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Hedlund J, Ekström L, Thoreson O. Porcine Functional Spine Unit in orthopedic research, a systematic scoping review of the methodology. J Exp Orthop 2022; 9:54. [PMID: 35678892 PMCID: PMC9184692 DOI: 10.1186/s40634-022-00488-6] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/25/2022] [Accepted: 05/16/2022] [Indexed: 11/20/2022] Open
Abstract
Purpose The aim of this study was to conduct a systematic scoping review of previous in vitro spine studies that used pig functional spinal units (FSU) as a model to gain an understanding of how different experimental methods are presented in the literature. Research guidelines are often used to achieve high quality in methods, results, and reports, but no research guidelines are available regarding in vitro biomechanical spinal studies. Methods A systematic scoping review approach and protocol was used for the study with a systematic search in several data bases combined with an extra author search. The articles were examined in multiple stages by two different authors in a blinded manner. Data was extracted from the included articles and inserted into a previously crafted matrix with multiple variables. The data was analyzed to evaluate study methods and quality and included 70 studies. Results The results display that there is a lack of consensus regarding how the material, methods and results are presented. Load type, duration and magnitude were heterogeneous among the studies, but sixty-seven studies (96%) did include compressive load or tension in the testing protocol. Conclusions This study concludes that an improvement of reported data in the present field of research is needed. A protocol, modified from the ARRIVE guidelines, regarding enhanced report-structure, that would enable comparison between studies and improve the method quality is presented in the current study. There is also a clear need for a validated quality-assessment template for experimental animal studies.
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Affiliation(s)
- Jacob Hedlund
- Department of Orthopedics, Institute of Clinical Sciences at Sahlgrenska Academy, University of Gothenburg, Gothenburg, Sweden
| | - Lars Ekström
- Orthopaedic Research Unit, Sahlgrenska University Hospital, Mölndal, Sweden
| | - Olof Thoreson
- Department of Orthopedics, Institute of Clinical Sciences at Sahlgrenska Academy, University of Gothenburg, Gothenburg, Sweden. .,Research and Development Primary Health Care, R&D Centre Gothenburg and Södra Bohuslän, Gothenburg, Sweden.
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Oh J, Jo D, Park K, Kang P, Shin Y. Experimental Rat Model of Bony Defects in the Facet Joint Maintained with Bone Wax for the Study of Spinal Pain. J Pain Res 2022; 15:171-180. [PMID: 35125888 PMCID: PMC8807867 DOI: 10.2147/jpr.s344810] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/16/2021] [Accepted: 01/11/2022] [Indexed: 12/03/2022] Open
Abstract
Purpose Studies using experimental rat models for low back pain due to facet-joint defects are scarce. This study used a novel experimental rat model to determine whether bony defects induced by facetectomy could be maintained by bone wax, thus mimicking spondylolysis, and to analyze the effect of the facetectomy on rat behavior. Patients and Methods Twelve 10-week-old male Wistar rats weighing 300–350 g were divided into group A (n = 6) that underwent unilateral facetectomy of the right L5-6 facet joint and group B (n = 6) that additionally applied water-soluble bone wax at the facetectomy site. The difference in the left and right stride length, detected by the footprint test, and change in the left and right facet joint area were compared before and 4 weeks after the experiment. Results Even though the difference between the left and right stride lengths of groups A and B was not statistically significant, in contrast to group A, group B showed a shorter stride length on the right side (p = 0.22 and 0.46, in group A and group B, respectively). The right facet joint area, where the facetectomy was performed, was significantly smaller in group B 4 weeks after surgery, but not in group A (p = 0.50 and < 0.01, in group A and group B, respectively). Conclusion Based on the results, we concluded that the bony defects, induced by facetectomy at the L5-6 facet joint, were maintained with bone wax. This study will provide an experimental model for bony defects in the facet joint.
