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Quarrington RD, Thompson-Bagshaw DW, Jones CF. The Effect of Axial Compression and Distraction on Cervical Facet Cartilage Apposition During Shear and Bending Motions. Ann Biomed Eng 2022; 50:540-548. [PMID: 35254561 PMCID: PMC9001226 DOI: 10.1007/s10439-022-02940-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2021] [Accepted: 02/22/2022] [Indexed: 11/28/2022]
Abstract
During cervical spine trauma, complex intervertebral motions can cause a reduction in facet joint cartilage apposition area (CAA), leading to cervical facet dislocation (CFD). Intervertebral compression and distraction likely alter the magnitude and location of CAA, and may influence the risk of facet fracture. The aim of this study was to investigate facet joint CAA resulting from intervertebral distraction (2.5 mm) or compression (50, 300 N) superimposed on shear and bending motions. Intervertebral and facet joint kinematics were applied to multi rigid-body kinematic models of twelve C6/C7 motion segments (70 ± 13 year, nine male) with specimen-specific cartilage profiles. CAA was qualitatively and quantitatively compared between distraction and compression conditions for each motion; linear mixed-effects models (α = 0.05) were applied. Distraction significantly decreased CAA throughout all motions, compared to the compressed conditions (p < 0.001), and shifted the apposition region towards the facet tip. These observations were consistent bilaterally for both asymmetric and symmetric motions. The results indicate that axial neck loads, which are altered by muscle activation and head loading, influences facet apposition. Investigating CAA in longer cervical spine segments subjected to quasistatic or dynamic loading may provide insight into dislocation and fracture mechanisms.
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Affiliation(s)
- Ryan D. Quarrington
- Adelaide Spinal Research Group, Centre for Orthopaedic & Trauma Research, Adelaide Medical School, The University of Adelaide, Level 7, Adelaide Health and Medical Sciences Building, North Terrace, Adelaide, SA 5000 Australia
| | - Darcy W. Thompson-Bagshaw
- Adelaide Spinal Research Group, Centre for Orthopaedic & Trauma Research, Adelaide Medical School, The University of Adelaide, Level 7, Adelaide Health and Medical Sciences Building, North Terrace, Adelaide, SA 5000 Australia
- School of Mechanical Engineering, The University of Adelaide, Level 7, Adelaide Health and Medical Sciences Building, North Terrace, Adelaide, SA 5000 Australia
| | - Claire F. Jones
- Adelaide Spinal Research Group, Centre for Orthopaedic & Trauma Research, Adelaide Medical School, The University of Adelaide, Level 7, Adelaide Health and Medical Sciences Building, North Terrace, Adelaide, SA 5000 Australia
- School of Mechanical Engineering, The University of Adelaide, Level 7, Adelaide Health and Medical Sciences Building, North Terrace, Adelaide, SA 5000 Australia
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2
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Yamamoto S, Whyte T, Van Toen C, Melnyk A, Shewchuk J, Street J, Cripton P, Oxland TR. The diagnostic precision of computed tomography for traumatic cervical spine injury: An in vitro biomechanical investigation. Clin Biomech (Bristol, Avon) 2022; 92:105529. [PMID: 35032901 DOI: 10.1016/j.clinbiomech.2021.105529] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/09/2021] [Revised: 11/05/2021] [Accepted: 11/09/2021] [Indexed: 02/07/2023]
Abstract
BACKGROUND CT is considered the best method for vertebral fracture detection clinically, but its efficacy in laboratory studies is unknown. Therefore, our objective was to determine the sensitivity, precision, and specificity of high-resolution CT imaging compared to detailed anatomic dissection in an axial compression and lateral bending cervical spine biomechanical injury model. METHODS 35 three-vertebra human cadaver cervical spine specimens were impacted in dynamic axial compression (0.5 m/s) at one of three lateral eccentricities (low 5% of the spine transverse diameter, middle 50%, high 150%) and two end conditions (19 constrained lateral translation and 16 unconstrained). All specimens were imaged using high resolution CT imaging (246 μm). Two clinicians (spine surgeon and neuroradiologist) diagnosed the vertebral fractures based on 34 discrete anatomical structures using both the CT images and anatomical dissection. FINDINGS The sensitivity of CT was highest for fractures of the facet joint (59%) and vertebral endplate (57%), and was lowest for pedicle (13%) and lateral mass fractures (23%). The precision of CT was highest for spinous process fractures (83%) and lowest for pedicle (21%), uncinate process and lateral mass (both 23%) fractures. The specificity of CT exceeded 90% for all fractures. The Kappa value between the two reviewers was 0.52, indicating moderate agreement. INTERPRETATION In this in vitro cervical spine injury model, high resolution CT scanning missed many fractures, notably those of the lateral mass and pedicle. This finding is potentially important clinically, as the integrity of these structures is important to clinical stability and surgical fixation planning.
