1
|
Sudres P, Evin M, Wagnac E, Bailly N, Diotalevi L, Melot A, Arnoux PJ, Petit Y. Tensile mechanical properties of the cervical, thoracic and lumbar porcine spinal meninges. J Mech Behav Biomed Mater 2021; 115:104280. [PMID: 33395616 DOI: 10.1016/j.jmbbm.2020.104280] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2020] [Revised: 12/03/2020] [Accepted: 12/12/2020] [Indexed: 10/22/2022]
Abstract
BACKGROUND The spinal meninges play a mechanical protective role for the spinal cord. Better knowledge of the mechanical behavior of these tissues wrapping the cord is required to accurately model the stress and strain fields of the spinal cord during physiological or traumatic motions. Then, the mechanical properties of meninges along the spinal canal are not well documented. The aim of this study was to quantify the elastic meningeal mechanical properties along the porcine spinal cord in both the longitudinal direction and in the circumferential directions for the dura-arachnoid maters complex (DAC) and solely in the longitudinal direction for the pia mater. This analysis was completed in providing a range of isotropic hyperelastic coefficients to take into account the toe region. METHODS Six complete spines (C0 - L5) were harvested from pigs (2-3 months) weighing 43±13 kg. The mechanical tests were performed within 12 h post mortem. A preload of 0.5 N was applied to the pia mater and of 2 N to the DAC samples, followed by 30 preconditioning cycles. Specimens were then loaded to failure at the same strain rate 0.2 mm/s (approximately 0.02/s, traction velocity/length of the sample) up to 12 mm of displacement. RESULTS The following mean values were proposed for the elastic moduli of the spinal meninges. Longitudinal DAC elastic moduli: 22.4 MPa in cervical, 38.1 MPa in thoracic and 36.6 MPa in lumbar spinal levels; circumferential DAC elastic moduli: 20.6 MPa in cervical, 21.2 MPa in thoracic and 12.2 MPa in lumbar spinal levels; and longitudinal pia mater elastic moduli: 18.4 MPa in cervical, 17.2 MPa in thoracic and 19.6 MPa in lumbar spinal levels. DISCUSSION The variety of mechanical properties of the spinal meninges suggests that it cannot be regarded as a homogenous structure along the whole length of the spinal cord.
Collapse
Affiliation(s)
- Patrice Sudres
- Laboratoire de Biomécanique Appliquée, UMRT24 AMU/IFSTTAR, Marseille, France; iLab-Spine - Laboratoire International en Imagerie et Biomécanique du Rachis, Marseille, France & Montréal, Canada
| | - Morgane Evin
- Laboratoire de Biomécanique Appliquée, UMRT24 AMU/IFSTTAR, Marseille, France; iLab-Spine - Laboratoire International en Imagerie et Biomécanique du Rachis, Marseille, France & Montréal, Canada.
