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Claeson AA, Vresilovic EJ, Showalter BL, Wright AC, Gee JC, Malhotra NR, Elliott DM. Human Disc Nucleotomy Alters Annulus Fibrosus Mechanics at Both Reference and Compressed Loads. J Biomech Eng 2019; 141:1110011-11100112. [PMID: 31141601 PMCID: PMC6808005 DOI: 10.1115/1.4043874] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2018] [Revised: 05/25/2019] [Indexed: 10/19/2023]
Abstract
Nucleotomy is a common surgical procedure and is also performed in ex vivo mechanical testing to model decreased nucleus pulposus (NP) pressurization that occurs with degeneration. Here, we implement novel and noninvasive methods using magnetic resonance imaging (MRI) to study internal 3D annulus fibrosus (AF) deformations after partial nucleotomy and during axial compression by evaluating changes in internal AF deformation at reference loads (50 N) and physiological compressive loads (∼10% strain). One particular advantage of this methodology is that the full 3D disc deformation state, inclusive of both in-plane and out-of-plane deformations, can be quantified through the use of a high-resolution volumetric MR scan sequence and advanced image registration. Intact grade II L3-L4 cadaveric human discs before and after nucleotomy were subjected to identical mechanical testing and imaging protocols. Internal disc deformation fields were calculated by registering MR images captured in each loading state (reference and compressed) and each condition (intact and nucleotomy). Comparisons were drawn between the resulting three deformation states (intact at compressed load, nucleotomy at reference load, nucleotomy at compressed load) with regard to the magnitude of internal strain and direction of internal displacements. Under compressed load, internal AF axial strains averaged -18.5% when intact and -22.5% after nucleotomy. Deformation orientations were significantly altered by nucleotomy and load magnitude. For example, deformations of intact discs oriented in-plane, whereas deformations after nucleotomy oriented axially. For intact discs, in-plane components of displacements under compressive loads oriented radially outward and circumferentially. After nucleotomy, in-plane displacements were oriented radially inward under reference load and were not significantly different from the intact state at compressed loads. Re-establishment of outward displacements after nucleotomy indicates increased axial loading restores the characteristics of internal pressurization. Results may have implications for the recurrence of pain, design of novel therapeutics, or progression of disc degeneration.
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Affiliation(s)
- Amy A Claeson
- Mem. ASMEBiomedical Engineering,University of Delaware,160 Colburn Lab,150 Academy Street,Newark, DE 19716e-mail:
| | - Edward J Vresilovic
- Orthopaedic and Rehabilitation,Pennsylvania State University,EC089 500 University Drive,Hershey, PA 17033e-mail:
| | - Brent L Showalter
- Bioengineering,University of Pennsylvania,242 Stemmler Hall,36th Street & Hamilton Walk,Philadelphia, PA 19104e-mail:
| | - Alexander C Wright
- Radiology,University of Pennsylvania,1st Floor Silverstein Pavilion,3400 Spruce Street,Philadelphia, PA 19104e-mail:
| | - James C Gee
- Radiology,University of Pennsylvania,6th Floor Richards,3700 Hamilton Walk,Philadelphia, PA 19104e-mail:
| | - Neil R Malhotra
- Neurosurgery,University of Pennsylvania,3rd Floor Silverstein Pavilion,3400 Spruce Street,Philadelphia, PA 19104e-mail:
| | - Dawn M Elliott
- Mem. ASMEBiomedical Engineering,University of Delaware,160 Colburn Lab,150 Academy Street,Newark, DE 19716e-mail:
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Hyperbaric oxygen therapy reduces apoptosis and dendritic/synaptic degeneration via the BDNF/TrkB signaling pathways in SCI rats. Life Sci 2019; 229:187-199. [DOI: 10.1016/j.lfs.2019.05.029] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/19/2019] [Revised: 05/06/2019] [Accepted: 05/10/2019] [Indexed: 12/15/2022]
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Jones CF, Clarke EC. Engineering approaches to understanding mechanisms of spinal column injury leading to spinal cord injury. Clin Biomech (Bristol, Avon) 2019; 64:69-81. [PMID: 29625748 DOI: 10.1016/j.clinbiomech.2018.03.019] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/25/2017] [Revised: 02/16/2018] [Accepted: 03/24/2018] [Indexed: 02/07/2023]
Abstract
BACKGROUND The mechanical interactions occurring between the spinal column and spinal cord during an injury event are complex and variable, and likely have implications for the clinical presentation and prognosis of the individual. METHODS The engineering approaches that have been developed to better understand spinal column and cord interactions during an injury event are discussed. These include injury models utilising human and animal cadaveric specimens, in vivo anaesthetised animals, finite element models, inanimate physical systems and combinations thereof. FINDINGS The paper describes the development of these modelling approaches, discusses the advantages and disadvantages of the various models, and the major outcomes that have had implications for spinal cord injury research and clinical practice. INTERPRETATION The contribution of these four engineering approaches to understanding the interaction between the biomechanics and biology of spinal cord injury is substantial; they have improved our understanding of the factors contributing to the spinal column disruption, the degree of spinal cord deformation or motion, and the resultant neurological deficit and imaging features. Models of the injury event are challenging to produce, but technological advances are likely to improve these models and, consequently, our understanding of the mechanical context in which the biological injury occurs.