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Affiliation(s)
- Shun Yamamoto
- Orthopaedic and Injury Biomechanics Group, Departments of Mechanical Engineering and Orthopaedics and the School of Biomedical Engineering, University of British Columbia, Vancouver Campus, 2054-6250 Applied Science Lane, Vancouver, BC V6T 1Z4, Canada; International Collaboration on Repair Discoveries (ICORD), University of British Columbia, 818 West 10th Avenue, Vancouver, BC V5Z 1M9, Canada; Department of Orthopaedic Surgery, Jikei University Graduate School of Medicine, 3-25-8, Nishi-Shimbashi, Minato-ku, Tokyo 105-8461, Japan
| | - Tom Whyte
- Orthopaedic and Injury Biomechanics Group, Departments of Mechanical Engineering and Orthopaedics and the School of Biomedical Engineering, University of British Columbia, Vancouver Campus, 2054-6250 Applied Science Lane, Vancouver, BC V6T 1Z4, Canada; International Collaboration on Repair Discoveries (ICORD), University of British Columbia, 818 West 10th Avenue, Vancouver, BC V5Z 1M9, Canada
| | - Carolyn Van Toen
- Orthopaedic and Injury Biomechanics Group, Departments of Mechanical Engineering and Orthopaedics and the School of Biomedical Engineering, University of British Columbia, Vancouver Campus, 2054-6250 Applied Science Lane, Vancouver, BC V6T 1Z4, Canada; International Collaboration on Repair Discoveries (ICORD), University of British Columbia, 818 West 10th Avenue, Vancouver, BC V5Z 1M9, Canada
| | - Angela Melnyk
- Orthopaedic and Injury Biomechanics Group, Departments of Mechanical Engineering and Orthopaedics and the School of Biomedical Engineering, University of British Columbia, Vancouver Campus, 2054-6250 Applied Science Lane, Vancouver, BC V6T 1Z4, Canada; International Collaboration on Repair Discoveries (ICORD), University of British Columbia, 818 West 10th Avenue, Vancouver, BC V5Z 1M9, Canada
| | - Jason Shewchuk
- Department of Radiology, University of British Columbia, Vancouver General Hospital, 899 W. 12(th) Ave., Vancouver, BC V5Z 1M9, Canada
| | - John Street
- Orthopaedic and Injury Biomechanics Group, Departments of Mechanical Engineering and Orthopaedics and the School of Biomedical Engineering, University of British Columbia, Vancouver Campus, 2054-6250 Applied Science Lane, Vancouver, BC V6T 1Z4, Canada; International Collaboration on Repair Discoveries (ICORD), University of British Columbia, 818 West 10th Avenue, Vancouver, BC V5Z 1M9, Canada
| | - Peter Cripton
- Orthopaedic and Injury Biomechanics Group, Departments of Mechanical Engineering and Orthopaedics and the School of Biomedical Engineering, University of British Columbia, Vancouver Campus, 2054-6250 Applied Science Lane, Vancouver, BC V6T 1Z4, Canada; International Collaboration on Repair Discoveries (ICORD), University of British Columbia, 818 West 10th Avenue, Vancouver, BC V5Z 1M9, Canada
| | - Thomas R Oxland
- Orthopaedic and Injury Biomechanics Group, Departments of Mechanical Engineering and Orthopaedics and the School of Biomedical Engineering, University of British Columbia, Vancouver Campus, 2054-6250 Applied Science Lane, Vancouver, BC V6T 1Z4, Canada; International Collaboration on Repair Discoveries (ICORD), University of British Columbia, 818 West 10th Avenue, Vancouver, BC V5Z 1M9, Canada.