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Affiliation(s)
- Jinyoung Oh
- Department of Anesthesiology and Pain Medicine, Kyungpook National University Chilgok Hospital, School of Medicine, Kyungpook National University, Daegu, Republic of Korea
| | - Daehyun Jo
- Jodaehyun Pain Center, Jeonju, Republic of Korea
| | - Kicheol Park
- Clinical Research Institute, Daejeon St. Mary’s Hospital, The Catholic University of Korea, Daejeon, Republic of Korea
| | - Posoon Kang
- Department of Anesthesiology and Pain Medicine, Konynang University Hospital, Daejeon, Republic of Korea
| | - Youngsup Shin
- Department of Anesthesiology and Pain Medicine, Chungnam National University College of Medicine, Daejeon, Republic of Korea
- Correspondence: Youngsup Shin, Department of Anesthesiology and Pain Medicine, Chungnam National University College of Medicine, 282, Munhwa-ro, Junggu, Daejon, 35015, Republic of Korea, Tel +82-42-280-7840, Fax +82-42-280-7968, Email
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Lee NN, Salzer E, Bach FC, Bonilla AF, Cook JL, Gazit Z, Grad S, Ito K, Smith LJ, Vernengo A, Wilke H, Engiles JB, Tryfonidou MA. A comprehensive tool box for large animal studies of intervertebral disc degeneration. JOR Spine 2021; 4:e1162. [PMID: 34337336 PMCID: PMC8313180 DOI: 10.1002/jsp2.1162] [Citation(s) in RCA: 16] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/16/2020] [Revised: 05/25/2021] [Accepted: 05/26/2021] [Indexed: 12/12/2022] Open
Abstract
Preclinical studies involving large animal models aim to recapitulate the clinical situation as much as possible and bridge the gap from benchtop to bedside. To date, studies investigating intervertebral disc (IVD) degeneration and regeneration in large animal models have utilized a wide spectrum of methodologies for outcome evaluation. This paper aims to consolidate available knowledge, expertise, and experience in large animal preclinical models of IVD degeneration to create a comprehensive tool box of anatomical and functional outcomes. Herein, we present a Large Animal IVD Scoring Algorithm based on three scales: macroscopic (gross morphology, imaging, and biomechanics), microscopic (histological, biochemical, and biomolecular analyses), and clinical (neurologic state, mobility, and pain). The proposed algorithm encompasses a stepwise evaluation on all three scales, including spinal pain assessment, and relevant structural and functional components of IVD health and disease. This comprehensive tool box was designed for four commonly used preclinical large animal models (dog, pig, goat, and sheep) in order to facilitate standardization and applicability. Furthermore, it is intended to facilitate comparison across studies while discerning relevant differences between species within the context of outcomes with the goal to enhance veterinary clinical relevance as well. Current major challenges in pre-clinical large animal models for IVD regeneration are highlighted and insights into future directions that may improve the understanding of the underlying pathologies are discussed. As such, the IVD research community can deepen its exploration of the molecular, cellular, structural, and biomechanical changes that occur with IVD degeneration and regeneration, paving the path for clinically relevant therapeutic strategies.