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Affiliation(s)
- Claire F Jones
- Spinal Research Group, Centre for Orthopaedics and Trauma Research, Adelaide Medical School, The University of Adelaide, Australia; School of Mechanical Engineering, The University of Adelaide, Australia
| | - Elizabeth C Clarke
- Institute for Bone and Joint Research, Kolling Institute, Sydney Medical School, University of Sydney, Australia.
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Lucas E, Whyte T, Liu J, Russell C, Tetzlaff W, Cripton PA. High-Speed Fluoroscopy to Measure Dynamic Spinal Cord Deformation in an In Vivo Rat Model. J Neurotrauma 2018; 35:2572-2580. [PMID: 29786472 DOI: 10.1089/neu.2017.5478] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023] Open
Abstract
Although spinal cord deformation is thought to be a predictor of injury severity, few researchers have investigated dynamic cord deformation, in vivo, during impact. This is needed to establish correlations among impact parameters, internal cord deformation, and histological and functional outcomes. Relying on surface deformations alone may not sufficiently represent spinal cord deformation. The objective of this study was to develop a high-speed fluoroscopic method of tracking the surface and internal cord deformations of rat spinal cord during experimental cord injury. Two radio-opaque beads were injected into the cord at C5/6 in the dorsal and ventral white matter. Four additional beads were glued to the surface of the cord. Dynamic bead displacement was tracked during a dorsal impact (130 mm/sec, 1 mm depth) by high-speed radiographic imaging at 3000 FPS, laterally. The internal spinal cord beads displaced significantly more than the surface beads in the ventral direction (1.1-1.9 times) and more than most surface beads in the cranial direction (1.2-1.5 times). The dorsal beads (internal and surface) displaced more than the ventral beads during all impacts. The bead displacement pattern implies that the spinal cord undergoes complex internal and surface deformations during impact. Residual displacement of the internal beads was significantly greater than that of the surface beads in the cranial-caudal direction but not the dorsoventral direction. Finite element simulation confirmed that the additional bead mass likely had little effect on the internal cord deformations. These results support the merit of this technique for measuring in vivo spinal cord deformation.
