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Yoshizato H, Morimoto T, Nonaka T, Otani K, Kobayashi T, Nakashima T, Hirata H, Tsukamoto M, Mawatari M. Animal Model for Anterior Lumbar Interbody Fusion: A Literature Review. Spine Surg Relat Res 2024; 8:373-382. [PMID: 39131411 PMCID: PMC11310536 DOI: 10.22603/ssrr.2023-0262] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/24/2023] [Accepted: 12/22/2023] [Indexed: 08/13/2024] Open
Abstract
Lumbar interbody fusion (LIF) is a surgical procedure for treating lumbar spinal stenosis and deformities. It removes a spinal disc and insert a cage or bone graft to promote solid fusion. Extensive research on LIF has been supported by numerous animal studies, which are being developed to enhance fusion rates and reduce the complications associated with the procedure. In particular, the anterior approach is significant in LIF research and regenerative medicine studies concerning intervertebral discs, as it utilizes the disc and the entire vertebral body. Several animal models have been used for anterior LIF (ALIF), each with distinct characteristics. However, a comprehensive review of ALIF models in different animals is currently lacking. Medium-sized and large animals, such as dogs and sheep, have been employed as ALIF models because of their suitable spine size for surgery. Conversely, small animals, such as rats, are rarely employed as ALIF models because of anatomical challenges. However, recent advancements in surgical implants and techniques have gradually allowed rats in ALIF models. Ambitious studies utilizing small animal ALIF models will soon be conducted. This review aims to review the advantages and disadvantages of various animal models, commonly used approaches, and bone fusion rate, to provide valuable insights to researchers studying the spine.
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Affiliation(s)
- Hiromu Yoshizato
- Department of Orthopaedic Surgery, Faculty of Medicine, Saga University, Saga, Japan
| | - Tadatsugu Morimoto
- Department of Orthopaedic Surgery, Faculty of Medicine, Saga University, Saga, Japan
| | - Toshihiro Nonaka
- Department of Orthopaedic Surgery, Faculty of Medicine, Saga University, Saga, Japan
| | - Koji Otani
- Department of Orthopedic Surgery, Fukushima Medical University School of Medicine, Fukushima, Japan
| | | | - Takema Nakashima
- Department of Orthopaedic Surgery, JCHO Saga Central Hospital, Saga, Japan
| | - Hirohito Hirata
- Department of Orthopaedic Surgery, Faculty of Medicine, Saga University, Saga, Japan
| | - Masatsugu Tsukamoto
- Department of Orthopaedic Surgery, Faculty of Medicine, Saga University, Saga, Japan
| | - Masaaki Mawatari
- Department of Orthopaedic Surgery, Faculty of Medicine, Saga University, Saga, Japan
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Zehr JD, Quadrilatero J, Callaghan JP. Initiation and accumulation of loading induced changes to native collagen content and microstructural damage in the cartilaginous endplate. Spine J 2024; 24:161-171. [PMID: 37487932 DOI: 10.1016/j.spinee.2023.07.018] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/23/2023] [Revised: 07/12/2023] [Accepted: 07/19/2023] [Indexed: 07/26/2023]
Abstract
BACKGROUND CONTEXT Injury to the cartilaginous endplate (CEP) is linked to clinically relevant low back disorders, including intervertebral disc degeneration and pain reporting. Despite this link to clinical disorders, the CEP injury pathways and the modulating effect of mechanical loading parameters on the pace of damage accumulation remains poorly understood. PURPOSE This study examined the effect of cyclic loading on the initiation and accumulation of changes to native collagen content (type I, type II) and microstructural damage in the central region of cadaveric porcine CEPs. STUDY DESIGN In vitro longitudinal study. METHODS One hundred fourteen porcine cervical spinal units were included (N=6 per group). The study contained a control group (no cyclic loading) and 18 experimental groups that differed by loading duration (1,000, 3,000, 5,000 cycles), joint posture (flexed, neutral), and cyclic peak compression variation (10%, 20%, 40%). Multicolor immunofluorescence staining was used to quantify loading induced changes to type I (ie, subchondral bone) and type II (ie, endplate) native collagen content (fluorescence area, fluorescence intensity) and microstructural damage (pore area [transverse plane], void area along the CEP-bone border [sagittal plane]). RESULTS Significant main effects of loading duration and posture were observed for fluorescence area and fluorescence intensity of type I and II collagen. In the transverse plane, type II fluorescence area significantly decreased following 1,000 cycles (-12%), but a significant change in fluorescence intensity was not observed until 3,000 cycles (-17%). Type II fluorescence area (-14%) and intensity (-10%) were both significantly less in flexed postures compared to neutral. Similar trends were observed for type I collagen in the sagittal plane sections. Generally, significant changes to fluorescence area were accompanied by the development of microstructural voids along the endplate-subchondral bone border. CONCLUSIONS These findings demonstrate that microstructural damage beneath the endplate surface occurs before significant changes to the density of native type I and II collagen fibers. Although flexed postures were associated with greater and accelerated changes to native collagen content, the injury initiation mechanism appears similar to neutral. CLINICAL SIGNIFICANCE Neutral joint postures can delay the initiation and pace of microdamage accumulation in the CEP during low-to-moderate demand lifting tasks. Furthermore, the management of peak compression exposures appeared relevant only when a neutral posture was maintained. Therefore, clinical low back injury prevention and load management efforts should consider low back posture in parallel with applied joint forces.
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Affiliation(s)
- Jackie D Zehr
- Department of Kinesiology and Health Sciences, University of Waterloo, Waterloo, Ontario, Canada
| | - Joe Quadrilatero
- Department of Kinesiology and Health Sciences, University of Waterloo, Waterloo, Ontario, Canada
| | - Jack P Callaghan
- Department of Kinesiology and Health Sciences, University of Waterloo, Waterloo, Ontario, Canada.
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Amato MCM, Carneiro VM, Fernandes DS, de Oliveira RS. Intracranial Pressure Evaluation in Swine During Full-Endoscopic Lumbar Spine Surgery. World Neurosurg 2023; 179:e557-e567. [PMID: 37690580 DOI: 10.1016/j.wneu.2023.09.001] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2023] [Revised: 08/31/2023] [Accepted: 09/01/2023] [Indexed: 09/12/2023]
Abstract
BACKGROUND Neurological complications during full-endoscopic spine surgery (FESS) might be attributed to intracranial pressure (ICP) increase due to continuous saline infusion (CSI). Understanding CSI and ICP correlation might modify irrigation pump usage. This study aimed to evaluate invasive ICP during interlaminar FESS; correlate ICP with irrigation pump parameters (IPPs); evaluate ICP during saline outflow occlusion, commonly used to control bleeding and improve the surgeon's view; and, after durotomy, simulate accidental dural tear. METHODS Five swine were monitored, submitted to total intravenous anesthesia, and positioned ventrally. A parenchymal catheter was installed through a skull burr for ICP monitoring. Lumbar interlaminar FESS was performed until exposure of neural structures. CSI was used within progressively higher IPPs (A [60 mm Hg, 350 mL/minute] to D [150 mm Hg, 700 mL/minute]), and ICP was documented. During each IPP, different situations were grouped: intact dura with open channels (A1-D1) or occlusion test (A2-D2); dural tear with open channels (Ax1-Dx1) or occlusion test (Ax2-Dx2). ICP <20 mm Hg was defined as safe. RESULTS Basal average ICP was 8.1 mm Hg. Adjustment in total intravenous anesthesia or suspension of tests was necessary due to critical ICP or animal discomfort. It was safe to operate with all IPPs with opened drainage channels (A1-D1) even with dural tear (Ax1-Dx1). Several occlusion tests (A2-D2, Ax2-Dx2) caused ICP increase (e.g., 86.1 mm Hg) influenced by anesthetic state and hemodynamics. CONCLUSIONS During FESS, CSI might critically raise ICP. Keeping drainage channels open, with ideal anesthetic state, ICP remains safe even with high IPPs, despite dural tear. Drainage occlusions can quickly raise ICP, being even more severe with higher IPPs. Total intravenous anesthesia may protect from ICP increase and may allow longer drainage occlusion or higher IPPs.
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Affiliation(s)
- Marcelo Campos Moraes Amato
- Division of Neurosurgery, Department of Surgery and Anatomy, University Hospital, Ribeirão Preto Medical School, University of São Paulo, São Paulo, Brazil.
| | - Vinicius Marques Carneiro
- Division of Neurosurgery, Department of Surgery and Anatomy, University Hospital, Ribeirão Preto Medical School, University of São Paulo, São Paulo, Brazil
| | - Denylson Sanches Fernandes
- Division of Neurosurgery, Department of Surgery and Anatomy, University Hospital, Ribeirão Preto Medical School, University of São Paulo, São Paulo, Brazil
| | - Ricardo Santos de Oliveira
- Division of Neurosurgery, Department of Surgery and Anatomy, University Hospital, Ribeirão Preto Medical School, University of São Paulo, São Paulo, Brazil
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Wilke H, Betz VM, Kienle A. Biomechanical in vitro evaluation of the kangaroo spine in comparison with human spinal data. J Anat 2023; 243:128-137. [PMID: 36929138 PMCID: PMC10273331 DOI: 10.1111/joa.13852] [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: 06/02/2022] [Revised: 01/12/2023] [Accepted: 02/14/2023] [Indexed: 03/18/2023] Open
Abstract
On the basis of the kangaroo's pseudo-biped locomotion and its upright position, it could be assumed that the kangaroo might be an interesting model for spine research and that it may serve as a reasonable surrogate model for biomechanical in vitro tests. The purpose of this in vitro study was to provide biomechanical properties of the kangaroo spine and compare them with human spinal data from the literature. In addition, references to already published kangaroo anatomical spinal parameters will be discussed. Thirteen kangaroo spines from C4 to S4 were sectioned into single-motion segments. The specimens were tested by a spine tester under pure moments. The range of motion and neutral zone of each segment were determined in flexion and extension, right and left lateral bending and left and right axial rotation. Overall, we found greater flexibility in the kangaroo spine compared to the human spine. Similarities were only found in the cervical, lower thoracic and lumbar spinal regions. The range of motion of the kangaroo and human spines displayed comparable trends in the cervical (C4-C7), lower thoracic and lumbar regions independent of the motion plane. In the upper and middle thoracic regions, the flexibility of the kangaroo spine was considerably larger. These results suggested that the kangaroo specimens could be considered to be a surrogate, but only in particular cases, for biomechanical in vitro tests.
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Affiliation(s)
- Hans‐Joachim Wilke
- Institute of Orthopaedic Research and BiomechanicsTrauma Research Centre Ulm, University of UlmUlmGermany
| | - Volker Michael Betz
- Institute of Orthopaedic Research and BiomechanicsTrauma Research Centre Ulm, University of UlmUlmGermany
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Allais R, Capart A, Da Silva A, Boiron O. Biomechanical consequences of the intervertebral disc centre of rotation kinematics during lateral bending and axial rotation. Sci Rep 2023; 13:3172. [PMID: 36823433 PMCID: PMC9950088 DOI: 10.1038/s41598-023-29551-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/09/2022] [Accepted: 02/06/2023] [Indexed: 02/25/2023] Open
Abstract
The location of the instantaneous centre of rotation (ICR) of a lumbar unit has a considerable clinical importance as a spinal health estimator. Consequently, many studies have been conducted to measure or estimate the ICR during rotations in the three anatomical planes; however the results reported are widely scattered. Even if some inter-subjects variability is to be expected, such inconsistencies are likely explained by the differences in methods and experiments. Therefore, in this paper we seek to model three behaviours of the ICR during lateral bending and axial rotation based on results published in the literature. In order to assess the metabolic and mechanical sensibility to the assumption made on the ICR kinematics, we used a previously validated three dimensional non-linear poroelastic model of a porcine intervertebral disc to simulate physiological lateral and axial rotations. The impact of the geometry was also briefly investigated by considering a 11[Formula: see text] wedge angle. From our simulations, it appears that the hypothesis made on the ICR location does not significantly affect the critical nutrients concentrations but gives disparate predictions of the intradiscal pressure at the centre of the disc (variation up to 0.7 MPa) and of the displacement fields (variation up to 0.4 mm). On the contrary, the wedge angle does not influence the estimated intradiscal pressure but leads to minimal oxygen concentration decreased up to 33% and increased maximal lactate concentration up to 13%. While we can not settle on which definition of the ICR is more accurate, this work suggests that patient-specific modeling of the ICR is required and brings new insights that can be useful for the development of new tools or the design of surgical material such as total lumbar disc prostheses.
