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Quarrington RD, Bauze R, Jones CF. Kinematics, kinetics, and new insights from a contemporary analysis of the first experiments to produce cervical facet dislocations in the laboratory. JOR Spine 2024; 7:e1336. [PMID: 38803524 PMCID: PMC11129552 DOI: 10.1002/jsp2.1336] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/27/2023] [Revised: 03/24/2024] [Accepted: 04/14/2024] [Indexed: 05/29/2024] Open
Abstract
Background The first experimental study to produce cervical facet dislocation (CFD) in cadaver specimens captured the vertebral motions and axial forces that are important for understanding the injury mechanics. However, these data were not reported in the original manuscript, nor been presented in the limited subsequent studies of experimental CFD. Therefore, the aim of this study was to re-examine the analog data from the first experimental study to determine the local and global spinal motions, and applied axial force, at and preceding CFD. Methods In the original study, quasistatic axial loading was applied to 14 cervical spines by compressing them between two metal plates. Specimens were fixed caudally via a steel spindle positioned within the spinal canal and a bone pin through the inferior-most vertebral body. Global rotation of the occiput was restricted but its anterior translation was unconstrained. The instant of CFD was identified on sagittal cineradiograph films (N = 10), from which global and intervertebral kinematics were also calculated. Corresponding axial force data (N = 6) were extracted, and peak force and force at the instant of injury were determined. Results CFD occurred in eight specimens, with an intervertebral flexion angle of 34.8 ± 5.6 degrees, and a 3.1 ± 1.9 mm increase in anterior translation, at the injured level. For seven specimens, CFD was produced at the level of transition from upper neck lordosis to lower neck kyphosis. Five specimens with force data underwent CFD at 545 ± 147 N, preceded by a peak axial force (755 ± 233 N) that appeared to coincide with either fracture or soft tissue failure. Conclusions Re-examining this rich dataset has provided quantitative evidence that small axial compression forces, combined with anterior eccentricity and upper neck extension, can cause flexion and shear in the lower neck, leading to soft tissue rupture and CFD.
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Affiliation(s)
- Ryan D. Quarrington
- Adelaide Spinal Research Group, Centre for Orthopaedic & Trauma Research, Faculty of Health and Medical SciencesThe University of AdelaideAdelaideSouth AustraliaAustralia
- Adelaide Medical SchoolThe University of AdelaideAdelaideSouth AustraliaAustralia
- School of Electrical and Mechanical EngineeringThe University of AdelaideAdelaideSouth AustraliaAustralia
| | - Robert Bauze
- Department of Orthopaedics and TraumaRoyal Adelaide Hospital and The Queen Elizabeth HospitalAdelaideSouth AustraliaAustralia
- Nuffield Department of Orthopaedic SurgeryUniversity of OxfordOxfordUK
| | - Claire F. Jones
- Adelaide Spinal Research Group, Centre for Orthopaedic & Trauma Research, Faculty of Health and Medical SciencesThe University of AdelaideAdelaideSouth AustraliaAustralia
- School of Electrical and Mechanical EngineeringThe University of AdelaideAdelaideSouth AustraliaAustralia
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Yamamoto S, Dias L, Street J, Cripton PA, Oxland TR. Anteroposterior shear stiffness of the upper thoracic spine at quasi-static and dynamic loading rates-An in vitro biomechanical study. J Orthop Res 2022; 40:1687-1694. [PMID: 34669215 DOI: 10.1002/jor.25196] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/06/2021] [Revised: 09/15/2021] [Accepted: 09/30/2021] [Indexed: 02/04/2023]
Abstract
To evaluate the biomechanical properties of the upper thoracic spine in anterior-posterior shear loading at various displacement rates. These data broaden our understanding of thoracic spine biomechanics and inform efforts to model the spine and spinal cord injuries. Seven T1-T2 thoracic functional spinal units were loaded non-destructively by a pure shear force up to 200 N, starting from a neutral posture. Tests were run in both posterior and anterior directions, at displacement rates of 1, 10, and 100 mm/s. The three-dimensional motion of the specimen was recorded at 1000 Hz. Individual and averaged load-displacement curves were generated and specimen stiffnesses were calculated. Due to a nonlinear response of the specimens, stiffness was defined separately for both the lower half and the upper half of the specimen range of motion. Specimens were significantly stiffer in the anterior direction than in the posterior direction, across all rates. At low displacements, the anterior stiffness averaged 230 N/mm, 76% higher than the low displacement posterior stiffness of 131 N/mm. At high displacements, anterior stiffness averaged 258 N/mm, 51% stiffer than the high displacement posterior stiffness of 171 N/mm. Shear displacement rate had a small effect on the load response, with the 100 mm/s rate causing a mildly stiffer response at low displacements in the anterior direction. Overall, the load-displacement response exhibited pseudo-quadratic behavior at 1 and 10 mm/s but became more linear at 100 mm/s. The shear stiffness in the upper thoracic spine is greatest in the anterior loading direction, being 51%-76% greater than posterior, most likely due to facet interactions. The effect of the shear displacement rate is low.