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Affiliation(s)
- Naomi N. Lee
- Thompson Laboratory for Regenerative OrthopaedicsUniversity of MissouriColumbiaMissouriUSA
| | - Elias Salzer
- Orthopaedic Biomechanics, Department of Biomedical EngineeringEindhoven University of TechnologyEindhovenThe Netherlands
| | - Frances C. Bach
- Department of Clinical Sciences, Faculty of Veterinary MedicineUtrecht UniversityUtrechtThe Netherlands
| | - Andres F. Bonilla
- Preclinical Surgical Research Laboratory, Department of Clinical SciencesColorado State UniversityColoradoUSA
| | - James L. Cook
- Thompson Laboratory for Regenerative OrthopaedicsUniversity of MissouriColumbiaMissouriUSA
| | - Zulma Gazit
- Department of SurgeryCedars‐Sinai Medical CenterLos AngelesCaliforniaUSA
| | | | - Keita Ito
- Orthopaedic Biomechanics, Department of Biomedical EngineeringEindhoven University of TechnologyEindhovenThe Netherlands
| | - Lachlan J. Smith
- Departments of Neurosurgery and Orthopaedic SurgeryUniversity of PennsylvaniaPhiladelphiaPennsylvaniaUSA
| | - Andrea Vernengo
- AO Research Institute DavosDavosSwitzerland
- Department of Chemical EngineeringRowan UniversityGlassboroNew JerseyUSA
| | - Hans‐Joachim Wilke
- Institute of Orthopaedic Research and BiomechanicsUniversity Hospital UlmUlmGermany
| | - Julie B. Engiles
- Department of Pathobiology, New Bolton Center, School of Veterinary MedicineUniversity of PennsylvaniaKennett SquarePennsylvaniaUSA
| | - Marianna A. Tryfonidou
- Department of Clinical Sciences, Faculty of Veterinary MedicineUtrecht UniversityUtrechtThe Netherlands
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Bhunia BK, Mandal BB. Exploring Gelation and Physicochemical Behavior of in Situ Bioresponsive Silk Hydrogels for Disc Degeneration Therapy. ACS Biomater Sci Eng 2018; 5:870-886. [DOI: 10.1021/acsbiomaterials.8b01099] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Bibhas K. Bhunia
- Biomaterial and Tissue Engineering Laboratory, Department of Biosciences and Bioengineering, Indian Institute of Technology Guwahati, Guwahati 781 039, India
| | - Biman B. Mandal
- Biomaterial and Tissue Engineering Laboratory, Department of Biosciences and Bioengineering, Indian Institute of Technology Guwahati, Guwahati 781 039, India
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Sterba M, Arnoux PJ, Labelle H, Warner WC, Aubin CÉ. Biomechanical analysis of spino-pelvic postural configurations in spondylolysis subjected to various sport-related dynamic loading conditions. 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 2018; 27:2044-2052. [PMID: 29926211 DOI: 10.1007/s00586-018-5667-0] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/02/2017] [Revised: 06/13/2018] [Accepted: 06/13/2018] [Indexed: 12/17/2022]
Abstract
PURPOSE To study the risks of spondylolysis due to extrinsic loading conditions related to sports activities and intrinsic spino-pelvic postural parameters [pelvic incidence (PI) and sacral slope (SS)]. METHODS A comprehensive osseo-disco-ligamentous L4-S1 finite element model was built for three cases with spondylolysis representing three different spino-pelvic angular configurations (SS = 32°, 47°, 59° and PI = 49°, 58°, 72°, respectively). After simulating the standing posture, 16 dynamic loading conditions were computationally tested for each configuration by combining four sport-related loads (compression, sagittal and lateral bending and axial torque). For each simulation, the Von Mises stress, L5-S1 facet contact force and resultant internal loads at the sacral endplate were computed. Significant effects were determined with an ANOVA. RESULTS The maximal stress and volume of cancellous bone in the pars with stress higher than 75% of the ultimate stress were higher with 900 N simulated compression (2.2 MPa and 145 mm3) compared to only the body weight (1.36 MPa and 20.9 mm3) (p < 0.001). Combined compression with 10 Nm of flexion and an axial torque of 6 Nm generated the highest stress conditions (up to 2.7 MPa), and L5-S1 facet contact force (up to 430 N). The maximal stress was on average 17% higher for the case with the highest SS compared to the one with lowest SS for the 16 tested conditions (p = 0.0028). CONCLUSIONS Combined flexion and axial rotation with compression generated the highest stress conditions related to risks of spondylolysis. The stress conditions intensify in patients with higher PI and SS. These slides can be retrieved under Electronic Supplementary Material.