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Affiliation(s)
- Erin Lucas
- 1 Orthopaedic Injury Biomechanics Group, Departments of Mechanical Engineering and Orthopaedics and the School of Biomedical Engineering, The University of British Columbia , Vancouver, British Columbia, Canada .,2 International Collaboration on Repair Discoveries (ICORD), The University of British Columbia , Vancouver, British Columbia, Canada
| | - Thomas Whyte
- 1 Orthopaedic Injury Biomechanics Group, Departments of Mechanical Engineering and Orthopaedics and the School of Biomedical Engineering, The University of British Columbia , Vancouver, British Columbia, Canada .,2 International Collaboration on Repair Discoveries (ICORD), The University of British Columbia , Vancouver, British Columbia, Canada
| | - Jie Liu
- 2 International Collaboration on Repair Discoveries (ICORD), The University of British Columbia , Vancouver, British Columbia, Canada
| | - Colin Russell
- 1 Orthopaedic Injury Biomechanics Group, Departments of Mechanical Engineering and Orthopaedics and the School of Biomedical Engineering, The University of British Columbia , Vancouver, British Columbia, Canada .,2 International Collaboration on Repair Discoveries (ICORD), The University of British Columbia , Vancouver, British Columbia, Canada
| | - Wolfram Tetzlaff
- 2 International Collaboration on Repair Discoveries (ICORD), The University of British Columbia , Vancouver, British Columbia, Canada
| | - Peter Alec Cripton
- 1 Orthopaedic Injury Biomechanics Group, Departments of Mechanical Engineering and Orthopaedics and the School of Biomedical Engineering, The University of British Columbia , Vancouver, British Columbia, Canada .,2 International Collaboration on Repair Discoveries (ICORD), The University of British Columbia , Vancouver, British Columbia, Canada
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Cordaro M, Casili G, Paterniti I, Cuzzocrea S, Esposito E. Fumaric Acid Esters Attenuate Secondary Degeneration after Spinal Cord Injury. J Neurotrauma 2017; 34:3027-3040. [DOI: 10.1089/neu.2016.4678] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022] Open
Affiliation(s)
- Marika Cordaro
- Department of Chemical, Biological, Pharmaceutical and Environmental Sciences, University of Messina, Messina, Italy
| | - Giovanna Casili
- Department of Chemical, Biological, Pharmaceutical and Environmental Sciences, University of Messina, Messina, Italy
| | - Irene Paterniti
- Department of Chemical, Biological, Pharmaceutical and Environmental Sciences, University of Messina, Messina, Italy
| | - Salvatore Cuzzocrea
- Department of Chemical, Biological, Pharmaceutical and Environmental Sciences, University of Messina, Messina, Italy
- Pharmacological and Physiological Science, Saint Louis University School of Medicine, St. Louis, Missouri
| | - Emanuela Esposito
- Department of Chemical, Biological, Pharmaceutical and Environmental Sciences, University of Messina, Messina, Italy
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Chen K, Liu J, Assinck P, Bhatnagar T, Streijger F, Zhu Q, Dvorak MF, Kwon BK, Tetzlaff W, Oxland TR. Differential Histopathological and Behavioral Outcomes Eight Weeks after Rat Spinal Cord Injury by Contusion, Dislocation, and Distraction Mechanisms. J Neurotrauma 2016; 33:1667-84. [PMID: 26671448 PMCID: PMC5035937 DOI: 10.1089/neu.2015.4218] [Citation(s) in RCA: 36] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
The objective of this study was to compare the long-term histological and behavioral outcomes after spinal cord injury (SCI) induced by one of three distinct biomechanical mechanisms: dislocation, contusion, and distraction. Thirty male Sprague-Dawley rats were randomized to incur a traumatic cervical SCI by one of these three clinically relevant mechanisms. The injured cervical spines were surgically stabilized, and motor function was assessed for the following 8 weeks. The spinal cords were then harvested for histologic analysis. Quantification of white matter sparing using Luxol fast blue staining revealed that dislocation injury caused the greatest overall loss of white matter, both laterally and along the rostrocaudal axis of the injured cord. Distraction caused enlarged extracellular spaces and structural alteration in the white matter but spared the most myelinated axons overall. Contusion caused the most severe loss of myelinated axons in the dorsal white matter. Immunohistochemistry for the neuronal marker NeuN combined with Fluoro Nissl revealed that the dislocation mechanism resulted in the greatest neuronal cell losses in both the ventral and dorsal horns. After the distraction injury mechanism, animals displayed no recovery of grip strength over time, in contrast to the animals subjected to contusion or dislocation injuries. After the dislocation injury mechanism, animals displayed no improvement in the grooming test, in contrast to the animals subjected to contusion or distraction injuries. These data indicate that different SCI mechanisms result in distinct patterns of histopathology and behavioral recovery. Understanding this heterogeneity may be important for the future development of therapeutic interventions that target specific neuropathology after SCI.