| | - Eric Wagnac
- Department of Mechanical Engineering, École de Technologie Supérieure, 1100 Notre-Dame Street West, Montréal, Québec H3C 1K3, Canada; Research Center, Hôpital du Sacré-Coeur de Montréal, 5400 Gouin blvd, Montréal Québec, H4J 1C5, Canada; iLab-Spine - Laboratoire International en Imagerie et Biomécanique du Rachis, Marseille, France & Montréal, Canada
| | - Nicolas Bailly
- Department of Mechanical Engineering, École de Technologie Supérieure, 1100 Notre-Dame Street West, Montréal, Québec H3C 1K3, Canada; Research Center, Hôpital du Sacré-Coeur de Montréal, 5400 Gouin blvd, Montréal Québec, H4J 1C5, Canada; iLab-Spine - Laboratoire International en Imagerie et Biomécanique du Rachis, Marseille, France & Montréal, Canada
| | - Lucien Diotalevi
- Department of Mechanical Engineering, École de Technologie Supérieure, 1100 Notre-Dame Street West, Montréal, Québec H3C 1K3, Canada; Research Center, Hôpital du Sacré-Coeur de Montréal, 5400 Gouin blvd, Montréal Québec, H4J 1C5, Canada; iLab-Spine - Laboratoire International en Imagerie et Biomécanique du Rachis, Marseille, France & Montréal, Canada
| | - Anthony Melot
- Laboratoire de Biomécanique Appliquée, UMRT24 AMU/IFSTTAR, Marseille, France; iLab-Spine - Laboratoire International en Imagerie et Biomécanique du Rachis, Marseille, France & Montréal, Canada; Hôpital privé Clairval, Marseille, France
| | - Pierre-Jean Arnoux
- Laboratoire de Biomécanique Appliquée, UMRT24 AMU/IFSTTAR, Marseille, France; iLab-Spine - Laboratoire International en Imagerie et Biomécanique du Rachis, Marseille, France & Montréal, Canada
| | - Yvan Petit
- Department of Mechanical Engineering, École de Technologie Supérieure, 1100 Notre-Dame Street West, Montréal, Québec H3C 1K3, Canada; Research Center, Hôpital du Sacré-Coeur de Montréal, 5400 Gouin blvd, Montréal Québec, H4J 1C5, Canada; iLab-Spine - Laboratoire International en Imagerie et Biomécanique du Rachis, Marseille, France & Montréal, Canada
| |
Collapse
|
2
|
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.
Collapse
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
| |
Collapse
|
3
|
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.
Collapse
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:
| |
Collapse
|
4
|
Polak K, Czyż M, Ścigała K, Jarmundowicz W, Będziński R. Biomechanical characteristics of the porcine denticulate ligament in different vertebral levels of the cervical spine-preliminary results of an experimental study. J Mech Behav Biomed Mater 2014; 34:165-70. [PMID: 24583921 DOI: 10.1016/j.jmbbm.2014.02.010] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2013] [Revised: 01/24/2014] [Accepted: 02/05/2014] [Indexed: 12/27/2022]
Abstract
BACKGROUND Few studies exist on the mechanical properties of denticulate ligaments and none report the variation in these properties at different levels of the spine. The aim of this study was to perform an experimental determination of load-extension and stress-strain characteristics of the denticulate ligament and to establish if their properties change at different vertebral levels of the cervical spine. METHOD The study was carried out on a total of 98 porcine denticulate ligament samples dissected from seven fresh porcine cervical spinal cord specimens. All of the samples were subjected to an uniaxial tensile test at a speed of 2mm/min, during which the load-extension characteristics were registered. RESULTS The analysis revealed a decrease of the failure force in the caudal orientation indicated by significant differences between the C1 (1.04±0.41N) and C7 (0.55±0.12N) vertebral levels (P=0.037). The average ultimate force that broke the denticulate ligaments was 0.88N. The mean value of Young׳s modulus was 2.06MPa with a minimum of 1.31MPa for C7 and maximum of 2.46MPa for C5. CONCLUSIONS The values of the denticulate ligament failure force in samples from different cervical vertebrae levels differ significantly. The presented data should be taken into consideration during numerical modelling of the human cervical spinal cord.
Collapse
Affiliation(s)
- Katarzyna Polak
- Institute of Product and Process Innovation, Leuphana University Lueneburg, Germany; Division of Biomedical Engineering and Experimental Mechanics, Wroclaw University of Technology, Wroclaw, Poland.
| | - Marcin Czyż
- Department of Neurosurgery, Wroclaw Medical University, Wroclaw, Poland
| | - Krzysztof Ścigała
- Division of Biomedical Engineering and Experimental Mechanics, Wroclaw University of Technology, Wroclaw, Poland
| | | | - Romuald Będziński
- Division of Biomedical Engineering and Experimental Mechanics, Wroclaw University of Technology, Wroclaw, Poland
| |
Collapse
|