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Melnyk A, Whyte T, Van Toen C, Yamamoto S, Street J, Oxland TR, Cripton PA. The effect of end condition on spine segment biomechanics in compression with lateral eccentricity. J Biomech 2021; 128:110617. [PMID: 34628202 DOI: 10.1016/j.jbiomech.2021.110617] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/12/2020] [Revised: 06/02/2021] [Accepted: 07/05/2021] [Indexed: 11/29/2022]
Abstract
During axial impact compression of the cervical spine, injury outcome is highly dependent on initial posture of the spine and the orientation, frictional properties and stiffness of the impact surface. These properties influence the "end condition" the spine experiences in real-world impacts. The effect of end condition on compression and sagittal plane bending in laboratory experiments is well-documented. The spine is able to escape injury in an unconstrained flexion-inducing end condition (e.g. against an angled, low friction surface), but when the end condition is constrained (e.g. head pocketing into a deformable surface) the following torso can compress the aligned spine causing injury. The aim of this study was to determine whether this effect exists under combined axial compression and lateral bending. Over two experimental studies, twenty-four human three vertebra functional spinal units were subjected to controlled dynamic axial compression at two levels of laterally eccentric force and in two end conditions. One end condition allowed the superior spine to laterally rotate and translate (T-Free) and the other end condition allowed only lateral rotation (T-Fixed). Spine kinetics, kinematics, injuries and occlusion of the spinal canal were measured during impact and pre- and post-impact flexibility. In contrast to typical spine responses in flexion-compression loading, the cervical spine specimens in this study did not escape injury in lateral bending when allowed to translate laterally. The specimen group that allowed lateral translation during compression had more injuries at high laterally eccentric force, saw greater peak canal occlusions and post-impact flexibility than constrained specimens.
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Affiliation(s)
- Angela Melnyk
- Department of Orthopaedics, University of British Columbia, 2775 Laurel Street, Vancouver, BC V5Z 1M9, Canada; Department of Mechanical Engineering, University of British Columbia, 6250 Applied Science Ln #2054, Vancouver, BC V6T 1Z4, Canada; International Collaboration on Repair Discoveries (ICORD), 818 W 10(th) Ave, Vancouver, BC V5Z 1M9, Canada
| | - Tom Whyte
- Department of Mechanical Engineering, University of British Columbia, 6250 Applied Science Ln #2054, Vancouver, BC V6T 1Z4, Canada; International Collaboration on Repair Discoveries (ICORD), 818 W 10(th) Ave, Vancouver, BC V5Z 1M9, Canada.
| | - Carolyn Van Toen
- Department of Orthopaedics, University of British Columbia, 2775 Laurel Street, Vancouver, BC V5Z 1M9, Canada; Department of Mechanical Engineering, University of British Columbia, 6250 Applied Science Ln #2054, Vancouver, BC V6T 1Z4, Canada; International Collaboration on Repair Discoveries (ICORD), 818 W 10(th) Ave, Vancouver, BC V5Z 1M9, Canada
| | - Shun Yamamoto
- Department of Orthopaedics, University of British Columbia, 2775 Laurel Street, Vancouver, BC V5Z 1M9, Canada; International Collaboration on Repair Discoveries (ICORD), 818 W 10(th) Ave, Vancouver, BC V5Z 1M9, Canada
| | - John Street
- Department of Orthopaedics, University of British Columbia, 2775 Laurel Street, Vancouver, BC V5Z 1M9, Canada; International Collaboration on Repair Discoveries (ICORD), 818 W 10(th) Ave, Vancouver, BC V5Z 1M9, Canada
| | - Thomas R Oxland
- Department of Orthopaedics, University of British Columbia, 2775 Laurel Street, Vancouver, BC V5Z 1M9, Canada; Department of Mechanical Engineering, University of British Columbia, 6250 Applied Science Ln #2054, Vancouver, BC V6T 1Z4, Canada; International Collaboration on Repair Discoveries (ICORD), 818 W 10(th) Ave, Vancouver, BC V5Z 1M9, Canada
