Assessing the biofidelity of in vitro biomechanical testing of the human cervical spine
- 3 May 2020
- journal article
- research article
- Published by Wiley in Journal of Orthopaedic Research
- Vol. 39 (6), 1217-1226
- https://doi.org/10.1002/jor.24702
Abstract
In vitro biomechanical studies of the osteoligamentous spine are widely used to characterize normal biomechanics, identify injury mechanisms, and assess the effects of degeneration and surgical instrumentation on spine mechanics. The objective of this study was to determine how well four standards in vitro loading paradigms replicate in vivo kinematics with regards to the instantaneous center of rotation and arthrokinematics in relation to disc deformation. In vivo data were previously collected from 20 asymptomatic participants (45.5 +/- 5.8 years) who performed full range of motion neck flexion-extension (FE) within a biplane x-ray system. Intervertebral kinematics were determined with sub-millimeter precision using a validated model-based tracking process. Ten cadaveric spines (51.8 +/- 7.3 years) were tested in FE within a robotic testing system. Each specimen was tested under four loading conditions: pure moment, axial loading, follower loading, and combined loading. The in vivo and in vitro bone motion data were directly compared. The average in vitro instant center of rotation was significantly more anterior in all four loading paradigms for all levels. In general, the anterior and posterior disc heights were larger in the in vitro models than in vivo. However, after adjusting for gender, the observed differences in disc height were not statistically significant. This data suggests that in vitro biomechanical testing alone may fail to replicate in vivo conditions, with significant implications for novel motion preservation devices such as cervical disc arthroplasty implants.Funding Information
- Cervical Spine Research Society (21st Century Development)
- NIH Clinical Center (R03AR056265)
This publication has 41 references indexed in Scilit:
- Optimization of compressive loading parameters to mimic in vivo cervical spine kinematics in vitroJournal of Biomechanics, 2019
- Fundamental biomechanics of the spine—What we have learned in the past 25 years and future directionsJournal of Biomechanics, 2016
- Influence of varying compressive loading methods on physiologic motion patterns in the cervical spineJournal of Biomechanics, 2016
- Narrative review of the in vivo mechanics of the cervical spine after anterior arthrodesis as revealed by dynamic biplane radiographyJournal of Orthopaedic Research, 2015
- Limitations of current in vitro test protocols for investigation of instrumented adjacent segment biomechanics: critical analysis of the literatureEuropean Spine Journal, 2015
- Motion Path of the Instant Center of Rotation in the Cervical Spine During In Vivo Dynamic Flexion-ExtensionSpine, 2013
- A Method to Simulate In Vivo Cervical Spine Kinematics Using In Vitro Compressive PreloadSpine, 2002
- A Follower Load Increases the Load-Carrying Capacity of the Lumbar Spine in CompressionSpine, 1999
- Critical load of the human cervical spine: an in vitro experimental studyClinical Biomechanics, 1998
- In vivo flexion/extension of the normal cervical spineJournal of Orthopaedic Research, 1991