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Affiliation(s)
- Shun Yamamoto
- Orthopaedic and Injury Biomechanics Group, University of British Columbia, Vancouver, British Columbia, Canada.,Departments of Mechanical Engineering and Orthopaedics, University of British Columbia, Vancouver, British Columbia, Canada.,International Collaboration on Repair Discoveries (ICORD), University of British Columbia, Vancouver, British Columbia, Canada.,Department of Orthopaedic Surgery, Jikei University School of Medicine, Minato, Tokyo, Japan
| | - Luis Dias
- Orthopaedic and Injury Biomechanics Group, University of British Columbia, Vancouver, British Columbia, Canada.,International Collaboration on Repair Discoveries (ICORD), University of British Columbia, Vancouver, British Columbia, Canada
| | - John Street
- Orthopaedic and Injury Biomechanics Group, University of British Columbia, Vancouver, British Columbia, Canada.,Departments of Mechanical Engineering and Orthopaedics, University of British Columbia, Vancouver, British Columbia, Canada.,International Collaboration on Repair Discoveries (ICORD), University of British Columbia, Vancouver, British Columbia, Canada
| | - Peter A Cripton
- Orthopaedic and Injury Biomechanics Group, University of British Columbia, Vancouver, British Columbia, Canada.,International Collaboration on Repair Discoveries (ICORD), University of British Columbia, Vancouver, British Columbia, Canada.,School of Biomedical Engineering, University of British Columbia, Vancouver, British Columbia, Canada
| | - Thomas R Oxland
- Orthopaedic and Injury Biomechanics Group, University of British Columbia, Vancouver, British Columbia, Canada.,Departments of Mechanical Engineering and Orthopaedics, University of British Columbia, Vancouver, British Columbia, Canada.,International Collaboration on Repair Discoveries (ICORD), University of British Columbia, Vancouver, British Columbia, Canada
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Whyte T, Lind E, Richards A, Eager D, Bilston LE, Brown J. Neck Loads During Head-First Entries into Trampoline Dismount Foam Pits: Considerations for Trampoline Park Safety. Ann Biomed Eng 2022; 50:691-702. [PMID: 35381914 PMCID: PMC9079033 DOI: 10.1007/s10439-022-02945-w] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/15/2021] [Accepted: 03/09/2022] [Indexed: 11/21/2022]
Abstract
Serious cervical spine injuries have been documented from falls into foam pits at trampoline parks. To address the lack of evidence on how foam pits should be designed for mitigating neck injury risk, this study aimed to quantify neck loads during head-first entry into varying foam pit designs. An instrumented Hybrid III anthropomorphic test device was dropped head-first from a height of up to 1.5 m into three differently constructed foam pits, each using a different mechanism to prevent direct contact between the falling person and the floor (foam slab, trampoline or net bed). Measured neck loads were compared to published injury reference values. In the simplest, foam-only pit design, increasing foam depth tended to reduce peak compressive force. At least one injury assessment reference metric was exceeded in all pit conditions tested for 1.5 m falls, most commonly the time-dependent neck compression criterion. The results highlight the importance of adequate foam depth in combination with appropriate pit design in minimizing injury risk. The risk of cervical spine injury may not be reduced sufficiently with current foam pit designs.