| | - Peter A Cripton
- Department of Orthopaedics, University of British Columbia, 2775 Laurel Street, Vancouver, BC V5Z 1M9, Canada; Department of Mechanical Engineering, University of British Columbia, 6250 Applied Science Ln #2054, Vancouver, BC V6T 1Z4, Canada; School of Biomedical Engineering, University of British Columbia, 2222 Health Sciences Mall, Biomedical Research Centre (BRC), Vancouver, BC V6T 1Z3, Canada; International Collaboration on Repair Discoveries (ICORD), 818 W 10(th) Ave, Vancouver, BC V5Z 1M9, Canada
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Whyte T, Barker JB, Cronin DS, Dumas GA, Nolte LP, Cripton PA. Load-Sharing and Kinematics of the Human Cervical Spine Under Multi-Axial Transverse Shear Loading: Combined Experimental and Computational Investigation. J Biomech Eng 2021; 143:1097188. [PMID: 33537737 DOI: 10.1115/1.4050030] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/27/2020] [Indexed: 11/08/2022]
Abstract
The cervical spine experiences shear forces during everyday activities and injurious events yet there is a paucity of biomechanical data characterizing the cervical spine under shear loading. This study aimed to (1) characterize load transmission paths and kinematics of the subaxial cervical spine under shear loading, and (2) assess a contemporary finite element cervical spine model using this data. Subaxial functional spinal units (FSUs) were subjected to anterior, posterior, and lateral shear forces (200 N) applied with and without superimposed axial compression preload (200 N) while monitoring spine kinematics. Load transmission paths were identified using strain gauges on the anterior vertebral body and lateral masses and a disc pressure sensor. Experimental conditions were simulated with cervical spine finite element model FSUs (GHBMC M50 version 5.0). The mean kinematics, vertebral strains, and disc pressures were compared to experimental results. The shear force-displacement response typically demonstrated a toe region followed by a linear response, with higher stiffness in anterior shear relative to lateral and posterior shear. Compressive axial preload decreased posterior and lateral shear stiffness and increased initial anterior shear stiffness. Load transmission patterns and kinematics suggest the facet joints play a key role in limiting anterior shear while the disc governs motion in posterior shear. The main cervical spine shear responses and trends are faithfully predicted by the GHBMC cervical spine model. These basic cervical spine biomechanics and the computational model can provide insight into mechanisms for facet dislocation in high severity impacts, and tissue distraction in low severity impacts.
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Affiliation(s)
- T Whyte
- Orthopaedic and Injury Biomechanics Group, Departments of Mechanical Engineering and Orthopaedics, The School of Biomedical Engineering and International Collaboration on Repair Discoveries, University of British Columbia, Vancouver, BC V6T 1Z4, Canada; Neuroscience Research Australia, Margarete Ainsworth Building, Barker Street, Randwick, NSW 2031, Australia
| | - J B Barker
- Department of Mechanical and Mechatronics Engineering, University of Waterloo, 200 University Avenue W, Waterloo, ON N2 L 3G1, Canada
| | - D S Cronin
- Department of Mechanical and Mechatronics Engineering, 200 University Avenue W, Waterloo, ON N2 L 3G1, Canada
| | - G A Dumas
- Department of Mechanical and Materials Engineering, Queen's University, 130 Stuart Street, Kingston, ON K7 L 3N6, Canada
| | - L-P Nolte
- ARTORG Center for Biomedical Engineering Research, University of Bern, Freiburgstrasse 3, Bern 3010, Switzerland
| | - P A Cripton