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Affiliation(s)
- Roman Allais
- CNRS, Centrale Marseille, IRPHE, Aix Marseille Univ, 13013, Marseille, France.
| | - Antoine Capart
- grid.462364.10000 0000 9151 9019Aix Marseille Univ, CNRS, Centrale Marseille, Institut Fresnel, 13013 Marseille, France
| | - Anabela Da Silva
- grid.462364.10000 0000 9151 9019Aix Marseille Univ, CNRS, Centrale Marseille, Institut Fresnel, 13013 Marseille, France
| | - Olivier Boiron
- grid.5399.60000 0001 2176 4817CNRS, Centrale Marseille, IRPHE, Aix Marseille Univ, 13013 Marseille, France
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Biomechanical evaluation of position and bicortical fixation of anterior lateral vertebral screws in a porcine model. Sci Rep 2023; 13:454. [PMID: 36624133 PMCID: PMC9829755 DOI: 10.1038/s41598-023-27433-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/14/2022] [Accepted: 01/02/2023] [Indexed: 01/10/2023] Open
Abstract
Although an anterior approach with anterior lateral screw fixation has been developed for stabilizing the thoracolumbar spine clinically, screw loosening still occurs. In this novel in vitro study, we attempted to elucidate the optimal screw position in the lateral lumbar vertebra and the effect of bicortical fixation. A total of 72 fresh-frozen lumbar vertebrae from L1-6 were harvested from 12 mature pigs and randomly assigned to two modalities: bicortical fixation (n = 36) and unicortical fixation (n = 36). Six groups of screw positions in the lateral vertebral body in each modality were designated as central-anterior, central-middle, central-posterior, lower-anterior, lower-middle, and lower- posterior; 6 specimens were used in each group. The correlations between screw fixation modalities, screw positions and axial pullout strength were analyzed. An appropriate screw trajectory and insertional depth were confirmed using axial and sagittal X-ray imaging prior to pullout testing. In both bicortical and unicortical fixation modalities, the screw pullout force was significantly higher in the posterior or middle position than in the anterior position (p < 0.05), and there was no significant differences between the central and lower positions. The maximal pullout forces from the same screw positions in unicortical fixation modalities were all significantly lower, decreases that ranged from 32.7 to 74%, than those in bicortical fixation modalities. Our study using porcine vertebrae showed that screws in the middle or posterior position of the lateral vertebral body had a higher pullout performance than those in the anterior position. Posteriorly positioned lateral vertebral screws with unicortical fixation provided better stability than anteriorly positioned screws with bicortical fixation.
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Duits A, Salvatori D, Schouten J, van Urk P, Gaalen SV, Ottink K, Öner C, Kruyt M. Preclinical model for lumbar interbody fusion in small ruminants: Rationale and guideline. J Orthop Translat 2023; 38:167-174. [DOI: 10.1016/j.jot.2022.10.006] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/18/2022] [Revised: 09/27/2022] [Accepted: 10/10/2022] [Indexed: 11/18/2022] Open
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Mechanically induced histochemical and structural damage in the annulus fibrosus and cartilaginous endplate: a multi-colour immunofluorescence analysis. Cell Tissue Res 2022; 390:59-70. [PMID: 35790585 DOI: 10.1007/s00441-022-03649-2] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2021] [Accepted: 06/02/2022] [Indexed: 11/02/2022]
Abstract
The annulus fibrosus (AF) and endplate (EP) are collagenous spine tissues that are frequently injured due to gradual mechanical overload. Macroscopic injuries to these tissues are typically a by-product of microdamage accumulation. Many existing histochemistry and biochemistry techniques are used to examine microdamage in the AF and EP; however, there are several limitations when used in isolation. Immunofluorescence may be sensitive to histochemical and structural damage and permits the simultaneous evaluation of multiple proteins-collagen I (COL I) and collagen II (COL II). This investigation characterized the histochemical and structural damage in initially healthy porcine spinal joints that were either unloaded (control) or loaded via biofidelic compression loading. The mean fluorescence area and mean fluorescence intensity of COL II significantly decreased (- 54.9 and - 44.8%, respectively) in the loaded AF (p ≤ 0.002), with no changes in COL I (p ≥ 0.471). In contrast, the EP displayed similar decreases in COL I and COL II fluorescence area (- 35.6 and - 37.7%, respectively) under loading conditions (p ≤ 0.027). A significant reduction (-31.1%) in mean fluorescence intensity was only observed for COL II (p = 0.043). The normalized area of pores was not altered on the endplate surface (p = 0.338), but a significant increase (+ 7.0%) in the void area was observed on the EP-subchondral bone interface (p = 0.002). Colocalization of COL I and COL II was minimal in all tissues (R < 0.34). In conclusion, the immunofluorescence analysis captured histochemical and structural damage in collagenous spine tissues, namely, the AF and EP.
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Fewster KM, Barrett JM, Callaghan JP. The Influence of Simulated Low Speed Vehicle Impacts and Posture on Passive Intervertebral Mechanics. Spine (Phila Pa 1976) 2022; 47:E362-E369. [PMID: 34431835 DOI: 10.1097/brs.0000000000004208] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/01/2023]
Abstract
STUDY DESIGN An in vitro biomechanics investigation exposing porcine functional spinal units (FSUs) to sudden impact loading although in a flexed, neutral, or extended posture. OBJECTIVE To investigate the combined effect of impact severity and postural deviation on intervertebral joint mechanics. SUMMARY OF BACKGROUND DATA To date, no in vitro studies have been conducted to explore lumbar tissue injury potential and altered mechanical properties from exposure to impact forces. Typically, after a motor vehicle collision, the cause of a reported acute onset of low back pain is difficult to identify, with potential soft tissue strain injury sites including the intervertebral disc, facet joint and highly innervated facet joint capsule ligament. METHODS Seventy-two porcine functional spinal units (36 C34, 36 C56), consisting of 2 adjacent vertebrae, ligaments, and the intervening intervertebral disc were included in the study. Each specimen was randomized to 1 of 3 experimental posture conditions (neutral, flexed, or extended) and assigned to 1 of 3 impact severities representing motor vehicle accident accelerations (4 g, 8 g, and 11 g). Before impact (pre) and after impact (post) flexion-extension and anterior-posterior shear neutral zone testing was completed. RESULTS A significant two-way interaction was observed between pre-post and impact severity for flexion-extension neutral zone length and stiffness and anterior-posterior shear neutral zone length and stiffness. This was a result of increasedneutral zone range and decreased neutral zone stiffness pre-post for the highest impact severity (11 g), regardless of posture. CONCLUSION Functional spinal units exposed to the highest severity impact (11 g) had significant neutral zone changes, with increases in joint laxity in flexion-extension and anterior-posterior shear and decreased stiffness, suggesting that soft tissue injury may have occurred. Despite observed main effects of impact severity, no influence of posture was observed.Level of Evidence: N/A.
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Affiliation(s)
- Kayla M Fewster
- Department of Kinesiology, University of Waterloo, Waterloo, ON, Canada
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A morphometric analysis of thoracolumbar vertebrae in goat by computed tomography. Vet Anim Sci 2022; 15:100233. [PMID: 35112012 PMCID: PMC8790494 DOI: 10.1016/j.vas.2022.100233] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
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A Comparative Biomechanical Analysis of the Impact of Different Configurations of Pedicle-Screw-Based Fixation in Thoracolumbar Compression Fracture. Appl Bionics Biomech 2022; 2022:3817097. [PMID: 35251301 PMCID: PMC8890884 DOI: 10.1155/2022/3817097] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/22/2021] [Accepted: 02/10/2022] [Indexed: 12/12/2022] Open
Abstract
The aim of this experimental study was to analyze the impact of applying different configurations of the transpedicular fixation system on selected mechanical parameters of the thoracolumbar spine under conditions of its instability (after simulated fracture). Five study groups were tested: physiological, with compression fracture of the vertebra, with two-segment fixation, with three-segment fixation, and with four-segment fixation. Each of the analyzed study groups was subjected to axial compression, flexion, and extension. Based on the conducted experimental tests, the mechanical parameters, i.e., stiffness coefficient and dissipation energy, were determined for all groups under consideration. The stiffness value of two-segment fixation is significantly lower than the physiological value (during flexion and extension). The use of long-segment fixation considered in two configurations (three- and four-segment fixation) may result in excessive stiffness of the system due to the high stiffness values achieved (approx. 25–30% higher than the physiological values in the case of compression and on average 60% higher in the case of flexion). The use of long-segment fixator design shows better results than short-segment fixation. Considering both biomechanical and clinical aspects, three-segment fixation seems to be a compromise solution as it saves the patient from more extensive stiffening of the spinal motion segments.
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Zehr JD, Callaghan JP. Reaction Forces and Flexion-Extension Moments Imposed On Functional Spinal Units with Constrained and Unconstrained in Vitro Testing Systems. J Biomech Eng 2021; 144:1129241. [PMID: 34897374 DOI: 10.1115/1.4053208] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2021] [Indexed: 11/08/2022]
Abstract
A mechanical goal of in vitro testing systems is to minimize differences between applied and actual forces and moments experienced by spinal units. This study quantified the joint reaction forces and reaction flexion-extension moments during dynamic compression loading imposed throughout the physiological flexion-extension range-of-motion. Constrained (fixed base) and unconstrained (floating base) testing systems were compared. Sixteen porcine spinal units were assigned to both testing groups. Following conditioning tests, specimens were dynamically loaded for 1 cycle with a 1 Hz compression waveform to a peak load of 1 kN and 2 kN while positioned in five different postures (neutral, 100% and 300% of the flexion and extension neutral zone), totalling ten trials per FSU. A six degree-of-freedom force and torque sensor was used to measure peak reaction forces and moments for each trial. Shear reaction forces were significantly greater (25.5 N - 85.7 N) when the testing system was constrained compared to unconstrained (p < 0.029). The reaction moment was influenced by posture (p = 0.037), particularly in C5C6 spinal units. In 300% extension (C5C6), the reaction moment was, on average, 9.9 Nm greater than the applied moment in both testing systems and differed from all other postures (p < 0.001). The reaction moment error was, on average, 0.45 Nm at all other postures. In conclusion, these findings demonstrate that comparable reaction moments can be achieved with unconstrained systems, but without inducing appreciable shear reaction forces.
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Affiliation(s)
- Jackie D Zehr
- Department of Kinesiology, University of Waterloo, Waterloo, Ontario, Canada
| | - Jack P Callaghan
- Department of Kinesiology, University of Waterloo, Waterloo, Ontario, Canada
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Fewster KM, Guo J, Zehr JD, Barrett JM, Laing AC, Callaghan JP. Strain Response in the Facet Joint Capsule During Physiological Joint Rotation and Translation Following a Simulated Impact Exposure: an in Vitro Porcine Model. J Biomech Eng 2021; 144:1129237. [PMID: 34897377 DOI: 10.1115/1.4053207] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/19/2021] [Indexed: 11/08/2022]
Abstract
Low back pain (LBP) is frequently reported following rear impact collisions. Knowledge of how the facet joint capsule (FJC) mechanically behaves before and after rear impact collisions may help explain LBP development despite negative radiographic evidence of gross tissue failure. This study quantified the Green strain tensor in the facet joint capsule during rotation and translation range-of-motion tests completed before and following an in vitro simulation of a rear impact collision. Eight FSUs (4 C3-C4, 4 C5-C6) were tested. Following a preload test, FSUs were flexed and extended at 0.5 degrees/second until an ±8 Nm moment was achieved. Anterior and posterior joint translation was then applied at 0.2 mm/s until a target ±400 N shear load was imposed. Markers were drawn on the facet capsule surface and their coordinates were tracked during pre- and post-impact range-of-motion tests. Strain was defined as the change in point configuration relative to the determined neutral joint posture. There were no significant differences (p > 0.05) observed in all calculated FJC strain components in rotation and translation before and after the simulated impact. Our results suggest that LBP development resulting from the initiation of strain-induced mechanoreceptors and nociceptors with the facet joint capsule is unlikely following a severe rear impact collision within the boundaries of physiological joint motion.