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Affiliation(s)
- Tom Whyte
- Neuroscience Research Australia, Margarete Ainsworth Building, 139 Barker St, Randwick, NSW 2031 Australia
- School of Medical Sciences, Faculty of Medicine, The University of New South Wales, Sydney, NSW 2052 Australia
- The George Institute for Global Health, Level 5/1 King St, Newtown, NSW 2042 Australia
| | - Edward Lind
- Neuroscience Research Australia, Margarete Ainsworth Building, 139 Barker St, Randwick, NSW 2031 Australia
- School of Mechanical and Mechatronic Engineering, Faculty of Engineering and Information Technology, University of Technology Sydney, 15 Broadway, Ultimo, NSW 2007 Australia
| | - Adam Richards
- Mr Trampoline Pty Ltd, 966-968 & 972 Dandenong Road, Carnegie, VIC 3163 Australia
| | - David Eager
- School of Mechanical and Mechatronic Engineering, Faculty of Engineering and Information Technology, University of Technology Sydney, 15 Broadway, Ultimo, NSW 2007 Australia
| | - Lynne E. Bilston
- Neuroscience Research Australia, Margarete Ainsworth Building, 139 Barker St, Randwick, NSW 2031 Australia
- Prince of Wales Clinical School, Faculty of Medicine, The University of New South Wales, Sydney, NSW 2052 Australia
| | - Julie Brown
- Neuroscience Research Australia, Margarete Ainsworth Building, 139 Barker St, Randwick, NSW 2031 Australia
- School of Medical Sciences, Faculty of Medicine, The University of New South Wales, Sydney, NSW 2052 Australia
- The George Institute for Global Health, Level 5/1 King St, Newtown, NSW 2042 Australia
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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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Silvestros P, Pizzolato C, Lloyd DG, Preatoni E, Gill HS, Cazzola D. Electromyography-Assisted Neuromusculoskeletal Models Can Estimate Physiological Muscle Activations and Joint Moments Across the Neck Before Impacts. J Biomech Eng 2022; 144:1120603. [PMID: 34557891 DOI: 10.1115/1.4052555] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/13/2021] [Indexed: 01/20/2023]
Abstract
Knowledge of neck muscle activation strategies before sporting impacts is crucial for investigating mechanisms of severe spinal injuries. However, measurement of muscle activations during impacts is experimentally challenging and computational estimations are not often guided by experimental measurements. We investigated neck muscle activations before impacts with the use of electromyography (EMG)-assisted neuromusculoskeletal models. Kinematics and EMG recordings from four major neck muscles of a rugby player were experimentally measured during rugby activities. A subject-specific musculoskeletal model was created with muscle parameters informed from MRI measurements. The model was used in the calibrated EMG-informed neuromusculoskeletal modeling toolbox and three neural solutions were compared: (i) static optimization (SO), (ii) EMG-assisted (EMGa), and (iii) MRI-informed EMG-assisted (EMGaMRI). EMGaMRI and EMGa significantly (p < 0.01) outperformed SO when tracking cervical spine net joint moments from inverse dynamics in flexion/extension (RMSE = 0.95, 1.14, and 2.32 N·m) but not in lateral bending (RMSE = 1.07, 2.07, and 0.84 N·m). EMG-assisted solutions generated physiological muscle activation patterns and maintained experimental cocontractions significantly (p < 0.01) outperforming SO, which was characterized by saturation and nonphysiological "on-off" patterns. This study showed for the first time that physiological neck muscle activations and cervical spine net joint moments can be estimated without assumed a priori objective criteria before impacts. Future studies could use this technique to provide detailed initial loading conditions for theoretical simulations of neck injury during impacts.
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Affiliation(s)
- Pavlos Silvestros
- Department for Health, Centre for Analysis of Motion and Entertainment Research and Application (CAMERA), University of Bath, Bath BA2 7AY, UK
| | - Claudio Pizzolato
- School of Allied Health Sciences, Griffith Centre of Biomedical and Rehabilitation Engineering (GCORE), Menzies Health Institute Griffith University, Gold Coast, Queensland 4222, Australia
| | - David G Lloyd
- School of Allied Health Sciences, Griffith Centre of Biomedical and Rehabilitation Engineering (GCORE), Menzies Health Institute Griffith University, Gold Coast, Queensland 4222, Australia
| | - Ezio Preatoni
- Department for Health, University of Bath, Bath BA2 7AY, UK
| | - Harinderjit S Gill
- Centre for Therapeutic Innovation, Department of Mechanical Engineering, University of Bath, Bath BA2 7AY, UK
| | - Dario Cazzola
- Department for Health, Centre for Analysis of Motion and Entertainment Research and Application (CAMERA), University of Bath, Bath BA2 7AY, UK
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Beauséjour MH, Petit Y, Wagnac É, Melot A, Troude L, Arnoux PJ. Cervical spine injury response to direct rear head impact. Clin Biomech (Bristol, Avon) 2022; 92:105552. [PMID: 34999391 DOI: 10.1016/j.clinbiomech.2021.105552] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/23/2021] [Revised: 09/29/2021] [Accepted: 12/14/2021] [Indexed: 02/07/2023]
Abstract
BACKGROUND Direct rear head impact can occur during falls, road accidents, or sports accidents. They induce anterior shear, flexion and compression loads suspected to cause flexion-distraction injuries at the cervical spine. However, post-mortem human subject experiments mostly focus on sled impacts and not direct head impacts. METHODS Six male cadavers were subjected to a direct rear head impact of 3.5 to 5.5 m/s with a 40 kg impactor. The subjects were equipped with accelerometers at the forehead, mouth and sternum. High-speed cameras and stereography were used to track head displacements. Head range of motion in flexion-extension was measured before and after impact for four cadavers. The injuries were assessed from CT scan images and dissection. FINDINGS Maximum head rotation was between 43 degrees and 78 degrees, maximum cranial-caudal displacement between -12 mm and - 196 mm, and antero-posterior displacement between 90 mm and 139 mm during the impact. Four subjects had flexion-distraction injuries. Anterior vertebral osteophyte identification showed that fractures occurred at adjacent levels of osteophytic bridges. The other two subjects had no anterior osteophytes and suffered from C2 fracture, and one subject also had a C1-C2 subluxation. C6-C7 was the most frequently injured spinal level. INTERPRETATION Anterior vertebral osteophytes appear to influence the type and position of injuries. Osteophytes would seem to provide stability in flexion for the osteoarthritic cervical spine, but to also lead to stress concentration in levels adjacent to the osteophytes. Clinical management of patients presenting with osteophytes fracture should include neck immobilization and careful follow-up to ensure bone healing.
