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Harmon JN, Hyde JE, Jensen DE, D'cessare EC, Odarenko AA, Bruce MF, Khaing ZZ. Quantifying injury expansion in the cervical spinal cord with intravital ultrafast contrast-enhanced ultrasound imaging. Exp Neurol 2024; 374:114681. [PMID: 38199511 PMCID: PMC10922898 DOI: 10.1016/j.expneurol.2024.114681] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2023] [Revised: 12/08/2023] [Accepted: 01/02/2024] [Indexed: 01/12/2024]
Abstract
Spinal cord injury is characterized by hemodynamic disruption at the injury epicenter and hypoperfusion in the penumbra, resulting in progressive ischemia and cell death. This degenerative secondary injury process has been well-described, though mostly using ex vivo or depth-limited optical imaging techniques. Intravital contrast-enhanced ultrasound enables longitudinal, quantitative evaluation of anatomical and hemodynamic changes in vivo through the entire spinal parenchyma. Here, we used ultrasound imaging to visualize and quantify subacute injury expansion (through 72 h post-injury) in a rodent cervical contusion model. Significant intraparenchymal hematoma expansion was observed through 72 h post-injury (1.86 ± 0.17-fold change from acute, p < 0.05), while the volume of the ischemic deficit largely increased within 24 h post-injury (2.24 ± 0.27-fold, p < 0.05). Histology corroborated these findings; increased apoptosis, tissue and vessel loss, and sustained tissue hypoxia were observed at 72 h post-injury. Vascular resistance was significantly elevated in the remaining perfused tissue, likely due in part to deformation of the central sulcal artery nearest to the lesion site. In conjunction, substantial hyperemia was observed in all perilesional areas examined except the ipsilesional gray matter. This study demonstrates the utility of longitudinal ultrasound imaging as a quantitative tool for tracking injury progression in vivo.
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Affiliation(s)
- Jennifer N Harmon
- Department of Neurological Surgery, University of Washington, 1959 NE Pacific St., Seattle, WA, USA.
| | - Jeffrey E Hyde
- Department of Neurological Surgery, University of Washington, 1959 NE Pacific St., Seattle, WA, USA.
| | - Dylan E Jensen
- Department of Neurological Surgery, University of Washington, 1959 NE Pacific St., Seattle, WA, USA.
| | - Emma C D'cessare
- Department of Neurological Surgery, University of Washington, 1959 NE Pacific St., Seattle, WA, USA.
| | - Anton A Odarenko
- Department of Neurological Surgery, University of Washington, 1959 NE Pacific St., Seattle, WA, USA.
| | - Matthew F Bruce
- Applied Physics Laboratory, University of Washington, Seattle, WA, USA.
| | - Zin Z Khaing
- Department of Neurological Surgery, University of Washington, 1959 NE Pacific St., Seattle, WA, USA.
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2
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Dynamic changes in mechanical properties of the adult rat spinal cord after injury. Acta Biomater 2023; 155:436-448. [PMID: 36435440 DOI: 10.1016/j.actbio.2022.11.041] [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: 08/04/2022] [Revised: 11/06/2022] [Accepted: 11/18/2022] [Indexed: 11/25/2022]
Abstract
Spinal cord injury (SCI), a debilitating medical condition that can cause irreversible loss of neurons and permanent paralysis, currently has no cure. However, regenerative medicine may offer a promising treatment. Given that numerous regenerative strategies aim to deliver cells and materials in the form of tissue-engineered therapies, understanding and characterising the mechanical properties of the spinal cord tissue is very important. In this study, we have systematically characterised the spatiotemporal changes in elastic stiffness (elastic modulus, Pa) and viscosity (drop in peak force, %) of injured rat thoracic spinal cord tissues at distinct time points after crush injury using the indentation technique. Our results demonstrate that in comparison with uninjured spinal cord tissue, the injured tissues exhibited lower stiffness (median 3281 Pa versus 9632 Pa; P < 0.001) but demonstrated elevated viscosity (median 80% versus 57%; P < 0.001) at 3 days postinjury. Between 4 and 6 weeks after SCI, the overall viscoelastic properties of injured tissues returned to baseline values. At 12 weeks after SCI, in comparison with uninjured tissue, the injured spinal cord tissues displayed a significant increase in both elasticity (median 13698 Pa versus 9920 Pa; P < 0.001) and viscosity (median 64% versus 58%; P < 0.001). This work constitutes the first quantitative mapping of spatiotemporal changes in spinal cord tissue elasticity and viscosity in injured rats, providing a mechanical basis of the tissue for future studies on the development of biomaterials for SCI repair. STATEMENT OF SIGNIFICANCE: Spinal cord injury (SCI) is a devastating disease often leading to permanent paralysis. While enormous progress in understanding the molecular pathomechanisms of SCI has been made, the mechanical properties of injured spinal cord tissue have received considerably less attention. This study provides systematic characterization of the biomechanical evolution of rat spinal cord tissue after SCI using a microindentation test method. We find spinal cord tissue behaves significantly softer but more viscous immediately postinjury. As time passes, the lesion site gradually returns to baseline values and then displays pronounced increased viscoelastic properties. As host tissue mechanical properties are a crucial consideration for any biomaterial implanted into central nervous system, our results may have important implications for further studies of SCI repair.
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Malomo T, Allard Brown A, Bale K, Yung A, Kozlowski P, Heran M, Streijger F, Kwon BK. Quantifying Intraparenchymal Hemorrhage after Traumatic Spinal Cord Injury: A Review of Methodology. J Neurotrauma 2022; 39:1603-1635. [PMID: 35538847 DOI: 10.1089/neu.2021.0317] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023] Open
Abstract
Intraparenchymal hemorrhage (IPH) after a traumatic injury has been associated with poor neurological outcomes. Although IPH may result from the initial mechanical trauma, the blood and its breakdown products have potentially deleterious effects. Further, the degree of IPH has been correlated with injury severity and the extent of subsequent recovery. Therefore, accurate evaluation and quantification of IPH following traumatic spinal cord injury (SCI) is important to define treatments' effects on IPH progression and secondary neuronal injury. Imaging modalities, such as magnetic resonance imaging (MRI) and ultrasound (US), have been explored by researchers for the detection and quantification of IPH following SCI. Both quantitative and semiquantitative MRI and US measurements have been applied to objectively assess IPH following SCI, but the optimal methods for doing so are not well established. Studies in animal SCI models (rodent and porcine) have explored US and histological techniques in evaluating SCI and have demonstrated the potential to detect and quantify IPH. Newer techniques using machine learning algorithms (such as convolutional neural networks [CNN]) have also been studied to calculate IPH volume and have yielded promising results. Despite long-standing recognition of the potential pathological significance of IPH within the spinal cord, quantifying IPH with MRI or US is a relatively new area of research. Further studies are warranted to investigate their potential use. Here, we review the different and emerging quantitative MRI, US, and histological approaches used to detect and quantify IPH following SCI.