- Orthopaedic and Injury Biomechanics Group, Departments of Mechanical Engineering and Orthopaedics, The School of Biomedical Engineering and International Collaboration on Repair Discoveries, University of British Columbia, 6250 Applied Science Lane, Vancouver, BC V6T 1Z4, Canada
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Melnyk A, Whyte T, Thomson V, Marion T, Yamamoto S, Street J, Oxland TR, Cripton PA. The Effect of Compression Applied Through Constrained Lateral Eccentricity on the Failure Mechanics and Flexibility of the Human Cervical Spine. J Biomech Eng 2020; 142:1084015. [PMID: 32451551 DOI: 10.1115/1.4047342] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2019] [Indexed: 11/08/2022]
Abstract
In contrast to sagittal plane spine biomechanics, little is known about the response of the cervical spine to axial compression with lateral eccentricity of the applied force. This study evaluated the effect of lateral eccentricity on the kinetics, kinematics, canal occlusion, injuries, and flexibility of the cervical spine in translationally constrained axial impacts. Eighteen functional spinal units were subjected to flexibility tests before and after an impact. Impact axial compression was applied at one of three lateral eccentricity levels based on percentage of vertebral body width (low = 5%, medium = 50%, high = 150%). Injuries were graded by dissection. Correlations between intrinsic specimen properties and injury scores were examined for each eccentricity group. Low lateral force eccentricity produced predominantly bone injuries, clinically recognized as compression injuries, while medium and high eccentricity produced mostly contralateral ligament and/or disc injuries, an asymmetric pattern typical of lateral loading. Mean compression force at injury decreased with increasing lateral eccentricity (low = 3098 N, medium = 2337 N, and high = 683 N). Mean ipsilateral bending moments at injury were higher at medium (28.3 N·m) and high (22.9 N·m) eccentricity compared to low eccentricity specimens (0.1 N·m), p < 0.05. Ipsilateral bony injury was related to vertebral body area (VBA) (r = -0.974, p = 0.001) and disc degeneration (r = 0.851, p = 0.032) at medium eccentricity. Facet degeneration was correlated with central bony injury at high eccentricity (r = 0.834, p = 0.036). These results deepen cervical spine biomechanics knowledge in circumstances with coronal plane loads.
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Affiliation(s)
- Angela Melnyk
- Orthopaedic and Injury Biomechanics Group, Department of Mechanical Engineering, University of British Columbia, 818 W 10th Ave., Vancouver, BC V5Z 1M9, Canada; Orthopaedic and Injury Biomechanics Group, Department of Orthopaedics, University of British Columbia, 818 W 10th Ave., Vancouver, BC V5Z 1M9, Canada; International Collaboration on Repair Discoveries (ICORD), University of British Columbia, 818 W 10th Ave., Vancouver, BC V5Z 1M9, Canada
| | - Tom Whyte
- Orthopaedic and Injury Biomechanics Group, Department of Mechanical Engineering, University of British Columbia, 818 W 10th Ave., Vancouver, BC V5Z 1M9, Canada; Orthopaedic and Injury Biomechanics Group, Department of Orthopaedics, University of British Columbia, 818 W 10th Ave., Vancouver, BC V5Z 1M9, Canada; International Collaboration on Repair Discoveries (ICORD), University of British Columbia, 818 W 10th Ave., Vancouver, BC V5Z 1M9, Canada
| | - Vanessa Thomson
- Orthopaedic and Injury Biomechanics Group, Department of Mechanical Engineering, University of British Columbia, 818 W 10th Ave., Vancouver, BC V5Z 1M9, Canada; Orthopaedic and Injury Biomechanics Group, Department of Orthopaedics, University of British Columbia, 818 W 10th Ave., Vancouver, BC V5Z 1M9, Canada; International Collaboration on Repair Discoveries (ICORD), University of British Columbia, 818 W 10th Ave., Vancouver, BC V5Z 1M9, Canada
| | - Travis Marion