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Affiliation(s)
- Kayla M Fewster
- Department of Kinesiology, University of Waterloo, Waterloo, Ontario, Canada
| | - Joyce Guo
- Department of Kinesiology, University of Waterloo, Waterloo, Ontario, Canada
| | - Jackie D Zehr
- Department of Kinesiology, University of Waterloo, Waterloo, Ontario, Canada
| | - Jeff M Barrett
- Department of Kinesiology, University of Waterloo, Waterloo, Ontario, Canada
| | - Andrew C Laing
- Department of Kinesiology, University of Waterloo, Waterloo, Ontario, Canada
| | - Jack P Callaghan
- Department of Kinesiology, University of Waterloo, Waterloo, Ontario, Canada
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Kerr HL, Gee A, Fernandes RJR, Kanawati AJ, Jin W, Gurr KR, Bailey CS, Zdero R, Rasoulinejad P. Biomechanical comparison of 3 types of transdiscal fixation implants for fixing high-grade L5/S1 spine spondylolisthesis. Spine J 2021; 21:1587-1593. [PMID: 33933707 DOI: 10.1016/j.spinee.2021.04.017] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/25/2021] [Revised: 04/19/2021] [Accepted: 04/21/2021] [Indexed: 02/03/2023]
Abstract
BACKGROUND CONTEXT There are several options for the stabilization of high-grade lumbosacral spondylolisthesis including transdiscal screws, the Bohlman technique (transdiscal fibular strut) and the modified Bohlman technique (transdiscal titanium mesh cage). The choice of an optimum construct remains controversial; therefore, we endeavoured to study and compare the biomechanical performance of these 3 techniques. PURPOSE The aim of this study was to compare 3 types of transdiscal fixation biomechanically in an in vitro porcine lumbar-sacral spine model. STUDY DESIGN/SETTING Porcine cadaveric biomechanical study. METHODS 18 complete lumbar-sacral porcine spines were split into 3 repair groups, transdiscal screws (TS), Bohlman technique, and a modified Bohlman technique (MBT). Range of motion (L3 - S1) was measured in an intact and repaired state for flexion, extension, left/right lateral bending, and left/right torsion. To recreate a high-grade lumbosacral spondylolisthesis a bilateral L5/S1 facetectomy, removing the intervertebral disc completely, and the L5 body was displaced 50%-60% over the sacral promontory. Results were analyzed and compared to intact baseline measurements. Standard quasi-static moments (5 Nm) were applied in all modes. RESULTS All range of motion (ROM) were in reference to intact baseline values. TS had the lowest ROM in all modes (p=.006-.495). Statistical difference was found only in extension for TS vs. BT (p=.011) and TS vs. MBT (p=.014). No bone or implant failures occurred. CONCLUSION TS provided the lowest ROM in all modes of loading compared to Bohlman technique and MBT. Our study indicates that TS results in the most biomechanically stable construct. CLINICAL SIGNIFICANCE Knowledge of the biomechanical attributes of various constructs could aid physicians in choosing a surgical construct for their patients.
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Affiliation(s)
- Hui-Ling Kerr
- London Health Science Centre, Victoria Hospital, London, N6A 5W9, Canada; Dept. of Surgery (Div. of Orthopaedic Surgery), Western University, London, N6A 3K7, Canada; Dept. of Trauma and Orthopaedics, Gloucestershire Hospitals NHS Foundation Trust, GL53 7AN, Gloucestershire, UK
| | - Aaron Gee
- London Health Science Centre, Victoria Hospital, London, N6A 5W9, Canada.
| | - Renan J R Fernandes
- London Health Science Centre, Victoria Hospital, London, N6A 5W9, Canada; Dept. of Surgery (Div. of Orthopaedic Surgery), Western University, London, N6A 3K7, Canada
| | - Andrew J Kanawati
- London Health Science Centre, Victoria Hospital, London, N6A 5W9, Canada; Dept. of Surgery (Div. of Orthopaedic Surgery), Western University, London, N6A 3K7, Canada; Westmead Hospital, Sydney, New South Wales, NSW 2145, Australia
| | - Winston Jin
- London Health Science Centre, Victoria Hospital, London, N6A 5W9, Canada
| | - Kevin R Gurr
- London Health Science Centre, Victoria Hospital, London, N6A 5W9, Canada; Dept. of Surgery (Div. of Orthopaedic Surgery), Western University, London, N6A 3K7, Canada
| | - Christopher S Bailey
- London Health Science Centre, Victoria Hospital, London, N6A 5W9, Canada; Dept. of Surgery (Div. of Orthopaedic Surgery), Western University, London, N6A 3K7, Canada
| | - Radovan Zdero
- London Health Science Centre, Victoria Hospital, London, N6A 5W9, Canada; Dept. of Surgery (Div. of Orthopaedic Surgery), Western University, London, N6A 3K7, Canada; Dept. of Mechanical and Materials Engineering, Western University, London, N6A 3K7, Canada
| | - Parham Rasoulinejad
- London Health Science Centre, Victoria Hospital, London, N6A 5W9, Canada; Dept. of Surgery (Div. of Orthopaedic Surgery), Western University, London, N6A 3K7, Canada
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15
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Gkantsinikoudis N, Kapetanakis S, Magras I, Tsiridis E, Kritis A. Tissue-Engineering of Human Intervertebral Disc: A Concise Review. TISSUE ENGINEERING PART B-REVIEWS 2021; 28:848-860. [PMID: 34409867 DOI: 10.1089/ten.teb.2021.0090] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Intervertebral disc (IVD) represents a structure of crucial structural and functional importance for human spine. Pathology of IVD institutes a frequently encountered condition in current clinical practice. Degenerative Disc Disease (DDD), the principal clinical representative of IVD pathology, constitutes an increasingly diagnosed spinal disorder associated with substantial morbidity and mortality in recent years. Despite the considerable incidence and socioeconomic burden of DDD, existing treatment modalities including conservative and surgical methods have been demonstrated to provide a limited therapeutic effect, being not capable of interrupting or reversing natural progress of underlying disease. These limitations underline the requirement for development of novel, innovative and more effective therapeutic strategies for DDD management. Within this literature framework, compromised IVD replacement with a viable IVD construct manufactured with Tissue-Engineering (TE) methods has been recommended as a promising therapeutic strategy for DDD. Existing preliminary preclinical data demonstrate that proper combination of cells from various sources, different scaffold materials and appropriate signaling molecules renders manufacturing of whole-IVD tissue-engineered constructs a technically feasible process. Aim of this narrative review is to critically summarize current published evidence regarding particular aspects of IVD-TE, primarily emphasizing in providing researchers in this field with practicable knowledge in order to enhance clinical translatability of their research and informing clinical practitioners about the features and capabilities of innovative TE science in the field of IVD-TE.
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Affiliation(s)
- Nikolaos Gkantsinikoudis
- School of Medicine, Faculty of Health Sciences, Aristotle University of Thessaloniki (A.U.Th.), Department of Physiology and Pharmacology , Thessaloniki, Greece.,School of Medicine, Faculty of Health Sciences, Aristotle University of Thessaloniki (A.U.Th), cGMP Regenerative Medicine Facility, Department of Physiology and Pharmacology, Thessaloniki, Greece;
| | - Stylianos Kapetanakis
- Interbalkan European Medical Center, Spine Department and Deformities, Thessaloniki, Greece;
| | - Ioannis Magras
- AHEPA University General Hospital, Aristotle University of Thessaloniki, Department of Neurosurgery, Thessaloniki, Greece;
| | - Eleftherios Tsiridis
- Papageorgiou General Hospital, Aristotle University Medical School, Academic Orthopaedic Department, Thessaloniki Ring Road, Nea Efkarpia, Greece.,Aristotle University Thessaloniki, Balkan Center, Buildings A & B, Center of Orthopaedics and Regenerative Medicine (C.O.RE.), Center of Interdisciplinary Research and Innovation (C.I.R.I.), Thessaloniki, 10th km Thessaloniki-Thermi Rd, Greece;
| | - Aristeidis Kritis
- School of Medicine, Faculty of Health Sciences, Aristotle University of Thessaloniki (A.U.Th.), Department of Physiology and Pharmacology , Thessaloniki, Greece.,School of Medicine, Faculty of Health Sciences, Aristotle University of Thessaloniki (A.U.Th), cGMP Regenerative Medicine Facility, Department of Physiology and Pharmacology, Thessaloniki, Greece;
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Säteri T, Nurro J, Hätinen OP, Hakulinen M, Leinonen V, Elomaa AP. 'Ex Vivo Porcine Models Are Valid for Testing and Training Microsurgical Lumbar Decompression Techniques'. World Neurosurg 2021; 155:e64-e74. [PMID: 34380085 DOI: 10.1016/j.wneu.2021.07.147] [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: 03/26/2021] [Revised: 07/30/2021] [Accepted: 07/31/2021] [Indexed: 12/01/2022]
Abstract
BACKGROUND Spinal surgeries are the leading causes for patient settlement issues. Recent European Medical Device Regulations aims to reduce complications by enforcing that surgical tools are validated before clinical use. Human cadavers are favored in preclinical use, but due to anatomical variance, decay and scarce supply, alternative synthetic and animal models are used. This study evaluates the fidelity and validity of porcine models in training and assessment of microsurgical decompressive techniques in lumbar spine. METHODS Anatomical dimensions of ten human and five young pig spines were assessed from CT images. Novel 'en bloc' fresh-frozen ex vivo porcine model tissues' fidelity and validity for decompressive surgery was evaluated by three expert neurosurgeons, in comparison to other models. RESULTS The pig's anatomical dimensions were on average 11% smaller than in humans. The pig's L4-L5 was most alike humans and highest similarity was in lamina and spinous process widths, and skin to posterior longitudinal ligament distance. Dimensional variability was higher in humans (F = 19.06-0.56, p<0.05). The pig's tissues were felt as good as living patients and better than cadavers for skin, fascia, bone, facets, ligamentum flavum and dura, but poor for vessels (experts ICC=0.696-0.903). The pig models validity for assessing drills adverse features (friction, jitter, heating, and soft tissue trauma) were reported unanimously excellent. CONCLUSION Pigs are representative for assessing microsurgical decompression techniques in the lower lumbar spine. The novel 'en bloc' pig model can be an asset for industries and clinicians during assessment and training of new spinal techniques.
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Affiliation(s)
- Tuomas Säteri
- University of Eastern Finland, Faculty of Health Sciences, School of Medicine, Kuopio, Finland.
| | - Jussi Nurro
- University of Eastern Finland, AIV Institute, Kuopio, Finland; Saparo Translational Research Oy, Kuopio, Finland
| | | | | | - Ville Leinonen
- University of Eastern Finland, Faculty of Health Sciences, School of Medicine, Kuopio, Finland; Kuopio University Hospital, Department of Neurosurgery, Kuopio, Finland
| | - Antti-Pekka Elomaa
- University of Eastern Finland, Faculty of Health Sciences, School of Medicine, Kuopio, Finland; Kuopio University Hospital, Department of Neurosurgery, Kuopio, Finland; Kuopio University Hospital, Microsurgery Center www.microsurgerycenter.com, Kuopio, Finland
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17
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Induction of a representative idiopathic-like scoliosis in a porcine model using a multidirectional dynamic spring-based system. Spine J 2021; 21:1376-1386. [PMID: 33757871 DOI: 10.1016/j.spinee.2021.03.015] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/28/2020] [Revised: 03/09/2021] [Accepted: 03/11/2021] [Indexed: 02/03/2023]
Abstract
BACKGROUND CONTEXT Scoliosis is a 3D deformity of the spine in which vertebral rotation plays an important role. However, no treatment strategy currently exists that primarily applies a continuous rotational moment over a long period of time to the spine, while preserving its mobility. We developed a dynamic, torsional device that can be inserted with standard posterior instrumentation. The feasibility of this implant to rotate the spine and preserve motion was tested in growing mini-pigs. PURPOSE To test the quality and feasibility of the torsional device to induce the typical axial rotation of scoliosis while maintaining growth and mobility of the spine. STUDY DESIGN Preclinical animal study with 14 male, 7 month old Gottingen mini-pigs. Comparison of two scoliosis induction methods, with and without the torsional device, with respect to 3D deformity and maintenance of the scoliosis after removal of the implants. METHODS Fourteen mini-pigs received either a unilateral tether-only (n=6) or a tether combined with a contralateral torsional device (n=8). X-rays and CT-scans were made post-operative, at 8 weeks and at 12 weeks. Flexibility of the spine was assessed at 12 weeks. In 3 mini-pigs per condition, the implants were removed and the animals were followed until no further correction was expected. RESULTS At 12 weeks the tether-only group yielded a coronal Cobb angle of 16.8±3.3°For the tether combined with the torsional device this was 22.0±4.0°. The most prominent difference at 12 weeks was the axial rotation with 3.6±2.8° for the tether-only group compared to 18.1±4.6° for the tether-torsion group. Spinal growth and flexibility remained normal and comparable for both groups. After removal of the devices, the induced scoliosis reduced by 41% in both groups. There were no adverse tissue reactions, implant complications or infections. CONCLUSION The present study indicates the ability of the torsional device combined with a tether to induce a flexible idiopathic-like scoliosis in mini-pigs. The torsional device was necessary to induce the typical axial rotation found in human scoliosis. CLINICAL SIGNIFICANCE The investigated torsional device could induce apical rotation in a flexible and growing spine. Whether this may be used to reduce a scoliotic deformity remains to be investigated.