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Affiliation(s)
- Toluyemi Malomo
- International Collaboration on Repair Discoveries, Division of Neuroradiology, Vancouver General Hospital, University of British Columbia, Vancouver, British Columbia, Canada
| | - Aysha Allard Brown
- International Collaboration on Repair Discoveries, Division of Neuroradiology, Vancouver General Hospital, University of British Columbia, Vancouver, British Columbia, Canada
| | - Kirsten Bale
- International Collaboration on Repair Discoveries, Division of Neuroradiology, Vancouver General Hospital, University of British Columbia, Vancouver, British Columbia, Canada.,UBC MRI Research Center, Division of Neuroradiology, Vancouver General Hospital, University of British Columbia, Vancouver, British Columbia, Canada
| | - Andrew Yung
- International Collaboration on Repair Discoveries, Division of Neuroradiology, Vancouver General Hospital, University of British Columbia, Vancouver, British Columbia, Canada.,UBC MRI Research Center, Division of Neuroradiology, Vancouver General Hospital, University of British Columbia, Vancouver, British Columbia, Canada
| | - Piotr Kozlowski
- International Collaboration on Repair Discoveries, Division of Neuroradiology, Vancouver General Hospital, University of British Columbia, Vancouver, British Columbia, Canada.,UBC MRI Research Center, Division of Neuroradiology, Vancouver General Hospital, University of British Columbia, Vancouver, British Columbia, Canada
| | - Manraj Heran
- Department of Radiology, Division of Neuroradiology, Vancouver General Hospital, University of British Columbia, Vancouver, British Columbia, Canada
| | - Femke Streijger
- International Collaboration on Repair Discoveries, Division of Neuroradiology, Vancouver General Hospital, University of British Columbia, Vancouver, British Columbia, Canada
| | - Brian K Kwon
- International Collaboration on Repair Discoveries, Division of Neuroradiology, Vancouver General Hospital, University of British Columbia, Vancouver, British Columbia, Canada.,Vancouver Spine Surgery Institute, Department of Orthopaedics, and Division of Neuroradiology, Vancouver General Hospital, University of British Columbia, Vancouver, British Columbia, Canada
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Jin C, Zhu R, Xu ML, Zheng LD, Zeng HZ, Xie N, Cheng LM. Effect of Velocity and Contact Stress Area on the Dynamic Behavior of the Spinal Cord Under Different Testing Conditions. Front Bioeng Biotechnol 2022; 10:762555. [PMID: 35309983 PMCID: PMC8931460 DOI: 10.3389/fbioe.2022.762555] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/03/2021] [Accepted: 01/31/2022] [Indexed: 11/28/2022] Open
Abstract
Knowledge of the dynamic behavior of the spinal cord under different testing conditions is critical for our understanding of biomechanical mechanisms of spinal cord injury. Although velocity and contact stress area are known to affect external mechanical stress or energy upon sudden traumatic injury, quantitative investigation of the two clinically relevant biomechanical variables is limited. Here, freshly excised rat spinal-cord–pia-arachnoid constructs were tested through indentation using indenters of different sizes (radii: 0.25, 0.50, and 1.00 mm) at various loading rates ranging from 0.04 to 0.20 mm/s. This analysis found that the ex vivo specimen displayed significant nonlinear viscoelasticity at <10% of specimen thickness depth magnitudes. At higher velocity and larger contact stress area, the cord withstood a higher peak load and exhibited more sensitive mechanical relaxation responses (i.e., increasing amplitude and speed of the drop in peak load). Additionally, the cord became stiffer (i.e., increasing elastic modulus) and softer (i.e., decreasing elastic modulus) at a higher velocity and larger contact stress area, respectively. These findings will improve our understanding of the real-time complex biomechanics involved in traumatic spinal cord injury.
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Affiliation(s)
| | | | | | | | | | - Ning Xie
- *Correspondence: Ning Xie, ; Li-ming Cheng,
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Spinal cord injury in mice impacts central and peripheral pathology in a severity-dependent manner. Pain 2021; 163:1172-1185. [PMID: 34490852 DOI: 10.1097/j.pain.0000000000002471] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2021] [Accepted: 08/25/2021] [Indexed: 11/26/2022]
Abstract
ABSTRACT Chronic pain is a common medical complication experienced by those living with spinal cord injury (SCI) and leads to worsened quality of life. The pathophysiology of SCI pain is poorly understood, hampering the development of safe and efficacious therapeutics. We therefore sought to develop a clinically relevant model of SCI with a strong pain phenotype and characterize the central and peripheral pathology after injury. A contusion (50 kdyn) injury, with and without sustained compression (60 seconds) of the spinal cord, was carried out on female C57BL/6J mice. Mice with compression of the spinal cord exhibited significantly greater heat and mechanical hypersensitivity starting at 7 days post-injury, concomitant with reduced locomotor function, compared to those without compression. Immunohistochemical analysis of spinal cord tissue revealed significantly less myelin sparing and increased macrophage activation in mice with compression compared to those without. As measured by flow cytometry, immune cell infiltration and activation were significantly greater in the spinal cord (phagocytic myeloid cells and microglia) and dorsal root ganglia (Ly6C+ monocytes) following compression injury. We also decided to investigate the gastrointestinal microbiome, as it has been shown to be altered in SCI patients and has recently been shown to play a role in immune system maturation and pain. We found increased dysbiosis of the gastrointestinal microbiome in an injury severity-dependent manner. The use of this contusion-compression model of SCI may help advance the preclinical assessment of acute and chronic SCI pain and lead to a better understanding of mechanisms contributing to this pain.