- Combined Neurosurgical and Orthopaedic Spine Program, Department of Orthopaedics, University of British Columbia, 818 W 10th Ave., Vancouver, BC V5Z 1M9, Canada
| | - Shun Yamamoto
- Orthopaedic and Injury Biomechanics Group, Department of Mechanical Engineering, University of British Columbia, 818 W 10th Ave., Vancouver, BC V5Z 1M9, Canada; Orthopaedic and Injury Biomechanics Group, Department of Orthopaedics, University of British Columbia, 818 W 10th Ave., Vancouver, BC V5Z 1M9, Canada
| | - John Street
- Combined Neurosurgical and Orthopaedic Spine Program, Department of Orthopaedics, University of British Columbia, 818 W 10th Ave., Vancouver, BC V5Z 1M9, Canada; International Collaboration on Repair Discoveries (ICORD), University of British Columbia, 818 W 10th Ave., Vancouver, BC V5Z 1M9, Canada
| | - Thomas R Oxland
- Orthopaedic and Injury Biomechanics Group, Department of Mechanical Engineering, University of British Columbia, 818 W 10th Ave., Vancouver, BC V5Z 1M9, Canada; Orthopaedic and Injury Biomechanics Group, Department of Orthopaedics, University of British Columbia, 818 W 10th Ave., Vancouver, BC V5Z 1M9, Canada; International Collaboration on Repair Discoveries (ICORD), University of British Columbia, 818 W 10th Ave., Vancouver, BC V5Z 1M9, Canada; Combined Neurosurgical and Orthopaedic Spine Program, Department of Orthopaedics, University of British Columbia, 818 W 10th Ave., Vancouver, BC V5Z 1M9, Canada; School of Biomedical Engineering, University of British Columbia, 818 W 10th Ave., Vancouver, BC V5Z 1M9, Canada
| | - Peter A Cripton
- Orthopaedic and Injury Biomechanics Group, Department of Mechanical Engineering, University of British Columbia, 818 W 10th Ave., Vancouver, BC V5Z 1M9, Canada; Orthopaedic and Injury Biomechanics Group, Department of Orthopaedics, University of British Columbia, 818 W 10th Ave., Vancouver, BC V5Z 1M9, Canada; International Collaboration on Repair Discoveries (ICORD), University of British Columbia, 818 W 10th Ave., Vancouver, BC V5Z 1M9, Canada; School of Biomedical Engineering, University of British Columbia, 818 W 10th Ave., Vancouver, BC V5Z 1M9, Canada
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Whyte T, Melnyk AD, Van Toen C, Yamamoto S, Street J, Oxland TR, Cripton PA. A neck compression injury criterion incorporating lateral eccentricity. Sci Rep 2020; 10:7114. [PMID: 32346007 PMCID: PMC7189232 DOI: 10.1038/s41598-020-63974-w] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/03/2019] [Accepted: 04/03/2020] [Indexed: 11/08/2022] Open
Abstract
There is currently no established injury criterion for the spine in compression with lateral load components despite this load combination commonly contributing to spinal injuries in rollover vehicle crashes, falls and sports. This study aimed to determine an injury criterion and accompanying tolerance values for cervical spine segments in axial compression applied with varying coronal plane eccentricity. Thirty-three human cadaveric functional spinal units were subjected to axial compression at three magnitudes of lateral eccentricity of the applied force. Injury was identified by high-speed video and graded by spine surgeons. Linear regression was used to define neck injury tolerance values based on a criterion incorporating coronal plane loads accounting for specimen sex, age, size and bone density. Larger coronal plane eccentricity at injury was associated with smaller resultant coronal plane force. The level of coronal plane eccentricity at failure appears to distinguish between the types of injuries sustained, with hard tissue structure injuries more common at low levels of eccentricity and soft tissue structure injuries more common at high levels of eccentricity. There was no relationship between axial force and lateral bending moment at injury which has been previously proposed as an injury criterion. These results provide the foundation for designing and evaluating strategies and devices for preventing severe spinal injuries.