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18
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Boonsri B, Nganvongpanit K, Buddhachat K, Punyapornwithaya V, Kongtueng P, Kaewmong P, Kittiwattanawong K. Morphometric analysis of cervical vertebrae in some marine and land mammals. Anat Histol Embryol 2021; 50:812-825. [PMID: 34272750 DOI: 10.1111/ahe.12725] [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: 05/05/2021] [Revised: 07/02/2021] [Accepted: 07/05/2021] [Indexed: 11/28/2022]
Abstract
Bones or skeletal remains can be used to answer a number of questions related to species, sex, age or cause of death. However, studies involving vertebrae have been limited as most were performed on skulls or long bones. Here, we have stated the hypothesis that the morphometry of cervical vertebrae can be used for species identification and body size estimation among marine and land mammals. The cervical vertebrae from eight and 14 species of marine and land mammals were used to collect morphometric data. Cluster dendrogram, principal component analysis, discriminant analysis and linear regression were used to analyse the data. The results indicate that, based on an index of C4 to C7, there were 13 out of 22 species for which identity could be correctly predicted in 100% of the cases. The correlations between cervical vertebrae parameters (height, width and length of centrum) in marine (average R2 = 0.87, p < .01) and land (average R2 = 0.51, p < .01) mammals were observed. These results indicate that vertebral morphometrics could be used for species prediction and verification of body weight in both marine and land mammals.
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Affiliation(s)
- Burin Boonsri
- Department of Companion Animals and Wildlife Clinics, Faculty of Veterinary Medicine, Chiang Mai University, Chiang Mai, Thailand
| | - Korakot Nganvongpanit
- Department of Veterinary Biosciences and Public Health, Faculty of Veterinary Medicine, Chiang Mai University, Chiang Mai, Thailand.,Excellence Center in Veterinary Bioscience, Chiang Mai University, Chiang Mai, Thailand
| | - Kittisak Buddhachat
- Excellence Center in Veterinary Bioscience, Chiang Mai University, Chiang Mai, Thailand.,Department of Biology, Faculty of Science, Naresuan University, Phitsanulok, Thailand
| | - Veerasak Punyapornwithaya
- Department of Food Animal Clinic, Faculty of Veterinary Medicine, Chiang Mai University, Chiang Mai, Thailand
| | - Piyamat Kongtueng
- Central Laboratory, Faculty of Veterinary Medicine, Chiang Mai University, Chiang Mai, Thailand
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19
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McMorran JG, Gregory DE. The Influence of Axial Compression on the Cellular and Mechanical Function of Spinal Tissues; Emphasis on the Nucleus Pulposus and Annulus Fibrosus: A Review. J Biomech Eng 2021; 143:050802. [PMID: 33454730 DOI: 10.1115/1.4049749] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2020] [Indexed: 11/08/2022]
Abstract
In light of the correlation between chronic back pain and intervertebral disc (IVD) degeneration, this literature review seeks to illustrate the importance of the hydraulic response across the nucleus pulposus (NP)-annulus fibrosus (AF) interface, by synthesizing current information regarding injurious biomechanics of the spine, stemming from axial compression. Damage to vertebrae, endplates (EPs), the NP, and the AF, can all arise from axial compression, depending on the segment's posture, the manner in which it is loaded, and the physiological state of tissue. Therefore, this movement pattern was selected to illustrate the importance of the bracing effect of a pressurized NP on the AF, and how injuries interrupting support to the AF may contribute to IVD degeneration.
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Affiliation(s)
- John G McMorran
- Department of Kinesiology and Physical Education, Wilfrid Laurier University, 75 University Avenue West, Waterloo, ON N2 L 3C5
| | - Diane E Gregory
- Department of Kinesiology and Physical Education, Wilfrid Laurier University, 75 University Avenue West, Waterloo, ON N2 L 3C5; Department of Health Sciences, Wilfrid Laurier University, 75 University Avenue West, Waterloo, ON N2 L 3C5
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20
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Fewster KM, Zehr JD, Barrett JM, Laing AC, Callaghan JP. Exploring the influence of impact severity and posture on vertebral joint mechanics in an in-vitro porcine model. J Biomech 2021; 122:110479. [PMID: 33964574 DOI: 10.1016/j.jbiomech.2021.110479] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2020] [Revised: 02/24/2021] [Accepted: 04/19/2021] [Indexed: 11/18/2022]
Abstract
To date, no in vitro studies have been conducted to explore lumbar soft tissue injury potential and altered mechanical properties from exposure to impact forces. After a motor vehicle collision (MVC), the cause of reported acute onset low back pain is difficult to associate with potential soft tissue strain injury sites including the facet joint and innervated facet joint capsule ligament (FJC). Thus, the purpose of this investigation was to quantify intervertebral anterior-posterior (AP) translation and facet joint capsule strain under varying postures and impact severities. Seventy-two porcine spinal units were exposed to three levels of impact severity (4 g, 8 g, 11 g), and posture (Neutral, Flexion, Extension). Impacts were applied using a custom-built impact track that replicated parameters experienced in low to moderate speed rear-end MVCs. Flexion-extension and anterior-posterior shear neutral zone testing were completed prior to impact. AP intervertebral translation and the strain tensor of the facet capsule ligament were measured during impacts. A significant main effect of collision severity was observed for peak AP intervertebral translation (4 g-2.8 ±0.53 mm; 8 g-6.4 ±2.9 mm; 11 g-8.3 ±0.45 mm) and peak FJC shear strain (2.37% strain change from 4 g to 11 g impact severity). Despite observed main effects of impact severity, no influence of posture was observed. This lack of influence of posture and small FJC strain magnitudes suggest that the FJC does not appear to undergo injurious or permanent mechanical changes in response to low-to-moderate MVC impact scenarios.
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Affiliation(s)
- Kayla M Fewster
- Department of Kinesiology, University of Waterloo, Waterloo, ON, Canada
| | - Jackie D Zehr
- Department of Kinesiology, University of Waterloo, Waterloo, ON, Canada
| | - Jeff M Barrett
- Department of Kinesiology, University of Waterloo, Waterloo, ON, Canada
| | - Andrew C Laing
- Department of Kinesiology, University of Waterloo, Waterloo, ON, Canada
| | - Jack P Callaghan
- Department of Kinesiology, University of Waterloo, Waterloo, ON, Canada.
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21
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Taguchi T, Lopez MJ. An overview of de novo bone generation in animal models. J Orthop Res 2021; 39:7-21. [PMID: 32910496 PMCID: PMC7820991 DOI: 10.1002/jor.24852] [Citation(s) in RCA: 20] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/21/2019] [Revised: 08/27/2020] [Accepted: 09/02/2020] [Indexed: 02/04/2023]
Abstract
Some of the earliest success in de novo tissue generation was in bone tissue, and advances, facilitated by the use of endogenous and exogenous progenitor cells, continue unabated. The concept of one health promotes shared discoveries among medical disciplines to overcome health challenges that afflict numerous species. Carefully selected animal models are vital to development and translation of targeted therapies that improve the health and well-being of humans and animals alike. While inherent differences among species limit direct translation of scientific knowledge between them, rapid progress in ex vivo and in vivo de novo tissue generation is propelling revolutionary innovation to reality among all musculoskeletal specialties. This review contains a comparison of bone deposition among species and descriptions of animal models of bone restoration designed to replicate a multitude of bone injuries and pathology, including impaired osteogenic capacity.
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Affiliation(s)
- Takashi Taguchi
- Laboratory for Equine and Comparative Orthopedic Research, Department of Veterinary Clinical Sciences, School of Veterinary MedicineLouisiana State UniversityBaton RougeLouisianaUSA
| | - Mandi J. Lopez
- Laboratory for Equine and Comparative Orthopedic Research, Department of Veterinary Clinical Sciences, School of Veterinary MedicineLouisiana State UniversityBaton RougeLouisianaUSA
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22
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Zehr JD, Buchman-Pearle JM, Callaghan JP. Joint fatigue-failure: A demonstration of viscoelastic responses to rate and frequency loading parameters using the porcine cervical spine. J Biomech 2020; 113:110081. [PMID: 33217697 DOI: 10.1016/j.jbiomech.2020.110081] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2020] [Revised: 09/18/2020] [Accepted: 10/12/2020] [Indexed: 11/19/2022]
Abstract
Fatigue-failure in low back tissues is influenced by parameters of cyclic loading. Therefore, this study quantified the effect of loading rate and frequency on the number of tolerated compression cycles. Energy storage and vertical deformation were secondarily examined. Thirty-two porcine spinal units were randomly assigned to experimental groups that differed by loading rate (4.2 kN/s, 8.3 kN/s) and loading frequency (0.5 Hz, 1 Hz). Following preload and range-of-motion tests, specimens were cyclically loaded in a neutral posture until fatigue-failure occurred or 10800 cycles were tolerated. Macroscopic dissection was performed to identify the fracture morphology, and measurements of energy storage and vertical displacement were calculated throughout the specimen lifespan (1%, 10%, 50%, 90%, 99%). Given the differences in compression dose-force-time integral-between experimental conditions, the number of sustained cycles were assessed following linear and nonlinear dose-normalization via correction factors calculated from existing risk-exposure approximations. Without dose-normalization, an 8.3 kN/s loading rate and 0.5 Hz loading frequency reduced the fatigue lifetime by 3541 and 5977 cycles, respectively (p < 0.001). Linear and nonlinear dose-normalization resulted in a significant rate × frequency interaction (p < 0.001). For a 1 Hz loading frequency, the number of sustained loading cycles did not differ between loading rates (padj ≥ 0.988), but at 0.5 Hz, spinal units compressed at 8.3 kN/s sustained 99% (linear) and 97% (nonlinear) fewer cycles (padj < 0.001). These findings demonstrate that the interacting effects of loading frequency and loading rate on spinal fatigue-failure depend on the normalization of dose discrepancies between experimental groups.
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Affiliation(s)
- Jackie D Zehr
- Department of Kinesiology, University of Waterloo, Waterloo, Ontario, Canada
| | | | - Jack P Callaghan
- Department of Kinesiology, University of Waterloo, Waterloo, Ontario, Canada.
