Twenty-one fresh frozen human lumbar spines were examined for bone mineral density (BMD) by means of quantitative computed tomography (qCT). All soft tissue was removed, vertebrae were carefully separated from each other and the exposed cranial and caudal endplates were covered with a thin layer of resin to generate a plane and homogeneous surface. A total of 80 vertebral bodies were tested until fracture. RESULTS: A good positive correlation was found between BMD, fracture compression force and stiffness of the vertebral body. No significant differences were found between the fractures generated in vertebral bodies with and without pedicles, respectively. CONCLUSIONS: Our model represents a consolidation of already existing testing devices. The comparative measurement of the BMD and the fracture behavior shows validity. In contrast to other authors, the force was applied to the whole vertebral body. Furthermore the upper and lower plates were not parallelized and therefore the natural anatomic shape was imitated. Fracture behavior was not altered by removing the pedicles.

Keywords: Spine, vertebral body, bone mineral density, pedicle, fracture force, osteoporosis

DOI: 10.3233/THC-171086

Journal: Technology and Health Care, vol. 26, no. 1, pp. 155-163, 2018