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Affiliation(s)
- Tom Whyte
- Orthopaedic and Injury Biomechanics Group, Departments of Mechanical Engineering and Orthopaedics, University of British Columbia, 818 W 10th Ave, Vancouver, BC, V5Z 1M9, Canada
- International Collaboration on Repair Discoveries (ICORD), University of British Columbia, Vancouver, BC, V6T 1Z4, Canada
| | - Angela D Melnyk
- Orthopaedic and Injury Biomechanics Group, Departments of Mechanical Engineering and Orthopaedics, University of British Columbia, 818 W 10th Ave, Vancouver, BC, V5Z 1M9, Canada
- International Collaboration on Repair Discoveries (ICORD), University of British Columbia, Vancouver, BC, V6T 1Z4, Canada
| | - Carolyn Van Toen
- Orthopaedic and Injury Biomechanics Group, Departments of Mechanical Engineering and Orthopaedics, University of British Columbia, 818 W 10th Ave, Vancouver, BC, V5Z 1M9, Canada
- International Collaboration on Repair Discoveries (ICORD), University of British Columbia, Vancouver, BC, V6T 1Z4, Canada
| | - Shun Yamamoto
- Orthopaedic and Injury Biomechanics Group, Departments of Mechanical Engineering and Orthopaedics, University of British Columbia, 818 W 10th Ave, Vancouver, BC, V5Z 1M9, Canada
- International Collaboration on Repair Discoveries (ICORD), University of British Columbia, Vancouver, BC, V6T 1Z4, Canada
| | - John Street
- International Collaboration on Repair Discoveries (ICORD), University of British Columbia, Vancouver, BC, V6T 1Z4, Canada
- Combined Neurosurgical and Orthopaedic Spine Program, Department of Orthopaedics, University of British Columbia, Vancouver, V6T 1Z4, Canada
| | - Thomas R Oxland
- Orthopaedic and Injury Biomechanics Group, Departments of Mechanical Engineering and Orthopaedics, University of British Columbia, 818 W 10th Ave, Vancouver, BC, V5Z 1M9, Canada
- International Collaboration on Repair Discoveries (ICORD), University of British Columbia, Vancouver, BC, V6T 1Z4, Canada
- Combined Neurosurgical and Orthopaedic Spine Program, Department of Orthopaedics, University of British Columbia, Vancouver, V6T 1Z4, Canada
- School of Biomedical Engineering, University of British Columbia, Vancouver, BC, V6T 1Z4, Canada
| | - Peter A Cripton
- Orthopaedic and Injury Biomechanics Group, Departments of Mechanical Engineering and Orthopaedics, University of British Columbia, 818 W 10th Ave, Vancouver, BC, V5Z 1M9, Canada.
- International Collaboration on Repair Discoveries (ICORD), University of British Columbia, Vancouver, BC, V6T 1Z4, Canada.
- School of Biomedical Engineering, University of British Columbia, Vancouver, BC, V6T 1Z4, Canada.
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Quarrington RD, Costi JJ, Freeman BJC, Jones CF. The effect of axial compression and distraction on cervical facet mechanics during anterior shear, flexion, axial rotation, and lateral bending motions. J Biomech 2018; 83:205-213. [PMID: 30554817 DOI: 10.1016/j.jbiomech.2018.11.047] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/25/2018] [Revised: 11/21/2018] [Accepted: 11/27/2018] [Indexed: 11/29/2022]
Abstract
The subaxial cervical facets are important load-bearing structures, yet little is known about their mechanical response during physiological or traumatic intervertebral motion. Facet loading likely increases when intervertebral motions are superimposed with axial compression forces, increasing the risk of facet fracture. The aim of this study was to measure the mechanical response of the facets when intervertebral axial compression or distraction is superimposed on constrained, non-destructive shear, bending and rotation motions. Twelve C6/C7 motion segments (70 ± 13 yr, nine male) were subjected to constrained quasi-static anterior shear (1 mm), axial rotation (4°), flexion (10°), and lateral bending (5°) motions. Each motion was superimposed with three axial conditions: (1) 50 N compression; (2) 300 N compression (simulating neck muscle contraction); and, (3) 2.5 mm distraction. Angular deflections, and principal and shear surface strains, of the bilateral C6 inferior facets were calculated from motion-capture data and rosette strain gauges, respectively. Linear mixed-effects models (α = 0.05) assessed the effect of axial condition. Minimum principal and maximum shear strains were largest in the compressed condition for all motions except for maximum principal strains during axial rotation. For right axial rotation, maximum principal strains were larger for the contralateral facets, and minimum principal strains were larger for the left facets, regardless of axial condition. Sagittal deflections were largest in the compressed conditions during anterior shear and lateral bending motions, when adjusted for facet side.