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Watzlawick R, Antonic A, Sena ES, Kopp MA, Rind J, Dirnagl U, Macleod M, Howells DW, Schwab JM. Outcome heterogeneity and bias in acute experimental spinal cord injury: A meta-analysis. Neurology 2019; 93:e40-e51. [PMID: 31175207 DOI: 10.1212/wnl.0000000000007718] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/27/2018] [Accepted: 02/11/2019] [Indexed: 01/18/2023] Open
Abstract
OBJECTIVE To determine whether and to what degree bias and underestimated variability undermine the predictive value of preclinical research for clinical translation. METHODS We investigated experimental spinal cord injury (SCI) studies for outcome heterogeneity and the impact of bias. Data from 549 preclinical SCI studies including 9,535 animals were analyzed with meta-regression to assess the effect of various study characteristics and the quality of neurologic recovery. RESULTS Overall, the included interventions reported a neurobehavioral outcome improvement of 26.3% (95% confidence interval 24.3-28.4). Response to treatment was dependent on experimental modeling paradigms (neurobehavioral score, site of injury, and animal species). Applying multiple outcome measures was consistently associated with smaller effect sizes compared with studies applying only 1 outcome measure. More than half of the studies (51.2%) did not report blinded assessment, constituting a likely source of evaluation bias, with an overstated effect size of 7.2%. Assessment of publication bias, which extrapolates to identify likely missing data, suggested that between 2% and 41% of experiments remain unpublished. Inclusion of these theoretical missing studies suggested an overestimation of efficacy, reducing the effect sizes by between 0.9% and 14.3%. CONCLUSIONS We provide empirical evidence of prevalent bias in the design and reporting of experimental SCI studies, resulting in overestimation of the effectiveness. Bias compromises the internal validity and jeopardizes the successful translation of SCI therapies from the bench to bedside.
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Affiliation(s)
- Ralf Watzlawick
- From Charité-Universitätsmedizin Berlin (R.W., M.A.K., J.R., U.D., J.M.S.), corporate member of the Freie Universität Berlin, Humboldt-Universität zu Berlin, and Berlin Institute of Health; Department of Neurology and Experimental Neurology (R.W., M.A.K., J.R., J.M.S.), Charité Campus Mitte, Clinical and Experimental Spinal Cord Injury Research Laboratory (Neuroparaplegiology), Charité-Universitätsmedizin Berlin; Department of Neurosurgery (R.W.), Freiburg University Medical Center, Germany; Department of Neuroscience (A.A.), Central Clinical School, Monash University, Melbourne; Stroke Division (E.S.S., M.M., D.W.H.), Melbourne, Victoria, Australia; Departments of Neurology and Clinical Neurosciences (E.S.S., M.M.), University of Edinburgh, UK; Center for Stroke Research Berlin (U.D.) and Excellence Cluster Neurocure (U.D.), Charité-Universitätsmedizin, Berlin, Germany; German Center for Neurodegenerative Diseases (U.D.), Bonn; Berlin Institute of Health (M.A.K., U.D.), Germany; University of Tasmania (D.W.H.), School of Medicine, Faculty of Health, Medical Sciences Precinct, Hobart, Australia; Department of Neurology (J.M.S.), Spinal Cord Injury Medicine (Paraplegiology), and Belford Center for Spinal Cord Injury (J.M.S.), Departments of Neuroscience and Physical Medicine and Rehabilitation, The Neurological Institute, The Ohio State University, Wexner Medical Center, Columbus
| | - Ana Antonic
- From Charité-Universitätsmedizin Berlin (R.W., M.A.K., J.R., U.D., J.M.S.), corporate member of the Freie Universität Berlin, Humboldt-Universität zu Berlin, and Berlin Institute of Health; Department of Neurology and Experimental Neurology (R.W., M.A.K., J.R., J.M.S.), Charité Campus Mitte, Clinical and Experimental Spinal Cord Injury Research Laboratory (Neuroparaplegiology), Charité-Universitätsmedizin Berlin; Department of Neurosurgery (R.W.), Freiburg University Medical Center, Germany; Department of Neuroscience (A.A.), Central Clinical School, Monash University, Melbourne; Stroke Division (E.S.S., M.M., D.W.H.), Melbourne, Victoria, Australia; Departments of Neurology and Clinical Neurosciences (E.S.S., M.M.), University of Edinburgh, UK; Center for Stroke Research Berlin (U.D.) and Excellence Cluster Neurocure (U.D.), Charité-Universitätsmedizin, Berlin, Germany; German Center for Neurodegenerative Diseases (U.D.), Bonn; Berlin Institute of Health (M.A.K., U.D.), Germany; University of Tasmania (D.W.H.), School of Medicine, Faculty of Health, Medical Sciences Precinct, Hobart, Australia; Department of Neurology (J.M.S.), Spinal Cord Injury Medicine (Paraplegiology), and Belford Center for Spinal Cord Injury (J.M.S.), Departments of Neuroscience and Physical Medicine and Rehabilitation, The Neurological Institute, The Ohio State University, Wexner Medical Center, Columbus
| | - Emily S Sena
- From Charité-Universitätsmedizin Berlin (R.W., M.A.K., J.R., U.D., J.M.S.), corporate member of the Freie Universität Berlin, Humboldt-Universität zu Berlin, and Berlin Institute of Health; Department of Neurology and Experimental Neurology (R.W., M.A.K., J.R., J.M.S.), Charité Campus Mitte, Clinical and Experimental Spinal Cord Injury Research Laboratory (Neuroparaplegiology), Charité-Universitätsmedizin Berlin; Department of Neurosurgery (R.W.), Freiburg University Medical Center, Germany; Department of Neuroscience (A.A.), Central Clinical School, Monash University, Melbourne; Stroke Division (E.S.S., M.M., D.W.H.), Melbourne, Victoria, Australia; Departments of Neurology and Clinical Neurosciences (E.S.S., M.M.), University of Edinburgh, UK; Center for Stroke Research Berlin (U.D.) and Excellence Cluster Neurocure (U.D.), Charité-Universitätsmedizin, Berlin, Germany; German Center for Neurodegenerative Diseases (U.D.), Bonn; Berlin Institute of Health (M.A.K., U.D.), Germany; University of Tasmania (D.W.H.), School of Medicine, Faculty of Health, Medical Sciences Precinct, Hobart, Australia; Department of Neurology (J.M.S.), Spinal Cord Injury Medicine (Paraplegiology), and Belford Center for Spinal Cord Injury (J.M.S.), Departments of Neuroscience and Physical Medicine and Rehabilitation, The Neurological Institute, The Ohio State University, Wexner Medical Center, Columbus