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23
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Use of longer sized screws is a salvage method for broken pedicles in osteoporotic vertebrae. Sci Rep 2020; 10:10441. [PMID: 32591573 PMCID: PMC7320151 DOI: 10.1038/s41598-020-67489-2] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/15/2020] [Accepted: 06/05/2020] [Indexed: 11/09/2022] Open
Abstract
Screw loosening due to broken pedicles is a common complication resulting from the insertion of screws either with inadequate diameters or into an osteoporotic pedicle. In this novel in vitro study, we tried to clarify the contribution of the pedicle to screw fixation and subsequent salvage strategies using longer or larger-diameter screws in broken pedicles. Sixty L4 fresh-frozen lumbar vertebrae harvested from mature pigs were designed as the normal-density group (n = 30) and decalcified as the osteoporosis group (n = 30). Three modalities were randomly assigned as intact pedicle (n = 30), semi-pedicle (n = 15), and non-pedicle (n = 15) in each group. Three sizes of polyaxial screws (diameter × length of 6.0 mm × 45 mm, 6.0 mm × 50 mm, and 6.5 mm × 45 mm) over five trials were used in each modality. The associations between bone density, pedicle modality and screw pullout strength were analyzed. After decalcification for 4 weeks, the area bone mineral density decreased to approximately 56% (p < 0.05) of the normal-density group, which was assigned as the osteoporosis group. An appropriate screw trajectory and insertional depth were confirmed using X-ray imaging prior to pullout testing in both groups. The pullout forces of larger-diameter screws (6.5 mm × 45 mm) and longer screws (6.0 mm × 50 mm) were significantly higher (p < 0.05) in the semi- and non-pedicle modalities in the normal-density group, whereas only longer screws (6.0 mm × 50 mm) had a significantly higher (p < 0.05) pullout force in the non-pedicle modalities in the osteoporosis group. The pedicle plays an important role in both the normal bone density group and the osteoporosis group, as revealed by analyzing the pullout force percentage contributed by the pedicle. Use of a longer screw would be a way to salvage a broken pedicle of osteoporotic vertebra.
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Cachon T, Hassoun R, Odet M, Massenzio M, Carozzo C, Ronel S, Lafon Y, Viguier E. Morphometric dimensions of the goat thoracolumbar vertebrae using digitized CT images. Comput Methods Biomech Biomed Engin 2020. [DOI: 10.1080/10255842.2020.1713505] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/24/2022]
Affiliation(s)
- T. Cachon
- Université de Lyon, VetAgro Sup, Marcy l’Etoile, France
| | - R. Hassoun
- Université de Lyon, VetAgro Sup, Marcy l’Etoile, France
| | - M. Odet
- Université de Lyon, Université Claude Bernard Lyon 1, IFSTTAR, Lyon, France
| | - M. Massenzio
- Université de Lyon, Université Claude Bernard Lyon 1, IFSTTAR, Lyon, France
| | - C. Carozzo
- Université de Lyon, VetAgro Sup, Marcy l’Etoile, France
| | - S. Ronel
- Université de Lyon, Université Claude Bernard Lyon 1, IFSTTAR, Lyon, France
| | - Y. Lafon
- Université de Lyon, Université Claude Bernard Lyon 1, IFSTTAR, Lyon, France
| | - E. Viguier
- Université de Lyon, VetAgro Sup, Marcy l’Etoile, France
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25
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Galvez M, Montoya CE, Fuentes J, Rojas GM, Asahi T, Currie W, Kuflik M, Chahin A. Error Measurement Between Anatomical Porcine Spine, CT Images, and 3D Printing. Acad Radiol 2020; 27:651-660. [PMID: 31326309 DOI: 10.1016/j.acra.2019.06.016] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/20/2019] [Revised: 06/27/2019] [Accepted: 06/27/2019] [Indexed: 01/25/2023]
Abstract
RATIONALE AND OBJECTIVES 3D printers are increasingly used in medical applications such as surgical planning, creation of implants and prostheses, and medical education. For the creation of reliable 3D printed models of the vertebral column, processing must be performed on CT images. This processing must be assessed and validated so that any error of the printed model can be recognized and minimized. MATERIAL AND METHODS In order to perform this validation, 10 CT scans of porcine lumbar spinal vertebra were used, which were then dissected and scanned again. CT image processing was performed to obtain a mesh and perform 3D printing. RESULTS There was no statistical difference among the four different levels of vertebrae measurements (first CT images, second CT images, anatomical piece of porcine bone and 3D printing of porcine bone; One Way repeated measure ANOVA, F < F_crit, p value > α = 0.05). The Intraclass Correlation also revealed a mean intraclass correlation coefficient (3,1) = 0.9553, which describes the reliability of all four levels in addition to the reliability of the data between porcine samples subjected to different levels of measurement. This shows that the average error is less than 1 mm. CONCLUSIONS The measurements of models created with 3D printers using the pipeline described in this paper have an average error of 0.60 mm with CT images and 0.73 mm with anatomical piece. Thus, 3D printed models accurately reflect in vivo bones and provide accurate 3D impressions to assist in surgical planning.
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26
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Zehr JD, Barrett JM, Fewster KM, Laing AC, Callaghan JP. Strain of the facet joint capsule during rotation and translation range-of-motion tests: an in vitro porcine model as a human surrogate. Spine J 2020; 20:475-487. [PMID: 31563579 DOI: 10.1016/j.spinee.2019.09.022] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/11/2019] [Revised: 09/24/2019] [Accepted: 09/24/2019] [Indexed: 02/03/2023]
Abstract
BACKGROUND CONTEXT Prior data about the modulating effects of lumbar spine posture on facet capsule strains are limited to small joint deviations. Knowledge of facet capsule strain during rotational and translational intervertebral joint motion (ie, large joint deviations) under physiological loading could be useful as it may help explain why visually normal lumbar spinal joints become painful. PURPOSE This study quantified the strain tensor of the facet capsule during rotation and translation range-of-motion tests. STUDY DESIGN/SETTING Strain was calculated in isolated porcine functional spinal units. Following a preload, each specimen underwent a flexion/extension rotation (F/E) followed by an anterior/posterior translation (A/P) range-of-motion test while under a 300 N compression load. METHODS Twenty porcine spinal units (10 C3-C4, 10 C5-C6) were tested. Joint flexion/extension was imposed by applying a ±8 Nm moment at a rate of 0.5°/s, and translation was facilitated by loading the caudal vertebra with a ±400 N shear force at a rate of 0.2 mm/s. Points were drawn on the exposed capsule surface and their coordinates were optically tracked throughout each test. Strain was calculated as the displacement of the point configuration with respect to the configuration in a neutral joint position. RESULTS Compared to a neutral posture, superior-inferior strain increased and decreased systematically during flexion and extension, respectively. Posterior displacement of the caudal vertebra by more than 1.3 mm was associated with negative strains, which was significantly lower than the +4.6% strain observed during anterior displacement (p≥.199). The shear strain associated with anterior translation was, on average, -1.1% compared to a neutral joint posture. CONCLUSIONS These results demonstrate that there is a combination of strain types within the facet capsule when spinal units are rotated and translated. The strains documented in this study did not reach the thresholds associated with nociception. CLINICAL RELEVANCE The magnitude of flexion-extension rotation and anterior-translation may glean insight into the facet capsule deformation response under low compression (300 N) loading scenarios. Further, intervertebral joint motion alone, even under low compression loading, does not appear to initiate a clinically relevant pain response in the lumbar facet capsule of a nondegenerated spinal joint.
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Affiliation(s)
- Jackie D Zehr
- Department of Kinesiology, University of Waterloo, Waterloo, Ontario, Canada
| | - Jeffery M Barrett
- Department of Kinesiology, University of Waterloo, Waterloo, Ontario, Canada
| | - Kayla M Fewster
- Department of Kinesiology, University of Waterloo, Waterloo, Ontario, Canada
| | - Andrew C Laing
- Department of Kinesiology, University of Waterloo, Waterloo, Ontario, Canada
| | - Jack P Callaghan
- Department of Kinesiology, University of Waterloo, Waterloo, Ontario, Canada.
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Abbasi H, Abbasi A. Using Porcine Cadavers as an Alternative to Human Cadavers for Teaching Minimally Invasive Spinal Fusion: Proof of Concept and Anatomical Comparison. Cureus 2019; 11:e6158. [PMID: 31777701 PMCID: PMC6857820 DOI: 10.7759/cureus.6158] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022] Open
Abstract
Training surgeons to perform minimally invasive spinal (MIS) surgery is difficult because there are few realistic alternatives to human cadavers which are expensive and require special handling. In this study we report a protocol for performing an MIS training course on a fresh porcine cadaver. We find that the porcine lumbar spine closely resembles the human spine in terms of the vertebral and discal anatomy. Notable differences include a lower disc height and shallower diameter. We obtained fresh porcine cadavers weighing 40-70 kg from local farmers that had been gutted and bled. We position the cadaver prone on a backboard and set up the operating room with biplanar fluoroscopy. During approach and cage insertion, we found that the tactile feedback obtained is realistic and allows surgeons to familiarize themselves with the procedure. Porcine cadavers were also an excellent tool for practicing pedicle screw fixation due to the larger pedicles. Five training courses involving eight surgeons noted that except for anatomical differences the training course was equivalent to training on human cadavers and unanimously preferred training on porcine cadavers to synthetic foam models. We conclude that porcine cadavers are a useful model for training surgeons in MIS surgery. Routine use of porcine cadavers may increase the availability of MIS surgery training.
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Affiliation(s)
- Hamid Abbasi
- Neurosurgery, Inspired Spine Health, Minneapolis, USA
| | - Ali Abbasi
- Internal Medicine, Pritzker School of Medicine, Chicago, USA
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Zehr JD, Tennant LM, Callaghan JP. Examining endplate fatigue failure during cyclic compression loading with variable and consistent peak magnitudes using a force weighting adjustment approach: an in vitro study. ERGONOMICS 2019; 62:1339-1348. [PMID: 31343393 DOI: 10.1080/00140139.2019.1648879] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/01/2019] [Accepted: 07/17/2019] [Indexed: 06/10/2023]
Abstract
Repetitive movement is common in many occupational contexts. Therefore, cumulative load is a widely recognised risk factor for lowback injury. This study quantified the effect of force weighting factors on cumulative load estimates and injury prediction during cyclic loading. Forty-eight porcine cervical spine motion segments were assigned to experimental groups that differed by average peak compression magnitude (30%, 50% and 70% of predicted tolerance) and amplitude variation (consistent, variable). Cyclic loading was performed at a frequency of 0.5 Hz until fatigue failure occurred. Weighting factors were determined and applied instantaneously. Inclusion of weighting factors resulted in statistically similar cumulative load estimates at injury between variable and consistent loading (p > .071). Further, survivorship was generally greater when the peak compression magnitude was consistent compared to variable. These results emphasise the importance of weighting factors as an equalisation tool for the evaluation of cumulative low back loading exposures in occupational contexts. Practitioner summary: Weighting factors can equalise the risk of injury based on compression magnitude. When weighted, the cumulative compression was similar between consistent and variable cyclic loading protocols, despite being significantly different when unweighted and having similar injury rates. Therefore, assessing representative occupational exposures without evaluating task performance variability may underestimate injury risk. Abbreviations: FSU: functional spinal unit; UCT: ultimate compression tolerance.
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Affiliation(s)
- Jackie D Zehr
- Department of Kinesiology, University of Waterloo , Waterloo , ON , Canada
| | - Liana M Tennant
- Department of Kinesiology, University of Waterloo , Waterloo , ON , Canada
| | - Jack P Callaghan
- Department of Kinesiology, University of Waterloo , Waterloo , ON , Canada
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Harper RA, Pfeiffer FM, Choma TJ. The minipig as a potential model for pedicle screw fixation: morphometry and mechanics. J Orthop Surg Res 2019; 14:246. [PMID: 31382997 PMCID: PMC6683400 DOI: 10.1186/s13018-019-1292-9] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/13/2019] [Accepted: 07/25/2019] [Indexed: 01/29/2023] Open
Abstract
Background While there are several different animal models for use in the characterization of spinal fixation, none have emerged as a definitive model for comparative studies in spinal fixation methods. The purpose of this study is to establish morphometric data of porcine vertebrae and to characterize the feasibility of pedicle screw fixation in porcine spines for potential comparative human study. Methods Four spines from 45 to 50 kg Hanford minipigs were cleaned of soft tissue and analyzed by computed tomography and dual-energy x-ray absorptiometry. Two 5 × 30-mm pedicle screws were placed in each vertebra and tested to failure using a combined moment-load protocol. Results Pedicle widths were measured from L6-T5. Widths ranged from 7.15 mm (T6) to 9.24 mm (T14). Posterior cortex to anterior cortex depth ranged from 25.9 to 32.6 mm. Mean bone mineral density was 1.0665 g/cm2 (range 1.139–1.016). Force-to-failure demonstrated mean 1171.40 N (+ 115.34). Conclusion Our baseline morphometric and compositional data demonstrate that porcine vertebrae can serve as a useful model for comparative studies due to their similar pedicle widths and bone mineral density to the human vertebra. This biomechanical data could provide a baseline comparison for future studies. This study also suggests that the minipig could be a suitable model for comparative studies due to similarities in pedicle width and bone mineral density to the human vertebrae.