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Affiliation(s)
- Ryan D Quarrington
- School of Mechanical Engineering, The University of Adelaide, South Australia, Australia; Centre for Orthopaedic & Trauma Research, Adelaide Medical School, The University of Adelaide, South Australia, Australia; Adelaide Spinal Research Group, Adelaide Medical School, The University of Adelaide, South Australia, Australia.
| | - John J Costi
- Biomechanics and Implants Research Group, The Medical Device Research Institute, College of Science and Engineering, Flinders University, South Australia, Australia.
| | - Brian J C Freeman
- The Spinal Injuries Unit, Royal Adelaide Hospital, Adelaide, Australia; Centre for Orthopaedic & Trauma Research, Adelaide Medical School, The University of Adelaide, South Australia, Australia; Adelaide Spinal Research Group, Adelaide Medical School, The University of Adelaide, South Australia, Australia.
| | - Claire F Jones
- Centre for Orthopaedic & Trauma Research, Adelaide Medical School, The University of Adelaide, South Australia, Australia; Adelaide Spinal Research Group, Adelaide Medical School, The University of Adelaide, South Australia, Australia; School of Mechanical Engineering, The University of Adelaide, South Australia, Australia.
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8
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Quantitative evaluation of facet deflection, stiffness, strain and failure load during simulated cervical spine trauma. J Biomech 2018; 72:116-124. [DOI: 10.1016/j.jbiomech.2018.02.036] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/05/2017] [Revised: 01/21/2018] [Accepted: 02/28/2018] [Indexed: 01/08/2023]
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9
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Van Toen C, Street J, Oxland TR, Cripton PA. Cervical spine injuries and flexibilities following axial impact with lateral eccentricity. EUROPEAN SPINE JOURNAL : OFFICIAL PUBLICATION OF THE EUROPEAN SPINE SOCIETY, THE EUROPEAN SPINAL DEFORMITY SOCIETY, AND THE EUROPEAN SECTION OF THE CERVICAL SPINE RESEARCH SOCIETY 2014; 24:136-47. [PMID: 25344091 DOI: 10.1007/s00586-014-3612-4] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/12/2013] [Revised: 09/30/2014] [Accepted: 10/01/2014] [Indexed: 10/24/2022]
Abstract
PURPOSE Determine the effects of dynamic injurious axial compression applied at various lateral eccentricities (lateral distance to the centre of the spine) on mechanical flexibilities and structural injury patterns of the cervical spine. METHODS 13 three-vertebra human cadaver cervical spine specimens (6 C3-5, 3 C4-6, 2 C5-7, 2 C6-T1) were subjected to pure moment flexibility tests (±1.5 Nm) before and after impact trauma was applied in two groups: low and high lateral eccentricity (1 and 150 % of the lateral diameter of the vertebral body, respectively). Relative range of motion (ROM) and relative neutral zone (NZ) were calculated as the ratio of post and pre-trauma values. Injuries were diagnosed by a spine surgeon and scored. Classification functions were developed using discriminant analysis. RESULTS Low and high eccentric loading resulted in primarily bony fractures and soft tissue injuries, respectively. Axial impacts with high lateral eccentricities resulted in greater spinal motion in lateral bending [median relative ROM 3.5 (interquartile range, IQR 2.3) vs. 1.4 (IQR 0.5) and median relative NZ 4.7 (IQR 3.7) vs. 2.3 (IQR 1.1)] and in axial rotation [median relative ROM 5.3 (IQR 13.7) vs. 1.3 (IQR 0.5), p < 0.05 for all comparisons] than those that resulted from low eccentricity impacts. The developed classification functions had 92 % classification accuracy. CONCLUSIONS Dynamic axial compression loading of the cervical spine with high lateral eccentricities produced primarily soft tissue injuries resulting in more post-injury spinal flexibility in lateral bending and axial rotation than that associated with the bony fractures resulting from low eccentricity impacts.
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Affiliation(s)
- C Van Toen
- Orthopaedic and Injury Biomechanics Group, Departments of Mechanical Engineering and Orthopaedics, University of British Columbia, 6250 Applied Science Lane, Vancouver, BC, V6T 1Z4, Canada
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