| | - Marcel A Kopp
- From Charité-Universitätsmedizin Berlin (R.W., M.A.K., J.R., U.D., J.M.S.), corporate member of the Freie Universität Berlin, Humboldt-Universität zu Berlin, and Berlin Institute of Health; Department of Neurology and Experimental Neurology (R.W., M.A.K., J.R., J.M.S.), Charité Campus Mitte, Clinical and Experimental Spinal Cord Injury Research Laboratory (Neuroparaplegiology), Charité-Universitätsmedizin Berlin; Department of Neurosurgery (R.W.), Freiburg University Medical Center, Germany; Department of Neuroscience (A.A.), Central Clinical School, Monash University, Melbourne; Stroke Division (E.S.S., M.M., D.W.H.), Melbourne, Victoria, Australia; Departments of Neurology and Clinical Neurosciences (E.S.S., M.M.), University of Edinburgh, UK; Center for Stroke Research Berlin (U.D.) and Excellence Cluster Neurocure (U.D.), Charité-Universitätsmedizin, Berlin, Germany; German Center for Neurodegenerative Diseases (U.D.), Bonn; Berlin Institute of Health (M.A.K., U.D.), Germany; University of Tasmania (D.W.H.), School of Medicine, Faculty of Health, Medical Sciences Precinct, Hobart, Australia; Department of Neurology (J.M.S.), Spinal Cord Injury Medicine (Paraplegiology), and Belford Center for Spinal Cord Injury (J.M.S.), Departments of Neuroscience and Physical Medicine and Rehabilitation, The Neurological Institute, The Ohio State University, Wexner Medical Center, Columbus
| | - Julian Rind
- From Charité-Universitätsmedizin Berlin (R.W., M.A.K., J.R., U.D., J.M.S.), corporate member of the Freie Universität Berlin, Humboldt-Universität zu Berlin, and Berlin Institute of Health; Department of Neurology and Experimental Neurology (R.W., M.A.K., J.R., J.M.S.), Charité Campus Mitte, Clinical and Experimental Spinal Cord Injury Research Laboratory (Neuroparaplegiology), Charité-Universitätsmedizin Berlin; Department of Neurosurgery (R.W.), Freiburg University Medical Center, Germany; Department of Neuroscience (A.A.), Central Clinical School, Monash University, Melbourne; Stroke Division (E.S.S., M.M., D.W.H.), Melbourne, Victoria, Australia; Departments of Neurology and Clinical Neurosciences (E.S.S., M.M.), University of Edinburgh, UK; Center for Stroke Research Berlin (U.D.) and Excellence Cluster Neurocure (U.D.), Charité-Universitätsmedizin, Berlin, Germany; German Center for Neurodegenerative Diseases (U.D.), Bonn; Berlin Institute of Health (M.A.K., U.D.), Germany; University of Tasmania (D.W.H.), School of Medicine, Faculty of Health, Medical Sciences Precinct, Hobart, Australia; Department of Neurology (J.M.S.), Spinal Cord Injury Medicine (Paraplegiology), and Belford Center for Spinal Cord Injury (J.M.S.), Departments of Neuroscience and Physical Medicine and Rehabilitation, The Neurological Institute, The Ohio State University, Wexner Medical Center, Columbus
| | - Ulrich Dirnagl
- From Charité-Universitätsmedizin Berlin (R.W., M.A.K., J.R., U.D., J.M.S.), corporate member of the Freie Universität Berlin, Humboldt-Universität zu Berlin, and Berlin Institute of Health; Department of Neurology and Experimental Neurology (R.W., M.A.K., J.R., J.M.S.), Charité Campus Mitte, Clinical and Experimental Spinal Cord Injury Research Laboratory (Neuroparaplegiology), Charité-Universitätsmedizin Berlin; Department of Neurosurgery (R.W.), Freiburg University Medical Center, Germany; Department of Neuroscience (A.A.), Central Clinical School, Monash University, Melbourne; Stroke Division (E.S.S., M.M., D.W.H.), Melbourne, Victoria, Australia; Departments of Neurology and Clinical Neurosciences (E.S.S., M.M.), University of Edinburgh, UK; Center for Stroke Research Berlin (U.D.) and Excellence Cluster Neurocure (U.D.), Charité-Universitätsmedizin, Berlin, Germany; German Center for Neurodegenerative Diseases (U.D.), Bonn; Berlin Institute of Health (M.A.K., U.D.), Germany; University of Tasmania (D.W.H.), School of Medicine, Faculty of Health, Medical Sciences Precinct, Hobart, Australia; Department of Neurology (J.M.S.), Spinal Cord Injury Medicine (Paraplegiology), and Belford Center for Spinal Cord Injury (J.M.S.), Departments of Neuroscience and Physical Medicine and Rehabilitation, The Neurological Institute, The Ohio State University, Wexner Medical Center, Columbus
| | - Malcolm Macleod
- From Charité-Universitätsmedizin Berlin (R.W., M.A.K., J.R., U.D., J.M.S.), corporate member of the Freie Universität Berlin, Humboldt-Universität zu Berlin, and Berlin Institute of Health; Department of Neurology and Experimental Neurology (R.W., M.A.K., J.R., J.M.S.), Charité Campus Mitte, Clinical and Experimental Spinal Cord Injury Research Laboratory (Neuroparaplegiology), Charité-Universitätsmedizin Berlin; Department of Neurosurgery (R.W.), Freiburg University Medical Center, Germany; Department of Neuroscience (A.A.), Central Clinical School, Monash University, Melbourne; Stroke Division (E.S.S., M.M., D.W.H.), Melbourne, Victoria, Australia; Departments of Neurology and Clinical Neurosciences (E.S.S., M.M.), University of Edinburgh, UK; Center for Stroke Research Berlin (U.D.) and Excellence Cluster Neurocure (U.D.), Charité-Universitätsmedizin, Berlin, Germany; German Center for Neurodegenerative Diseases (U.D.), Bonn; Berlin Institute of Health (M.A.K., U.D.), Germany; University of Tasmania (D.W.H.), School of Medicine, Faculty of Health, Medical Sciences Precinct, Hobart, Australia; Department of Neurology (J.M.S.), Spinal Cord Injury Medicine (Paraplegiology), and Belford Center for Spinal Cord Injury (J.M.S.), Departments of Neuroscience and Physical Medicine and Rehabilitation, The Neurological Institute, The Ohio State University, Wexner Medical Center, Columbus