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Affiliation(s)
- Robert A Harper
- Department of Orthopedic Surgery, University of California-Davis, 4860 Y Street, Sacramento, CA, 95817, USA
| | - Ferris M Pfeiffer
- Department of Biological Engineering, University of Missouri, 247 Ag Engineering Building, Columbia, MO, 65211, USA
| | - Theodore J Choma
- Department of Orthopaedic Surgery, University of Missouri, 1100 Virginia Avenue DC953.00, Columbia, MO, 65212, USA.
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Biomechanical analysis of pedicle screw density in posterior spine instrumentation. CURRENT ORTHOPAEDIC PRACTICE 2019. [DOI: 10.1097/bco.0000000000000778] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
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Amato MCM, Aprile BC, de Oliveira CA, Carneiro VM, de Oliveira RS. Experimental Model for Interlaminar Endoscopic Spine Procedures. World Neurosurg 2019; 129:55-61. [PMID: 31152884 DOI: 10.1016/j.wneu.2019.05.199] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/07/2019] [Revised: 05/22/2019] [Accepted: 05/23/2019] [Indexed: 11/15/2022]
Abstract
BACKGROUND Endoscopic spinal surgery is becoming quite popular, and the pursuit of a training model to improve surgeons' skills is imperative to overcome the limited availability of human cadavers. Our goal was to determine whether the porcine spine could be a representative model for learning and practicing interlaminar percutaneous endoscopic lumbar procedures (IL-PELPs). METHODS Lumbar and cervical segments of the porcine cadaver spine were used for the IL-PELP. We have described the technical notes on the difficulties of the procedure and the relevant anatomical features. To endorse the porcine cadaver for this procedure, 5 neurosurgeons underwent 1 day of training and completed a survey. RESULTS The porcine lumbar spine has small interlaminar windows, and laminectomy is necessary, mimicking the translaminar approaches for higher human lumbar spine levels. The porcine cervical spine has wide and high interlaminar windows and mimics the human L5-S1 interlaminar approach. Entering the spinal canal with the working sheath and endoscope and training the rotation maneuver to access the disc space is only possible in the lumbar segment. It was possible to perform flavectomy and to identify and dissect the dural sac and nerve root in both the lumbar and cervical spine. The neurosurgeons considered the porcine model of good operability and, although different, possible to apply in humans. CONCLUSIONS The porcine spine is an effective and representative model for learning and practicing IL-PELPs. Although the described anatomical differences should be known, they did not interfere in performing the main surgical steps and maneuvers for IL-PELPs in the porcine model.
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Affiliation(s)
| | | | | | - Vinicius Marques Carneiro
- Division of Neurosurgery, Department of Surgery and Anatomy, University Hospital, Ribeirão Preto Medical School, University of São Paulo, Ribeirão Preto, Brazil
| | - Ricardo Santos de Oliveira
- Division of Neurosurgery, Department of Surgery and Anatomy, University Hospital, Ribeirão Preto Medical School, University of São Paulo, Ribeirão Preto, Brazil
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Zehr JD, Tennant LM, Callaghan JP. Incorporating loading variability into in vitro injury analyses and its effect on cumulative compression tolerance in porcine cervical spine units. J Biomech 2019; 88:48-54. [PMID: 30904332 DOI: 10.1016/j.jbiomech.2019.03.011] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/24/2018] [Revised: 03/07/2019] [Accepted: 03/10/2019] [Indexed: 10/27/2022]
Abstract
During repetitive movement, low-back loading exposures are inherently variable in magnitude. The current study aimed to investigate how variation in successive compression exposures influences cumulative load tolerance in the spine. Forty-eight porcine cervical spine units were randomly assigned to one of six combinations of mean peak compression force (30%, 50%, 70% of the predicted tolerance) and loading variation (consistent peak amplitude, variable peak amplitude). Following preload and passive range-of-motion tests, specimens were positioned in a neutral posture and then cyclically loaded in compression until failure occurred or the maximum 12 h duration was reached. Specimens were dissected to classify macroscopic injury and measurements of cumulative load, cycles, and height loss sustained at failure were calculated. Statistical comparisons were made between loading protocols within each normalized compression group. A significant loading variation × compression interaction was demonstrated for cumulative load (p = 0.026) and cycles to failure (p = 0.021). Cumulative compression was reduced under all normalized compression loads (30% p = 0.016; 50% p = 0.030; 70% p = 0.020) when variable loading was incorporated. The largest reduction was by 33% and occurred in the 30% compression group. The number of sustained cycles was reduced by 31% (p = 0.017), 72% (p = 0.030), and 76% (p = 0.009) under normalized compression loads of 30%, 50%, and 70%, respectively. These findings suggest that variation in compression exposures interact to reduce cumulative compression tolerance of the spine and could elevate low-back injury risk during time-varying repetitive tasks.
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Affiliation(s)
- Jackie D Zehr
- Department of Kinesiology, University of Waterloo, Waterloo, Ontario, Canada
| | - Liana M Tennant
- Department of Kinesiology, University of Waterloo, Waterloo, Ontario, Canada
| | - Jack P Callaghan
- Department of Kinesiology, University of Waterloo, Waterloo, Ontario, Canada.
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Morphometric Analysis of the Lumbar Vertebrae Concerning the Optimal Screw Selection for Transpedicular Stabilization. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2019; 1133:83-96. [PMID: 30680647 DOI: 10.1007/5584_2018_324] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
Transpedicular stabilization is a frequently used spinal surgery for fractures, degenerative changes, or neoplastic processes. Improper screw fixation may cause substantial vascular or neurological complications. This study seeks to define detailed morphometric measurements of the pedicle (height, width, and surface area) in the aspects of screw length and girth selection and the trajectory of its implantation, i.e., sagittal and transverse angle of placement. The study was based on CT examinations of 100 Caucasian patients (51 women and 49 men) aged 27-75 with no anatomical, degenerative, or post-traumatic spine changes. The results were stratified by gender and body side, and they were counter compared with the available literature database. Pedicle height decreased from L1 to L4, ranging from 15.9 to 13.3 mm. Pedicle width increased from L1 to L5, extending from 6.1 to 13.2 mm. Pedicle surface area increased from L1 to L5, ranging from 63 to 140 mm2. Distance from the point of entry into the pedicle to the anterior surface of the vertebral body, defining the maximum length of a transpedicular screw, varied from 54.0 to 50.2 mm. Variations concerning body sides were inappreciable. A transverse angle of screw trajectory extended from 20° to 32°, shifting caudally from L1 to L5, with statistical differences in the L3-L5 segments. A sagittal angle varied from 10° to 12°, without such definite relations. We conclude that the L1 and L2 segments display the most distinct morphometric similarities, while the greatest differences, in both genders, are noted for L3, L4, and L5. The findings enable the recommendation of the following screw diameters: 4 mm for L1-L2, 5 mm for L3, 6 mm for L4-L5, and the length of 50 mm. We believe the study has extended clinical knowledge on lumbar spine morphometry, essential in the training physicians engaged in transpedicular stabilization.
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Amato MCM, Aprile BC, Oliveira CAD, Carneiro VM, Oliveira RSD. Experimental model for transforaminal endoscopic spine. Acta Cir Bras 2018; 33:1078-1086. [DOI: 10.1590/s0102-865020180120000005] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2018] [Accepted: 11/05/2018] [Indexed: 11/21/2022] Open
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O'Leary SA, Paschos NK, Link JM, Klineberg EO, Hu JC, Athanasiou KA. Facet Joints of the Spine: Structure–Function Relationships, Problems and Treatments, and the Potential for Regeneration. Annu Rev Biomed Eng 2018; 20:145-170. [DOI: 10.1146/annurev-bioeng-062117-120924] [Citation(s) in RCA: 34] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
The zygapophysial joint, a diarthrodial joint commonly referred to as the facet joint, plays a pivotal role in back pain, a condition that has been a leading cause of global disability since 1990. Along with the intervertebral disc, the facet joint supports spinal motion and aids in spinal stability. Highly susceptible to early development of osteoarthritis, the facet is responsible for a significant amount of pain in the low-back, mid-back, and neck regions. Current noninvasive treatments cannot offer long-term pain relief, while invasive treatments can relieve pain but fail to preserve joint functionality. This review presents an overview of the facet in terms of its anatomy, functional properties, problems, and current management strategies. Furthermore, this review introduces the potential for regeneration of the facet and particular engineering strategies that could be employed as a long-term treatment.
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Affiliation(s)
- Siobhan A. O'Leary
- Department of Biomedical Engineering, University of California, Davis, California 95616, USA
| | - Nikolaos K. Paschos
- Department of Orthopedic Surgery, Division of Sports Medicine, Boston Children's Hospital, Harvard Medical School, Massachusetts 02115, USA
| | - Jarrett M. Link
- Department of Biomedical Engineering, University of California, Irvine, California 92617, USA
| | - Eric O. Klineberg
- Department of Orthopaedic Surgery, University of California, Davis, Sacramento, California 95816, USA
| | - Jerry C. Hu
- Department of Biomedical Engineering, University of California, Irvine, California 92617, USA
| | - Kyriacos A. Athanasiou
- Department of Biomedical Engineering, University of California, Irvine, California 92617, USA
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Biomechanical response of intact, degenerated and repaired intervertebral discs under impact loading – Ex-vivo and In-Silico investigation. J Biomech 2018; 70:26-32. [DOI: 10.1016/j.jbiomech.2018.01.026] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/16/2017] [Revised: 01/09/2018] [Accepted: 01/14/2018] [Indexed: 01/30/2023]
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Danesi V, Erani P, Brandolini N, Juszczyk MM, Cristofolini L. Effect of the In Vitro Boundary Conditions on the Surface Strain Experienced by the Vertebral Body in the Elastic Regime. J Biomech Eng 2017; 138:2543312. [PMID: 27496676 DOI: 10.1115/1.4034383] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/17/2016] [Indexed: 11/08/2022]
Abstract
The vertebral strength and strain can be assessed in vitro by both using isolated vertebrae and sets of three adjacent vertebrae (the central one is loaded through the disks). Our goal was to elucidate if testing single-vertebra-specimens in the elastic regime provides different surface strains to three-vertebrae-segments. Twelve three-vertebrae sets were extracted from thoracolumbar human spines. To measure the principal strains, the central vertebra of each segment was prepared with eight strain-gauges. The sets were tested mechanically, allowing comparison of the surface strains between the two boundary conditions: first when the same vertebra was loaded through the disks (three-vertebrae-segment) and then with the endplates embedded in cement (single-vertebra). They were all subjected to four nondestructive tests (compression, traction, torsion clockwise, and counterclockwise). The magnitude of principal strains differed significantly between the two boundary conditions. For axial loading, the largest principal strains (along vertebral axis) were significantly higher when the same vertebra was tested isolated compared to the three-vertebrae-segment. Conversely, circumferential strains decreased significantly in the single vertebrae compared to the three-vertebrae-segment, with some variations exceeding 100% of the strain magnitude, including changes from tension to compression. For torsion, the differences between boundary conditions were smaller. This study shows that, in the elastic regime, when the vertebra is loaded through a cement pot, the surface strains differ from when it is loaded through the disks. Therefore, when single vertebrae are tested, surface strain should be taken with caution.