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Affiliation(s)
- Marie-Hélène Beauséjour
- Department of Mechanical Engineering, École de technologie supérieure, 1100 Notre-Dame Street West, H3C 1K3, Montreal, Quebec, Canada; Research Center, Hôpital du Sacré-Coeur de Montréal, 5400 Boulevard Gouin, H4J 1C5, Montreal, Quebec, Canada; International Laboratory on Spine Imaging and Biomechanics, France and Canada; Laboratoire de Biomécanique Appliquée-Université Gustave-Eiffel, Aix-Marseille Université, UMR T24, 51 boulevard Pierre Dramard, 13015 Marseille, France
| | - Yvan Petit
- Department of Mechanical Engineering, École de technologie supérieure, 1100 Notre-Dame Street West, H3C 1K3, Montreal, Quebec, Canada; Research Center, Hôpital du Sacré-Coeur de Montréal, 5400 Boulevard Gouin, H4J 1C5, Montreal, Quebec, Canada; International Laboratory on Spine Imaging and Biomechanics, France and Canada.
| | - Éric Wagnac
- Department of Mechanical Engineering, École de technologie supérieure, 1100 Notre-Dame Street West, H3C 1K3, Montreal, Quebec, Canada; Research Center, Hôpital du Sacré-Coeur de Montréal, 5400 Boulevard Gouin, H4J 1C5, Montreal, Quebec, Canada; International Laboratory on Spine Imaging and Biomechanics, France and Canada
| | - Anthony Melot
- International Laboratory on Spine Imaging and Biomechanics, France and Canada; Laboratoire de Biomécanique Appliquée-Université Gustave-Eiffel, Aix-Marseille Université, UMR T24, 51 boulevard Pierre Dramard, 13015 Marseille, France; Hôpital privé Clairval, 317 boulevard du Redon, 13009 Marseille, France
| | - Lucas Troude
- Neurosurgery, CHU Nord Marseille, Chemin des Bourrely, cedex 20, 13015 Marseille, France
| | - Pierre-Jean Arnoux
- International Laboratory on Spine Imaging and Biomechanics, France and Canada; Laboratoire de Biomécanique Appliquée-Université Gustave-Eiffel, Aix-Marseille Université, UMR T24, 51 boulevard Pierre Dramard, 13015 Marseille, France
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Jung SH, Hwang JM, Kim CH. Inversion Table Fall Injury, the Phantom Menace: Three Case Reports on Cervical Spinal Cord Injury. Healthcare (Basel) 2021; 9:healthcare9050492. [PMID: 33922070 PMCID: PMC8143462 DOI: 10.3390/healthcare9050492] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2021] [Revised: 04/14/2021] [Accepted: 04/19/2021] [Indexed: 12/13/2022] Open
Abstract
Background: An inversion device, which is used to suspend one’s body and perform traction therapy, was introduced as an inversion table under the name of “Geokkuri” in South Korea. Fall injuries while hanging on inversion tables are among the most devastating spine injuries, as the likelihood of severe neurological sequelae such as tetraplegia increases. However, its enormous danger has been overlooked and this devastating injury has become a common clinical entity over time. The limited number of studies reported imply the lack of interest of researchers in these injuries. We reviewed three cases of spinal cord injury sustained on inversion tables in different environments and report the potential danger associated with the use of inversion tables to facilitate a safer exercise environment.
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Affiliation(s)
- Seung-Hwan Jung
- Department of Rehabilitation Medicine, Kyungpook National University Hospital, Daegu 41944, Korea;
| | - Jong-Moon Hwang
- Department of Rehabilitation Medicine, Kyungpook National University Hospital, Daegu 41944, Korea;
- Department of Rehabilitation Medicine, School of Medicine, Kyungpook National University, Daegu 41944, Korea
- Correspondence: (J.-M.H.); (C.-H.K.)
| | - Chul-Hyun Kim
- Department of Rehabilitation Medicine, Kyungpook National University Hospital, Daegu 41944, Korea;
- Department of Rehabilitation Medicine, School of Medicine, Kyungpook National University, Daegu 41944, Korea
- Correspondence: (J.-M.H.); (C.-H.K.)
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