| | - David W Howells
- From Charité-Universitätsmedizin Berlin (R.W., M.A.K., J.R., U.D., J.M.S.), corporate member of the Freie Universität Berlin, Humboldt-Universität zu Berlin, and Berlin Institute of Health; Department of Neurology and Experimental Neurology (R.W., M.A.K., J.R., J.M.S.), Charité Campus Mitte, Clinical and Experimental Spinal Cord Injury Research Laboratory (Neuroparaplegiology), Charité-Universitätsmedizin Berlin; Department of Neurosurgery (R.W.), Freiburg University Medical Center, Germany; Department of Neuroscience (A.A.), Central Clinical School, Monash University, Melbourne; Stroke Division (E.S.S., M.M., D.W.H.), Melbourne, Victoria, Australia; Departments of Neurology and Clinical Neurosciences (E.S.S., M.M.), University of Edinburgh, UK; Center for Stroke Research Berlin (U.D.) and Excellence Cluster Neurocure (U.D.), Charité-Universitätsmedizin, Berlin, Germany; German Center for Neurodegenerative Diseases (U.D.), Bonn; Berlin Institute of Health (M.A.K., U.D.), Germany; University of Tasmania (D.W.H.), School of Medicine, Faculty of Health, Medical Sciences Precinct, Hobart, Australia; Department of Neurology (J.M.S.), Spinal Cord Injury Medicine (Paraplegiology), and Belford Center for Spinal Cord Injury (J.M.S.), Departments of Neuroscience and Physical Medicine and Rehabilitation, The Neurological Institute, The Ohio State University, Wexner Medical Center, Columbus
| | - Jan M Schwab
- From Charité-Universitätsmedizin Berlin (R.W., M.A.K., J.R., U.D., J.M.S.), corporate member of the Freie Universität Berlin, Humboldt-Universität zu Berlin, and Berlin Institute of Health; Department of Neurology and Experimental Neurology (R.W., M.A.K., J.R., J.M.S.), Charité Campus Mitte, Clinical and Experimental Spinal Cord Injury Research Laboratory (Neuroparaplegiology), Charité-Universitätsmedizin Berlin; Department of Neurosurgery (R.W.), Freiburg University Medical Center, Germany; Department of Neuroscience (A.A.), Central Clinical School, Monash University, Melbourne; Stroke Division (E.S.S., M.M., D.W.H.), Melbourne, Victoria, Australia; Departments of Neurology and Clinical Neurosciences (E.S.S., M.M.), University of Edinburgh, UK; Center for Stroke Research Berlin (U.D.) and Excellence Cluster Neurocure (U.D.), Charité-Universitätsmedizin, Berlin, Germany; German Center for Neurodegenerative Diseases (U.D.), Bonn; Berlin Institute of Health (M.A.K., U.D.), Germany; University of Tasmania (D.W.H.), School of Medicine, Faculty of Health, Medical Sciences Precinct, Hobart, Australia; Department of Neurology (J.M.S.), Spinal Cord Injury Medicine (Paraplegiology), and Belford Center for Spinal Cord Injury (J.M.S.), Departments of Neuroscience and Physical Medicine and Rehabilitation, The Neurological Institute, The Ohio State University, Wexner Medical Center, Columbus.
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Mattucci S, Speidel J, Liu J, Ramer MS, Kwon BK, Tetzlaff W, Oxland TR. Development of a traumatic cervical dislocation spinal cord injury model with residual compression in the rat. J Neurosci Methods 2019; 322:58-70. [PMID: 30951755 DOI: 10.1016/j.jneumeth.2019.03.010] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/20/2018] [Revised: 03/12/2019] [Accepted: 03/15/2019] [Indexed: 12/13/2022]
Abstract
BACKGROUND Preclinical spinal cord injury models do not represent the wide range of biomechanical factors seen in human injuries, such as spinal level, injury mechanism, velocity of spinal cord impact, and residual compression. These factors may be responsible for differences observed between experimental and clinical study results, especially related to the controversial issue of timing of surgical decompression. NEW METHOD Somatosensory Evoked Potentials were used to: a) characterize residual compression depths in a dislocation model, and b) evaluate the physiological effect of whether or not the spinal cord was decompressed following the initial injury, prior to the application of residual compression. Modifications to vertebral clamps and the development of a novel surgical frame allowed us to conduct surgical and injury procedures in a controlled manner without the risk of additional damage to the spinal cord. Behavioural outcomes were evaluated following varying dislocation displacements, in addition to the survivability of 4 h of residual compression following a traumatic injury. RESULTS Residual compression immediately following the initial dislocation demonstrated significantly different electrophysiological response compared to when the residual compression was delayed. COMPARISON WITH EXISTING METHOD There are currently no other residual compression models that utilize a dislocation injury mechanism. Many residual compression studies have demonstrated the effectiveness of early decompression, however the compression of the spinal cord is often not representative of clinical traumatic injuries. Preclinical studies typically model residual compression using a sustained force through quasi-static application, when human injuries often occur at high velocities, followed by a sustained displacement occlusion of the spinal canal. CONCLUSIONS This study has validated several novel procedural approaches and injury parameters, and provided critical details to implement in the development of a traumatic cervical dislocation SCI model with residual compression.