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Cachon T, Pillard P, Odent T, Carozzo C, Viguier E. Safe corridor for the implantation of thoracolumbar pedicle screws in growing pigs: A morphometric study. PLoS One 2017; 12:e0184857. [PMID: 29059193 PMCID: PMC5653201 DOI: 10.1371/journal.pone.0184857] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/25/2016] [Accepted: 09/02/2017] [Indexed: 12/17/2022] Open
Abstract
The pig spine is widely used as a large animal model for preclinical research in human medicine to test new spinal implants and surgical procedures. Among them, pedicle screw is one of the most common method of fixation of those implants. However, the pedicle of the porcine vertebra is not as well defined and not as large as the pedicle of the human vertebra. Therefore, the position of the screw should be adapted to the pig and not merely transposed based on the literature on humans. The purpose of this study is to determine the characteristics of the optimum implantation corridors for pedicle screws in the thoracolumbar spine of piglets of different ages using computed tomography (CT) and to determine the size and length of these corridors in pigs of different ages. CT scans from five groups of age: 6, 10, 14, 18, and 26 weeks were reviewed. For each thoracolumbar vertebrae, the pedicle width, pedicle axis length, and the pedicle angle was measured for the left and right pedicle. A total of 326 thoracic vertebrae and 126 lumbar vertebrae were included in the study. Pedicles are statistically larger but not longer for the lumbar vertebrae. An important variation of the pedicle angle is observed along the spine. In all pigs, an abrupt modification of the pedicle angle between T10 and T11 was observed, which corresponds to the level of the anticlinal vertebra which is the vertebra for which the spinous process is nearly perpendicular to the vertebral body. In conclusion, this study provides a quantitative database of pedicle screw implantation corridors in pigs of different ages. When using pedicle screws in experimental studies in pigs, these results should be considered for selecting the most suitable implants for the study but also to ensure a correct and safer screw position. Improving study procedures may limit postoperative complications and pain, thereby limiting the use of live animals.
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Affiliation(s)
- Thibaut Cachon
- Unité ICE (USPS 2016-A104.) Campus Vétérinaire de Lyon-VetAgro-Sup, MARCY L’ETOILE, FRANCE
- * E-mail:
| | - Paul Pillard
- Unité ICE (USPS 2016-A104.) Campus Vétérinaire de Lyon-VetAgro-Sup, MARCY L’ETOILE, FRANCE
| | - Thierry Odent
- CHU Tours - Hôpital d'enfants Clocheville- Service de Chirurgie Orthopédique pédiatrique, TOURS, FRANCE
| | - Claude Carozzo
- Unité ICE (USPS 2016-A104.) Campus Vétérinaire de Lyon-VetAgro-Sup, MARCY L’ETOILE, FRANCE
| | - Eric Viguier
- Unité ICE (USPS 2016-A104.) Campus Vétérinaire de Lyon-VetAgro-Sup, MARCY L’ETOILE, FRANCE
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Reitmaier S, Graichen F, Shirazi-Adl A, Schmidt H. Separate the Sheep from the Goats: Use and Limitations of Large Animal Models in Intervertebral Disc Research. J Bone Joint Surg Am 2017; 99:e102. [PMID: 28976436 DOI: 10.2106/jbjs.17.00172] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/01/2023]
Abstract
Approximately 5,168 large animals (pigs, sheep, goats, and cattle) were used for intervertebral disc research in identified studies published between 1985 and 2016. Most of the reviewed studies revealed a low scientific impact, a lack of sound justifications for the animal models, and a number of deficiencies in the documentation of the animal experimentation. The scientific community should take suitable measures to investigate the presumption that animal models have translational value in intervertebral disc research. Recommendations for future investigations are provided to improve the quality, validity, and usefulness of animal studies for intervertebral disc research. More in vivo studies are warranted to comprehensively evaluate the suitability of animal models in various applications and help place animal models as an integral, complementary part of intervertebral disc research.
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Affiliation(s)
- Sandra Reitmaier
- 1Julius Wolff Institute, Charité-Universitätsmedizin Berlin, Berlin, Germany 2École Polytechnique, Montréal, Canada
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Cuellar CA, Mendez AA, Islam R, Calvert JS, Grahn PJ, Knudsen B, Pham T, Lee KH, Lavrov IA. The Role of Functional Neuroanatomy of the Lumbar Spinal Cord in Effect of Epidural Stimulation. Front Neuroanat 2017; 11:82. [PMID: 29075183 PMCID: PMC5642185 DOI: 10.3389/fnana.2017.00082] [Citation(s) in RCA: 30] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2017] [Accepted: 09/07/2017] [Indexed: 01/07/2023] Open
Abstract
In this study, the neuroanatomy of the swine lumbar spinal cord, particularly the spatial orientation of dorsal roots was correlated to the anatomical landmarks of the lumbar spine and to the magnitude of motor evoked potentials during epidural electrical stimulation (EES). We found that the proximity of the stimulating electrode to the dorsal roots entry zone across spinal segments was a critical factor to evoke higher peak-to-peak motor responses. Positioning the electrode close to the dorsal roots produced a significantly higher impact on motor evoked responses than rostro-caudal shift of electrode from segment to segment. Based on anatomical measurements of the lumbar spine and spinal cord, significant differences were found between L1-L4 to L5-L6 segments in terms of spinal cord gross anatomy, dorsal roots and spine landmarks. Linear regression analysis between intersegmental landmarks was performed and L2 intervertebral spinous process length was selected as the anatomical reference in order to correlate vertebral landmarks and the spinal cord structures. These findings present for the first time, the influence of spinal cord anatomy on the effects of epidural stimulation and the role of specific orientation of electrodes on the dorsal surface of the dura mater in relation to the dorsal roots. These results are critical to consider as spinal cord neuromodulation strategies continue to evolve and novel spinal interfaces translate into clinical practice.
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Affiliation(s)
- Carlos A Cuellar
- Department of Neurologic Surgery, Mayo ClinicRochester, MN, United States
| | - Aldo A Mendez
- Department of Neurologic Surgery, Mayo ClinicRochester, MN, United States
| | - Riazul Islam
- Department of Neurologic Surgery, Mayo ClinicRochester, MN, United States
| | - Jonathan S Calvert
- Mayo Clinic Graduate School of Biomedical Sciences, Mayo ClinicRochester, MN, United States
| | - Peter J Grahn
- Department of Neurologic Surgery, Mayo ClinicRochester, MN, United States
| | - Bruce Knudsen
- Department of Neurologic Surgery, Mayo ClinicRochester, MN, United States
| | - Tuan Pham
- Department of Biological Sciences, Lehigh UniversityBethlehem, PA, United States
| | - Kendall H Lee
- Department of Neurologic Surgery, Mayo ClinicRochester, MN, United States.,Department of Physical Medicine and Rehabilitation, Mayo ClinicRochester, MN, United States.,Department of Physiology and Biomedical Engineering, Mayo ClinicRochester, MN, United States
| | - Igor A Lavrov
- Department of Neurologic Surgery, Mayo ClinicRochester, MN, United States.,Department of Physiology and Biomedical Engineering, Mayo ClinicRochester, MN, United States.,Institute of Fundamental Medicine and Biology, Kazan Federal UniversityKazan, Russia
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Abstract
STUDY DESIGN Surgical approach development in an animal model, and a prospective study comparing clinical outcomes between novel and conventional approaches in thoracolumbar burst fracture fixation. OBJECTIVE To investigate the feasibility of a less-invasive retroperitoneal approach to the lumbar spine in a sheep model and to compare the clinical outcomes of anterior reconstruction in the treatment of thoracolumbar burst fractures using novel and conventional approaches. SUMMARY OF BACKGROUND DATA The anterior retroperitoneal lumbar approach is well established for anterior lumbar surgical procedures in both humans and animal models. However, potential concerns include the increased risk of complications such as soft-tissue trauma, and extended periods of rehabilitation postoperatively. MATERIALS AND METHODS A less-invasive retroperitoneal approach was designed in a sheep model with minimal soft-tissue dissection to keep the abdominal and paravertebral muscles intact. Eight sheep underwent anterior lumbar interbody fusion using this approach. In the clinical study, 48 patients with thoracolumbar burst fractures underwent anterior decompression and reconstruction. The less-invasive approach and conventional approach were applied in 12 and 36 cases, respectively. The clinical outcomes during the minimum 12-month follow-up of the 2 groups were compared. RESULTS With the less-invasive approach, anterior lumbar interbody fusion was accomplished in all sheep, and no surgical complications were observed. In the clinical study, operation time, blood loss, and duration of hospitalization were comparable between 2 groups. Using the less-invasive approach decreased the length of incision, 3-day postoperative visual analogue scale score, postoperative independent standing, and narcotic-dependent duration. No surgical complications were observed in either group. CONCLUSIONS Our results and early experience suggests that the less-invasive retroperitoneal approach is safe and effective for anterior lumbar surgery. Compared with the conventional approach, significantly better postoperative rehabilitation and abdominal muscle preservation were seen with this novel approach.
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Moon YJ, Kim JK, Oh HG, Kang JH, Park GJ, Lee KB. An Anesthesia, Surgery, and Harvest Method for the Evaluation of Transpedicular Screws Using an In Vivo Porcine Lumbar Spine Model. J Vis Exp 2017. [PMID: 28605377 DOI: 10.3791/55225] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/31/2022] Open
Abstract
Pedicle screw fixation is the gold standard for the treatment of spinal diseases. However, many studies have reported the issue of loosening pedicle screws after spinal surgery, which is a serious concern. To address this problem, diverse types of pedicle screws have been examined to identify those with good fixation strength and osseointegration in spine bone. The porcine spine is a good alternative for the human spine in the evaluation of pedicle screws due to the anatomical size, mechanical characteristics, and cost. Although several studies have reported that pedicle screws are efficient in the porcine model, no study has described detailed protocols for the evaluation of a pedicle screw using the porcine model. Here, we describe a detailed method for evaluating transpedicular screws using an in vivo porcine lumbar spine model. The technical details for anesthesia, spine surgery, and harvest provided here will facilitate with the evaluation of the transpedicular screw fixation model.
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Affiliation(s)
- Young Jae Moon
- Department of Orthopaedic Surgery, Chonbuk National University School of Medicine, Chonbuk National University Hospital
| | - Jong-Kil Kim
- Department of Orthopaedic Surgery, University of Seonam College of Medicine, Presbyterian Medical Center
| | | | - Ji-Hun Kang
- Department of Emergency Medicine, Inje University Busan Paik Hospital
| | - Gun-Joo Park
- Department of Orthopaedic Surgery, Chonbuk National University School of Medicine, Chonbuk National University Hospital
| | - Kwang-Bok Lee
- Department of Orthopaedic Surgery, Chonbuk National University School of Medicine, Chonbuk National University Hospital;
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Schomberg DT, Miranpuri GS, Chopra A, Patel K, Meudt JJ, Tellez A, Resnick DK, Shanmuganayagam D. Translational Relevance of Swine Models of Spinal Cord Injury. J Neurotrauma 2017; 34:541-551. [DOI: 10.1089/neu.2016.4567] [Citation(s) in RCA: 28] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Affiliation(s)
- Dominic T. Schomberg
- Biomedical and Genomic Research Group, Department of Animal Sciences, University of Wisconsin–Madison, Wisconsin
| | - Gurwattan S. Miranpuri
- Department of Neurological Surgery, University of Wisconsin School of Medicine and Public Health, Madison, Wisconsin
| | - Abhishek Chopra
- Department of Neurological Surgery, University of Wisconsin School of Medicine and Public Health, Madison, Wisconsin
| | - Kush Patel
- Department of Neurological Surgery, University of Wisconsin School of Medicine and Public Health, Madison, Wisconsin
| | - Jennifer J. Meudt
- Biomedical and Genomic Research Group, Department of Animal Sciences, University of Wisconsin–Madison, Wisconsin
| | | | - Daniel K. Resnick
- Department of Neurological Surgery, University of Wisconsin School of Medicine and Public Health, Madison, Wisconsin
| | - Dhanansayan Shanmuganayagam
- Biomedical and Genomic Research Group, Department of Animal Sciences, University of Wisconsin–Madison, Wisconsin
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Nikkhoo M, Wang JL, Abdollahi M, Hsu YC, Parnianpour M, Khalaf K. A regenerative approach towards recovering the mechanical properties of degenerated intervertebral discs: Genipin and platelet-rich plasma therapies. Proc Inst Mech Eng H 2016; 231:127-137. [PMID: 28019241 DOI: 10.1177/0954411916681597] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
Abstract
Degenerative disc disease, associated with discrete structural changes in the peripheral annulus and vertebral endplate, is one of the most common pathological triggers of acute and chronic low back pain, significantly depreciating an individual's quality of life and instigating huge socioeconomic costs. Novel emerging therapeutic techniques are hence of great interest to both research and clinical communities alike. Exogenous crosslinking, such as Genipin, and platelet-rich plasma therapies have been recently demonstrated encouraging results for the repair and regeneration of degenerated discs, but there remains a knowledge gap regarding the quantitative degree of effectiveness and particular influence on the mechanical properties of the disc. This study aimed to investigate and quantify the material properties of intact (N = 8), trypsin-denatured (N = 8), Genipin-treated (N = 8), and platelet-rich plasma-treated (N = 8) discs in 32 porcine thoracic motion segments. A poroelastic finite element model was used to describe the mechanical properties during different treatments, while a meta-model analytical approach was used in combination with ex vivo experiments to extract the poroelastic material properties. The results revealed that both Genipin and platelet-rich plasma are able to recover the mechanical properties of denatured discs, thereby affording promising therapeutic modalities. However, platelet-rich plasma-treated discs fared slightly, but not significantly, better than Genipin in terms of recovering the glycosaminoglycans content, an essential building block for healthy discs. In addition to investigating these particular degenerative disc disease therapies, this study provides a systematic methodology for quantifying the detailed poroelastic mechanical properties of intervertebral disc.
