. 2023 May 13;155:111635.
doi: 10.1016/j.jbiomech.2023.111635.
Online ahead of print.
Affiliations
Affiliations
- 1 Department of Neurosurgery Massachusetts General Hospital, Harvard Medical School, Boston, MA, USA. Electronic address: [email protected].
- 2 Department of Neurosurgery Massachusetts General Hospital, Harvard Medical School, Boston, MA, USA.
- 3 Engineering Center for Orthopedic Research Excellence, The University of Toledo, Toledo, OH, USA.
- 4 Department of Mechanical Engineering, University of California, Santa Barbara, CA, USA.
- 5 San Francisco, CA, USA.
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Ali Kiapour et al.
J Biomech.
.
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. 2023 May 13;155:111635.
doi: 10.1016/j.jbiomech.2023.111635.
Online ahead of print.
Affiliations
- 1 Department of Neurosurgery Massachusetts General Hospital, Harvard Medical School, Boston, MA, USA. Electronic address: [email protected].
- 2 Department of Neurosurgery Massachusetts General Hospital, Harvard Medical School, Boston, MA, USA.
- 3 Engineering Center for Orthopedic Research Excellence, The University of Toledo, Toledo, OH, USA.
- 4 Department of Mechanical Engineering, University of California, Santa Barbara, CA, USA.
- 5 San Francisco, CA, USA.
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Abstract
The primary objective was to compare the subsidence resistance properties of a novel 3D-printed spinal interbody titanium implant versus a predicate polymeric annular cage. We evaluated a 3D-printed spinal interbody fusion device that employs truss-based bio-architectural features to apply the snowshoe principle of line length contact to provide efficient load distribution across the implant/endplate interface as means of resisting implant subsidence. Devices were tested mechanically using synthetic bone blocks of differing densities (osteoporotic to normal) to determine the corresponding resistance to subsidence under compressive load. Statistical analyses were performed to compare the subsidence loads and evaluate the effect of cage length on subsidence resistance. The truss implant demonstrated a marked rectilinear increase in resistance to subsidence associated with increase in the line length contact interface that corresponds with implant length irrespective of subsidence rate or bone density. In blocks simulating osteoporotic bone, comparing the shortest with the longest length truss cage (40 vs. 60 mm), the average compressive load necessary to induce subsidence of the implant increased by 46.4% (383.2 to 561.0 N) and 49.3% (567.4 to 847.2 N) for 1 and 2 mm of subsidence, respectively. In contrast, for annular cages, there was only a modest increase in compressive load when comparing the shortest with the longest length cage at a 1 mm subsidence rate. The Snowshoe truss cages demonstrated substantially more resistance to subsidence than corresponding annular cages. Clinical studies are required to support the biomechanical findings in this work.
Keywords:
3D Printing; Additive Manufacturing; Degenerative Disc Disease; Interbody fusion; Lumbar fusion; Spine biomechanics; Subsidence.
Copyright © 2023 The Author(s). Published by Elsevier Ltd.. All rights reserved.
Conflict of interest statement
Declaration of Competing Interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper.
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