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Affiliation(s)
- Stephen Mattucci
- Orthopaedic and Injury Biomechanics Group, Departments of Orthopaedics and Mechanical Engineering, International Collaboration on Repair Discoveries, University of British Columbia, 818 West 10th Avenue, Vancouver, BC, V5Z 1M9, Canada.
| | - Jason Speidel
- Orthopaedic and Injury Biomechanics Group, Departments of Orthopaedics and Mechanical Engineering, International Collaboration on Repair Discoveries, University of British Columbia, 818 West 10th Avenue, Vancouver, BC, V5Z 1M9, Canada.
| | - Jie Liu
- International Collaboration on Repair Discoveries, University of British Columbia, 818 West 10th Avenue, Vancouver, BC, V5Z 1M9, Canada.
| | - Matt S Ramer
- International Collaboration on Repair Discoveries, University of British Columbia, 818 West 10th Avenue, Vancouver, BC, V5Z 1M9, Canada.
| | - Brian K Kwon
- International Collaboration on Repair Discoveries, University of British Columbia, 818 West 10th Avenue, Vancouver, BC, V5Z 1M9, Canada.
| | - Wolfram Tetzlaff
- International Collaboration on Repair Discoveries, University of British Columbia, 818 West 10th Avenue, Vancouver, BC, V5Z 1M9, Canada.
| | - Thomas R Oxland
- Orthopaedic and Injury Biomechanics Group, Departments of Orthopaedics and Mechanical Engineering, International Collaboration on Repair Discoveries, University of British Columbia, 818 West 10th Avenue, Vancouver, BC, V5Z 1M9, Canada.
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Mattucci S, Speidel J, Liu J, Kwon BK, Tetzlaff W, Oxland TR. Basic biomechanics of spinal cord injury - How injuries happen in people and how animal models have informed our understanding. Clin Biomech (Bristol, Avon) 2019; 64:58-68. [PMID: 29685426 DOI: 10.1016/j.clinbiomech.2018.03.020] [Citation(s) in RCA: 25] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/18/2017] [Revised: 02/05/2018] [Accepted: 03/24/2018] [Indexed: 02/07/2023]
Abstract
The wide variability, or heterogeneity, in human spinal cord injury is due partially to biomechanical factors. This review summarizes our current knowledge surrounding the patterns of human spinal column injury and the biomechanical factors affecting injury. The biomechanics of human spinal injury is studied most frequently with human cadaveric models and the features of the two most common injury patterns, burst fracture and fracture dislocation, are outlined. The biology of spinal cord injury is typically studied with animal models and the effects of the most relevant biomechanical factors - injury mechanism, injury velocity, and residual compression, are described. Tissue damage patterns and behavioural outcomes following dislocation or distraction injury mechanisms differ from the more commonly used contusion mechanism. The velocity of injury affects spinal cord damage, principally in the white matter. Ongoing, or residual compression after the initial impact does affect spinal cord damage, but few models exist that replicate the clinical scenario. Future research should focus on the effects of these biomechanical factors in different preclinical animal models as recent data suggests that treatment outcomes may vary between models.
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Affiliation(s)
- Stephen Mattucci
- International Collaboration on Repair Discoveries (ICORD), University of British Columbia, 818 West 10th Avenue, Vancouver, BC V5Z 1M9, Canada; Department of Mechanical Engineering, University of British Columbia, 6250 Applied Science Lane, Vancouver, BC V6T 1Z4, Canada
| | - Jason Speidel
- International Collaboration on Repair Discoveries (ICORD), University of British Columbia, 818 West 10th Avenue, Vancouver, BC V5Z 1M9, Canada; Department of Mechanical Engineering, University of British Columbia, 6250 Applied Science Lane, Vancouver, BC V6T 1Z4, Canada
| | - Jie Liu
- International Collaboration on Repair Discoveries (ICORD), University of British Columbia, 818 West 10th Avenue, Vancouver, BC V5Z 1M9, Canada
| | - Brian K Kwon
- International Collaboration on Repair Discoveries (ICORD), University of British Columbia, 818 West 10th Avenue, Vancouver, BC V5Z 1M9, Canada; Department of Orthopaedics, University of British Columbia, 910 West 10th Avenue, Vancouver, BC V5Z 1M9, Canada
| | - Wolfram Tetzlaff
- International Collaboration on Repair Discoveries (ICORD), University of British Columbia, 818 West 10th Avenue, Vancouver, BC V5Z 1M9, Canada; Departments of Zoology and Surgery, University of British Columbia, 6270 University Boulevard, Vancouver, BC V6T 1Z4, Canada
| | - Thomas R Oxland
- International Collaboration on Repair Discoveries (ICORD), University of British Columbia, 818 West 10th Avenue, Vancouver, BC V5Z 1M9, Canada; Department of Mechanical Engineering, University of British Columbia, 6250 Applied Science Lane, Vancouver, BC V6T 1Z4, Canada; Department of Orthopaedics, University of British Columbia, 910 West 10th Avenue, Vancouver, BC V5Z 1M9, Canada.
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9
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Gadomski BC, Shetye SS, Hindman BJ, Dexter F, Santoni BG, Todd MM, Traynelis VC, From RP, Fontes RB, Puttlitz CM. Intubation biomechanics: validation of a finite element model of cervical spine motion during endotracheal intubation in intact and injured conditions. J Neurosurg Spine 2018; 28:10-22. [DOI: 10.3171/2017.5.spine17189] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
OBJECTIVEBecause of limitations inherent to cadaver models of endotracheal intubation, the authors’ group developed a finite element (FE) model of the human cervical spine and spinal cord. Their aims were to 1) compare FE model predictions of intervertebral motion during intubation with intervertebral motion measured in patients with intact cervical spines and in cadavers with spine injuries at C-2 and C3–4 and 2) estimate spinal cord strains during intubation under these conditions.METHODSThe FE model was designed to replicate the properties of an intact (stable) spine in patients, C-2 injury (Type II odontoid fracture), and a severe C3–4 distractive-flexion injury from prior cadaver studies. The authors recorded the laryngoscope force values from 2 different laryngoscopes (Macintosh, high intubation force; Airtraq, low intubation force) used during the patient and cadaver intubation studies. FE-modeled motion was compared with experimentally measured motion, and corresponding cord strain values were calculated.RESULTSFE model predictions of intact intervertebral motions were comparable to motions measured in patients and in cadavers at occiput–C2. In intact subaxial segments, the FE model more closely predicted patient intervertebral motions than did cadavers. With C-2 injury, FE-predicted motions did not differ from cadaver measurements. With C3–4 injury, however, the FE model predicted greater motions than were measured in cadavers. FE model cord strains during intubation were greater for the Macintosh laryngoscope than the Airtraq laryngoscope but were comparable among the 3 conditions (intact, C-2 injury, and C3–4 injury).CONCLUSIONSThe FE model is comparable to patients and cadaver models in estimating occiput–C2 motion during intubation in both intact and injured conditions. The FE model may be superior to cadavers in predicting motions of subaxial segments in intact and injured conditions.