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Affiliation(s)
- Mohammad Nikkhoo
- 1 Department of Biomedical Engineering, Science and Research Branch, Islamic Azad University, Tehran, Iran
| | - Jaw-Lin Wang
- 2 Institute of Biomedical Engineering, College of Medicine and Engineering, National Taiwan University, Taipei, Taiwan, ROC
| | - Masoud Abdollahi
- 3 Laboratory of Wearable Technologies & Neuromusculoskeletal Research, Department of Mechanical Engineering, Sharif University of Technology, Tehran, Iran
| | - Yu-Chun Hsu
- 2 Institute of Biomedical Engineering, College of Medicine and Engineering, National Taiwan University, Taipei, Taiwan, ROC
| | - Mohamad Parnianpour
- 3 Laboratory of Wearable Technologies & Neuromusculoskeletal Research, Department of Mechanical Engineering, Sharif University of Technology, Tehran, Iran
| | - Kinda Khalaf
- 4 Department of Biomedical Engineering, Khalifa University of Science, Technology and Research, Abu Dhabi, UAE
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Biomechanical Analysis of a Pedicle Screw-Rod System with a Novel Cross-Link Configuration. Asian Spine J 2016; 10:993-999. [PMID: 27994773 PMCID: PMC5165013 DOI: 10.4184/asj.2016.10.6.993] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/01/2016] [Revised: 04/05/2016] [Accepted: 04/08/2016] [Indexed: 11/08/2022] Open
Abstract
Study Design The strength effects of a pedicle screw-rod system supplemented with a novel cross-link configuration were biomechanically evaluated in porcine spines. Purpose To assess the biomechanical differences between a conventional cross-link pedicle screw-rod system versus a novel cross-link instrumentation, and to determine the effect of the cross-links. Overview of Literature Transverse cross-link systems affect torsional rigidity, but are thought to have little impact on the sagittal motion of spinal constructs. We tested the strength effects in pullout and flexion-compression tests of novel cross-link pedicle screw constructs using porcine thoracic and lumbar vertebrae. Methods Five matched thoracic and lumbar vertebral segments from 15 porcine spines were instrumented with 5.0-mm pedicle screws, which were then connected with 6.0-mm rods after partial corpectomy in the middle vertebral body. The forces required for construct failure in pullout and flexion-compression tests were examined in a randomized manner for three different cross-link configurations: un-cross-link control, conventional cross-link, and cross-link passing through the base of the spinous process. Statistical comparisons of strength data were analyzed using Student's t-tests. Results The spinous process group required a significantly greater pullout force for construct failure than the control group (p=0.036). No difference was found between the control and cross-link groups, or the cross-link and spinous process groups in pullout testing. In flexion-compression testing, the spinous processes group required significantly greater forces for construct failure than the control and cross-link groups (p<0.001 and p=0.003, respectively). However, there was no difference between the control and cross-link groups. Conclusions A novel cross-link configuration that features cross-link devices passing through the base of the spinous processes increased the mechanical resistance in pullout and flexion-compression testing compared to un-cross-link constructs. This configuration provided more resistance to middle-column damage under flexion-compression testing than conventional cross-link configuration.
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Balasubramanian S, Peters JR, Robinson LF, Singh A, Kent RW. Thoracic spine morphology of a pseudo-biped animal model (kangaroo) and comparisons with human and quadruped animals. EUROPEAN SPINE JOURNAL : OFFICIAL PUBLICATION OF THE EUROPEAN SPINE SOCIETY, THE EUROPEAN SPINAL DEFORMITY SOCIETY, AND THE EUROPEAN SECTION OF THE CERVICAL SPINE RESEARCH SOCIETY 2016; 25:4140-4154. [PMID: 27704284 DOI: 10.1007/s00586-016-4776-x] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/26/2015] [Revised: 07/22/2016] [Accepted: 09/09/2016] [Indexed: 11/30/2022]
Abstract
PURPOSE Based on the structural anatomy, loading condition and range of motion (ROM), no quadruped animal has been shown to accurately mimic the structure and biomechanical function of the human spine. The objective of this study is to quantify the thoracic vertebrae geometry of the kangaroo, and compare with adult human, pig, sheep, and deer. METHODS The thoracic vertebrae (T1-T12) from whole body CT scans of ten juvenile kangaroos (ages 11-14 months) were digitally reconstructed and geometric dimensions of the vertebral bodies, endplates, pedicles, spinal canal, processes, facets and intervertebral discs were recorded. Similar data available in the literature on the adult human, pig, sheep, and deer were compared to the kangaroo. A non-parametric trend analysis was performed. RESULTS Thoracic vertebral dimensions of the juvenile kangaroo were found to be generally smaller than those of the adult human and quadruped animals. The most significant (p < 0.001) correlations (Rho) found between the human and kangaroo were in vertebrae and endplate dimensions (0.951 ≤ Rho ≤ 0.963), pedicles (0.851 ≤ Rho ≤ 0.951), and inter-facet heights (0.891 ≤ Rho ≤ 0.967). The deer displayed the least similar trends across vertebral levels. CONCLUSIONS Similarities in thoracic spine vertebral geometry, particularly of the vertebrae, pedicles and facets may render the kangaroo a more clinically relevant human surrogate for testing spinal implants. The pseudo-biped kangaroo may also be a more suitable model for the human thoracic spine for simulating spine deformities, based on previously published similarities in biomechanical loading, posture and ROM.
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Affiliation(s)
- Sriram Balasubramanian
- School of Biomedical Engineering, Science and Health Systems, Drexel University, 3141 Chestnut Street, Bossone 718, Philadelphia, PA, 19104, USA.
| | - James R Peters
- School of Biomedical Engineering, Science and Health Systems, Drexel University, 3141 Chestnut Street, Bossone 718, Philadelphia, PA, 19104, USA
| | - Lucy F Robinson
- Department of Epidemiology & Biostatistics, School of Public Health, Drexel University, Nesbitt Hall, 3215 Market Street, Philadelphia, PA, 19104, USA
| | - Anita Singh
- Department of Biomedical Engineering, Widener University, One University Place, Chester, PA, 19013, USA
| | - Richard W Kent
- Mechanical and Aerospace Department, University of Virginia, 122 Engineer's Way, P.O. Box 400746, Charlottesville, VA, 22904-4746, USA
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Zondervan RL, Popovich JM, Radcliffe CJ, Pathak PK, Reeves NP. Sagittal rotational stiffness and damping increase in a porcine lumbar spine with increased or prolonged loading. J Biomech 2016; 49:624-7. [DOI: 10.1016/j.jbiomech.2016.02.002] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/21/2015] [Revised: 01/20/2016] [Accepted: 02/03/2016] [Indexed: 10/22/2022]
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Petit Y, Boisclair D, Parent S, Mac-Thiong JM. Simulation of high energy vertebral fractures on complete porcine specimens. ANNUAL INTERNATIONAL CONFERENCE OF THE IEEE ENGINEERING IN MEDICINE AND BIOLOGY SOCIETY. IEEE ENGINEERING IN MEDICINE AND BIOLOGY SOCIETY. ANNUAL INTERNATIONAL CONFERENCE 2016; 2015:3901-4. [PMID: 26737146 DOI: 10.1109/embc.2015.7319246] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Abstract
This work presents a novel method creating high energy vertebral fractures on complete swine specimens to investigate realistic vertebral fracture mechanisms. An apparatus was developed to maintain a porcine specimen in an upright position and apply a caudal impact simulating a fall. Five mature minipigs were impacted with varying impact magnitude. Computed tomography scans were used to assess the resulting fracture type, fracture level, spinal canal encroachment and fractures of adjacent bony structures. Lumbar fractures were produced on four specimens: three inferior endplate burst fractures (L2) and one superior endplate burst fracture (L5). One trial resulted in a hyperextension fracture between L2 and L3 vertebrae. Spinal canal encroachment was important for three specimens. No fracture was created on the pelvis or hind limbs. The proposed method developed and the resulting swine model of high energy vertebral fractures could be used to instigate novel biomechanical studies, to validate finite element models or to investigate surgical strategies.
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Mehmanparast H, Petit Y, Mac-Thiong JM. Comparison of Pedicle Screw Loosening Mechanisms and the Effect on Fixation Strength. J Biomech Eng 2015; 137:121003. [PMID: 26502116 DOI: 10.1115/1.4031821] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/02/2015] [Indexed: 11/08/2022]
Abstract
Screw loosening is a common complication in spinal fixation using pedicle screws which may lead to loss of correction and revision surgery. The mechanisms of pedicle screw loosening are not well understood. The purpose of this study was to compare the pedicle screw pullout force and stiffness subsequent or not to multidirectional cyclic bending load (toggling). Pedicle screws inserted into porcine lumbar vertebrae underwent toggling in craniocaudal (CC), mediolateral (ML) directions, and no toggling (NT) before pullout. This study suggests that toggling and in particular CC toggling should be included in biomechanical evaluation of pedicle screw fixation strength.
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Affiliation(s)
- Hedayeh Mehmanparast
- Mechanical Engineering Department, École de Technologie Superieure, 1100 Notre-Dame Street, West Montreal, QC H3C 1K3, Canada
- Research Center, Hôpital Sacré-Coeur de Montréal, 5400 Gouin Boulevard, West Montreal, QC H4J 1C5, Canada e-mail:
| | - Yvan Petit
- Mechanical Engineering Department, École de Technologie Superieure, 1100 Notre-Dame Street, West Montreal, QC H3C 1K3, Canada
- Research Center, Hôpital Sacré-Coeur de Montréal, 5400 Gouin Boulevard, West Montreal, QC H4J 1C5, Canada e-mail:
| | - Jean-Marc Mac-Thiong
- Research Center, Hôpital Sacré-Coeur de Montréal, 5400 Gouin Boulevard, West Montreal, QC H4J 1C5, Canada
- Department of Surgery, Université de Montréal, 2900 Éduard-Montpetit Boulevard, Montreal, QC H3T 1C5, Canada e-mail:
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Determination of the mechanical properties of lumbar porcine vertebrae with 2D digital image correlation. J Appl Biomater Funct Mater 2015; 13:e195-200. [PMID: 26350348 DOI: 10.5301/jabfm.5000175] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 04/29/2013] [Indexed: 11/20/2022] Open
Abstract
PURPOSE To evaluate the strain fields and to calculate the modulus of elasticity and Poisson's ratio of trabecular bone of the 6 lumbar vertebrae of the porcine spine by a 2-dimensional digital image correlation (2D DIC). METHODS This study was performed through a 2D DIC technique and the specimens were tested under compression. The resulting images were analyzed numerically by 2D DIC. Then, representative regions of interest were examined. The strain fields were determined and stress-strain curves were obtained. RESULTS The full field measurement of the strain in the lumbar bone spine was evaluated and with this data, the Young's modulus and Poisson's ratio were determined. CONCLUSIONS This research highlights the potential applications of noninvasive acquisition techniques in biomechanical analysis. This is useful in the mechanical characterization of bony structures and in the design of prostheses.
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