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Affiliation(s)
- Kinon Chen
- International Collaboration on Repair Discoveries (ICORD), University of British Columbia, Vancouver, British Columbia, Canada
- Department of Orthopaedics, University of British Columbia, Vancouver, British Columbia, Canada
- School of Biological Science and Medical Engineering, Beihang University, Haidian, Beijing, China
| | - Jie Liu
- International Collaboration on Repair Discoveries (ICORD), University of British Columbia, Vancouver, British Columbia, Canada
| | - Peggy Assinck
- International Collaboration on Repair Discoveries (ICORD), University of British Columbia, Vancouver, British Columbia, Canada
- Graduate Program in Neuroscience, University of British Columbia, Vancouver, British Columbia, Canada
| | - Tim Bhatnagar
- International Collaboration on Repair Discoveries (ICORD), University of British Columbia, Vancouver, British Columbia, Canada
- Department of Mechanical Engineering, University of British Columbia, Vancouver, British Columbia, Canada
| | - Femke Streijger
- International Collaboration on Repair Discoveries (ICORD), University of British Columbia, Vancouver, British Columbia, Canada
| | - Qingan Zhu
- International Collaboration on Repair Discoveries (ICORD), University of British Columbia, Vancouver, British Columbia, Canada
- Department of Orthopaedics, University of British Columbia, Vancouver, British Columbia, Canada
| | - Marcel F. Dvorak
- International Collaboration on Repair Discoveries (ICORD), University of British Columbia, Vancouver, British Columbia, Canada
- Department of Orthopaedics, University of British Columbia, Vancouver, British Columbia, Canada
| | - Brian K. Kwon
- International Collaboration on Repair Discoveries (ICORD), University of British Columbia, Vancouver, British Columbia, Canada
- Department of Orthopaedics, University of British Columbia, Vancouver, British Columbia, Canada
| | - Wolfram Tetzlaff
- International Collaboration on Repair Discoveries (ICORD), University of British Columbia, Vancouver, British Columbia, Canada
- Department of Zoology and Surgery, University of British Columbia, Vancouver, British Columbia, Canada
| | - Thomas R. Oxland
- International Collaboration on Repair Discoveries (ICORD), University of British Columbia, Vancouver, British Columbia, Canada
- Department of Mechanical Engineering, University of British Columbia, Vancouver, British Columbia, Canada
- Department of Orthopaedics, University of British Columbia, Vancouver, British Columbia, Canada
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Jannesar S, Nadler B, Sparrey CJ. The Transverse Isotropy of Spinal Cord White Matter Under Dynamic Load. J Biomech Eng 2016; 138:2536524. [DOI: 10.1115/1.4034171] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/04/2016] [Indexed: 01/31/2023]
Abstract
The rostral-caudally aligned fiber-reinforced structure of spinal cord white matter (WM) gives rise to transverse isotropy in the material. Stress and strain patterns generated in the spinal cord parenchyma following spinal cord injury (SCI) are multidirectional and dependent on the mechanism of the injury. Our objective was to develop a WM constitutive model that captures the material transverse isotropy under dynamic loading. The WM mechanical behavior was extracted from the published tensile and compressive experiments. Combinations of isotropic and fiber-reinforcing models were examined in a conditional quasi-linear viscoelastic (QLV) formulation to capture the WM mechanical behavior. The effect of WM transverse isotropy on SCI model outcomes was evaluated by simulating a nonhuman primate (NHP) contusion injury experiment. A second-order reduced polynomial hyperelastic energy potential conditionally combined with a quadratic reinforcing function in a four-term Prony series QLV model best captured the WM mechanical behavior (0.89 < R2 < 0.99). WM isotropic and transversely isotropic material models combined with discrete modeling of the pia mater resulted in peak impact forces that matched the experimental outcomes. The transversely isotropic WM with discrete pia mater resulted in maximum principal strain (MPS) distributions which effectively captured the combination of ipsilateral peripheral WM sparing, ipsilateral injury and contralateral sparing, and the rostral/caudal spread of damage observed in in vivo injuries. The results suggest that the WM transverse isotropy could have an important role in correlating tissue damage with mechanical measures and explaining the directional sensitivity of the spinal cord to injury.
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Affiliation(s)
- Shervin Jannesar
- Department of Mechatronic Systems Engineering, Simon Fraser University, 250-13450 102 Avenue, Surrey, BC V3T 0A3, Canada e-mail:
| | - Ben Nadler
- Department of Mechanical Engineering, University of Victoria, Victoria, BC, Canada e-mail:
| | - Carolyn J. Sparrey
- Department of Mechatronic Systems Engineering, Simon Fraser University, 250-13450 102 Avenue, Surrey, BC V3T 0A3, Canada
- International Collaboration on Repair Discoveries (ICORD), Vancouver, BC V5Z 1M9, Canada e-mail:
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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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