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Affiliation(s)
- Benjamin C. Gadomski
- 1Department of Mechanical Engineering, School of Biomedical Engineering, Orthopaedic Bioengineering Research Laboratory, Colorado State University, Fort Collins, Colorado
| | - Snehal S. Shetye
- 1Department of Mechanical Engineering, School of Biomedical Engineering, Orthopaedic Bioengineering Research Laboratory, Colorado State University, Fort Collins, Colorado
| | - Bradley J. Hindman
- 2Department of Anesthesia, University of Iowa Roy J. and Lucille A. Carver College of Medicine, Iowa City, Iowa
| | - Franklin Dexter
- 2Department of Anesthesia, University of Iowa Roy J. and Lucille A. Carver College of Medicine, Iowa City, Iowa
| | | | - Michael M. Todd
- 4Department of Anesthesia, University of Minnesota, Minneapolis, Minnesota; and
| | | | - Robert P. From
- 2Department of Anesthesia, University of Iowa Roy J. and Lucille A. Carver College of Medicine, Iowa City, Iowa
| | - Ricardo B. Fontes
- 5Department of Neurosurgery, Rush University Medical Center, Chicago, Illinois
| | - Christian M. Puttlitz
- 1Department of Mechanical Engineering, School of Biomedical Engineering, Orthopaedic Bioengineering Research Laboratory, Colorado State University, Fort Collins, Colorado
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Orr MB, Simkin J, Bailey WM, Kadambi NS, McVicar AL, Veldhorst AK, Gensel JC. Compression Decreases Anatomical and Functional Recovery and Alters Inflammation after Contusive Spinal Cord Injury. J Neurotrauma 2017; 34:2342-2352. [PMID: 28381129 DOI: 10.1089/neu.2016.4915] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
Experimental models of spinal cord injury (SCI) typically utilize contusion or compression injuries. Clinically, however, SCI is heterogeneous and the primary injury mode may affect secondary injury progression and neuroprotective therapeutic efficacy. Specifically, immunomodulatory agents are of therapeutic interest because the activation state of SCI macrophages may facilitate pathology but also improve repair. It is unknown currently how the primary injury biomechanics affect macrophage activation. Therefore, to determine the effects of compression subsequent to spinal contusion, we examined recovery, secondary injury, and macrophage activation in C57/BL6 mice after SCI with or without a 20 sec compression at two contusion impact forces (50 and 75 kdyn). We observed that regardless of the initial impact force, compression increased tissue damage and worsened functional recovery. Interestingly, compression-dependent damage is not evident until one week after SCI. Further, compression limits functional recovery to the first two weeks post-SCI; in the absence of compression, mice receiving contusion SCI recover for four weeks. To determine whether the recovery plateau is indicative of compression-specific inflammatory responses, we examined macrophage activation with immunohistochemical markers of purportedly pathological (CD86 and macrophage receptor with collagenous structure [MARCO]) and reparative macrophages (arginase [Arg1] and CD206). We detected significant increases in macrophages expression of MARCO and decreases in macrophage Arg1 expression with compression, suggesting a biomechanical-dependent shift in SCI macrophage activation. Collectively, compression-induced alterations in tissue and functional recovery and inflammation highlight the need to consider the primary SCI biomechanics in the design and clinical implementation of immunomodulatory therapies.
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Affiliation(s)
- Michael B Orr
- 1 Spinal Cord and Brain Injury Research Center and the Department of Physiology, the University of Kentucky , Lexington, Kentucky
- 3 Integrated Biomedical Sciences Graduate Program, the University of Kentucky , Lexington, Kentucky
| | - Jennifer Simkin
- 1 Spinal Cord and Brain Injury Research Center and the Department of Physiology, the University of Kentucky , Lexington, Kentucky
- 2 Department of Biology, the University of Kentucky , Lexington, Kentucky
| | - William M Bailey
- 1 Spinal Cord and Brain Injury Research Center and the Department of Physiology, the University of Kentucky , Lexington, Kentucky
| | - Neha S Kadambi
- 4 Math, Science, and Technology Center Program, Dunbar High School , Lexington, Kentucky
| | - Anna Leigh McVicar
- 1 Spinal Cord and Brain Injury Research Center and the Department of Physiology, the University of Kentucky , Lexington, Kentucky
| | - Amy K Veldhorst
- 1 Spinal Cord and Brain Injury Research Center and the Department of Physiology, the University of Kentucky , Lexington, Kentucky
| | - John C Gensel
- 1 Spinal Cord and Brain Injury Research Center and the Department of Physiology, the University of Kentucky , Lexington, Kentucky
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11
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Orr MB, Gensel JC. Interactions of primary insult biomechanics and secondary cascades in spinal cord injury: implications for therapy. Neural Regen Res 2017; 12:1618-1619. [PMID: 29171424 PMCID: PMC5696840 DOI: 10.4103/1673-5374.217332] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Affiliation(s)
- Michael B Orr
- Spinal Cord and Brain Injury Research Center and the Department of Physiology, the University of Kentucky, Lexington, KY; Integrated Biomedical Sciences Graduate Program, the University of Kentucky, Lexington, KY, USA
| | - John C Gensel
- Spinal Cord and Brain Injury Research Center and the Department of Physiology, the University of Kentucky, Lexington, KY, USA
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12
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Bhatnagar T, Liu J, Yung A, Cripton P, Kozlowski P, Tetzlaff W, Oxland T. Relating Histopathology and Mechanical Strain in Experimental Contusion Spinal Cord Injury in a Rat Model. J Neurotrauma 2016; 33:1685-95. [PMID: 26729511 PMCID: PMC5035832 DOI: 10.1089/neu.2015.4200] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022] Open
Abstract
During traumatic spinal cord injury (SCI), the spinal cord is subject to external displacements that result in damage of neural tissues. These displacements produce complex internal deformations, or strains, of the spinal cord parenchyma. The aim of this study is to determine a relationship between these internal strains during SCI and primary damage to spinal cord gray matter (GM) in an in vivo rat contusion model. Using magnetic resonance imaging and novel image registration methods, we measured three-dimensional (3D) mechanical strain in in vivo rat cervical spinal cord (n = 12) during an imposed contusion injury. We then assessed expression of the neuronal transcription factor, neuronal nuclei (NeuN), in ventral horns of GM (at the epicenter of injury as well as at intervals cranially and caudally), immediately post-injury. We found that minimum principal strain was most strongly correlated with loss of NeuN stain across all animals (R2 = 0.19), but varied in strength between individual animals (R2 = 0.06–0.52). Craniocaudal distribution of anatomical damage was similar to measured strain distribution. A Monte Carlo simulation was used to assess strain field error, and minimum principal strain (which ranged from 8% to 36% in GM ventral horns) exhibited a standard deviation of 2.6% attributed to the simulated error. This study is the first to measure 3D deformation of the spinal cord and relate it to patterns of ensuing tissue damage in an in vivo model. It provides a platform on which to build future studies addressing the tolerance of spinal cord tissue to mechanical deformation.
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Affiliation(s)
- Tim Bhatnagar
- 1 International Collaboration On Repair Discoveries (ICORD), University of British Columbia, Vancouver , British Columbia, Canada .,2 Department of Mechanical Engineering, University of British Columbia , Vancouver, British Columbia, Canada
| | - Jie Liu
- 1 International Collaboration On Repair Discoveries (ICORD), University of British Columbia, Vancouver , British Columbia, Canada
| | - Andrew Yung
- 1 International Collaboration On Repair Discoveries (ICORD), University of British Columbia, Vancouver , British Columbia, Canada .,3 UBC MRI Research Center, University of British Columbia , Vancouver, British Columbia, Canada
| | - Peter Cripton
- 1 International Collaboration On Repair Discoveries (ICORD), University of British Columbia, Vancouver , British Columbia, Canada .,2 Department of Mechanical Engineering, University of British Columbia , Vancouver, British Columbia, Canada
| | - Piotr Kozlowski
- 1 International Collaboration On Repair Discoveries (ICORD), University of British Columbia, Vancouver , British Columbia, Canada .,3 UBC MRI Research Center, University of British Columbia , Vancouver, British Columbia, Canada
| | - Wolfram Tetzlaff
- 1 International Collaboration On Repair Discoveries (ICORD), University of British Columbia, Vancouver , British Columbia, Canada .,4 Department of Zoology, University of British Columbia , Vancouver, British Columbia, Canada
| | - Thomas Oxland
- 1 International Collaboration On Repair Discoveries (ICORD), University of British Columbia, Vancouver , British Columbia, Canada .,2 Department of Mechanical Engineering, University of British Columbia , Vancouver, British Columbia, Canada .,5 Department of Orthopedics, University of British Columbia , Vancouver, British Columbia, Canada
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13
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Longitudinal extension of myelomalacia by intramedullary and subdural hemorrhage in a canine model of spinal cord injury. Spine J 2016; 16:82-90. [PMID: 26386168 DOI: 10.1016/j.spinee.2015.09.018] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/05/2015] [Revised: 08/12/2015] [Accepted: 09/03/2015] [Indexed: 02/03/2023]
Abstract
BACKGROUND CONTEXT In canine intervertebral disc (IVD) extrusion, a spontaneous animal model of spinal cord injury, hemorrhage is a consistent finding. In rodent models, hemorrhage might be involved in secondary tissue destruction by biochemical mechanisms. PURPOSE This study aimed to investigate a causal association between the extents of intramedullary, subdural and epidural hemorrhage and the severity of spinal cord damage following IVD extrusion in dogs. STUDY DESIGN/SETTING A retrospective study using histologic spinal cord sections from 83 dogs euthanized following IVD extrusion was carried out. METHODS The degree of hemorrhage (intramedullary, subdural, epidural), the degree of spinal cord damage in the epicenter (white and gray matter), and the longitudinal extent of myelomalacia were graded. Associations between the extent of hemorrhage and the degree of spinal cord damage were evaluated statistically. RESULTS Intramedullary and subdural hemorrhages were significantly associated with the degree of white (p<.001/ p=.004) and gray (both p<.001) matter damage, and with the longitudinal extension of myelomalacia (p<.001/p=.005). Intriguingly, accumulation of hemorrhagic cord debris inside or dorsal to a distended and ruptured central canal in segments distant to the epicenter of the lesion was observed exhibiting a wave-like pattern on longitudinal assessment. The occurrence of this debris accumulation was associated with high degrees of tissue destruction (all p<.001). CONCLUSIONS Tissue liquefaction and increased intramedullary pressure associated with hemorrhage are involved in the progression of spinal cord destruction in a canine model of spinal cord injury and ascending or descending myelomalacia. Functional and dynamic studies are needed to investigate this concept further.
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Ramer LM, Ramer MS, Bradbury EJ. Restoring function after spinal cord injury: towards clinical translation of experimental strategies. Lancet Neurol 2014; 13:1241-56. [PMID: 25453463 DOI: 10.1016/s1474-4422(14)70144-9] [Citation(s) in RCA: 195] [Impact Index Per Article: 19.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
Abstract
Spinal cord injury is currently incurable and treatment is limited to minimising secondary complications and maximising residual function by rehabilitation. Improved understanding of the pathophysiology of spinal cord injury and the factors that prevent nerve and tissue repair has fuelled a move towards more ambitious experimental treatments aimed at promoting neuroprotection, axonal regeneration, and neuroplasticity. By necessity, these new options are more invasive. However, in view of recent advances in spinal cord injury research and demand from patients, clinicians, and the scientific community to push promising experimental treatments to the clinic, momentum and optimism exist for the translation of candidate experimental treatments to clinical spinal cord injury. The ability to rescue, reactivate, and rewire spinal systems to restore function after spinal cord injury might soon be within reach.
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Affiliation(s)
- Leanne M Ramer
- King's College London, Regeneration Group, Wolfson Centre for Age-Related Diseases, Guy's Campus, London, UK; International Collaboration On Repair Discoveries, Blusson Spinal Cord Centre, Vancouver General Hospital, Vancouver, BC, Canada
| | - Matt S Ramer
- King's College London, Regeneration Group, Wolfson Centre for Age-Related Diseases, Guy's Campus, London, UK; International Collaboration On Repair Discoveries, Blusson Spinal Cord Centre, Vancouver General Hospital, Vancouver, BC, Canada; Department of Zoology, University of British Columbia, Vancouver, BC, Canada
| | - Elizabeth J Bradbury
- King's College London, Regeneration Group, Wolfson Centre for Age-Related Diseases, Guy's Campus, London, UK.
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