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Affiliation(s)
- Manon Sterba
- Department of Mechanical Engineering, Polytechnique Montreal, Montreal, QC, Canada.,Laboratoire de Biomécanique Appliquée, Aix-Marseille Université, IFSTTAR, LBA UMR T24, Marseille, France.,iLab-Spine (International Laboratory - Spine Imaging and Biomechanics), Montreal, Canada.,iLab-Spine (International Laboratory - Spine Imaging and Biomechanics), Marseille, France.,Sainte-Justine University Hospital Center, Montreal, QC, Canada
| | - Pierre-Jean Arnoux
- Laboratoire de Biomécanique Appliquée, Aix-Marseille Université, IFSTTAR, LBA UMR T24, Marseille, France.,iLab-Spine (International Laboratory - Spine Imaging and Biomechanics), Marseille, France
| | - Hubert Labelle
- Sainte-Justine University Hospital Center, Montreal, QC, Canada
| | | | - Carl-Éric Aubin
- Department of Mechanical Engineering, Polytechnique Montreal, Montreal, QC, Canada. .,iLab-Spine (International Laboratory - Spine Imaging and Biomechanics), Montreal, Canada. .,Sainte-Justine University Hospital Center, Montreal, QC, Canada.
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Howarth SJ, Karakolis T, Callaghan JP. A finite element evaluation of the moment arm hypothesis for altered vertebral shear failure force. Comput Methods Biomech Biomed Engin 2015; 18:545-55. [DOI: 10.1080/10255842.2013.820717] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
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Biomechanical stability of lateral interbody implants and supplemental fixation in a cadaveric degenerative spondylolisthesis model. Spine (Phila Pa 1976) 2014; 39:E1138-46. [PMID: 24979274 DOI: 10.1097/brs.0000000000000485] [Citation(s) in RCA: 26] [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
STUDY DESIGN In vitro cadaveric biomechanical study of lateral interbody cages and supplemental fixation in a degenerative spondylolisthesis (DS) model. OBJECTIVE To investigate changes in shear and flexion-extension stability of lateral interbody fusion constructs. SUMMARY OF BACKGROUND DATA Instability associated with DS may increase postoperative treatment complications. Several groups have investigated DS in cadaveric spines. Extreme lateral interbody fusion (XLIF) cages with supplemental fixation have not previously been examined using a DS model. METHODS Seven human cadaveric L4-L5 motion segments were evaluated using flexion-extension moments to ±7.5 N·m and anterior-posterior (A-P) shear loading of 150 N with a static axial compressive load of 300 N. Conditions were: (1) intact segment, (2) DS simulation with facet resection and lateral discectomy, (3) standalone XLIF cage, (4) XLIF cage with (1) lateral plate, (2) lateral plate and unilateral pedicle screws contralateral to the plate (PS), (3) unilateral PS, (4) bilateral PS, (5) spinous process plate, and (6) lateral plate and spinous process plate. Flexion-extension range of motion (ROM) data were compared between conditions and with results from a previous study without DS simulation. A-P shear displacements were compared between conditions. RESULTS Flexion-extension ROM after DS destabilization increased significantly by 181% of intact ROM. With the XLIF cage alone, ROM decreased to 77% of intact. All conditions were less stable than corresponding conditions with intact posterior elements except those including the spinous process plate. Under shear loading, A-P displacement with the XLIF cage alone increased by 2.2 times intact. Bilateral PS provided the largest reduction of A-P displacement, whereas the spinous process plate alone provided the least. CONCLUSION This is the first in vitro shear load testing of XLIF cages with supplemental fixation in a cadaveric DS model. The variability in sagittal plane construct stability, including significantly increased flexion-extension ROM found with most fixation conditions including bilateral PS may explain some clinical treatment complications in DS with residual instability. LEVEL OF EVIDENCE N/A.
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Fleischer GD, Hart D, Ferrara LA, Freeman AL, Avidano EE. Biomechanical effect of transforaminal lumbar interbody fusion and axial interbody threaded rod on range of motion and S1 screw loading in a destabilized L5-S1 spondylolisthesis model. Spine (Phila Pa 1976) 2014; 39:E82-8. [PMID: 24150429 DOI: 10.1097/brs.0000000000000077] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/01/2023]
Abstract
STUDY DESIGN A cadaveric lumbosacral spondylolytic spondylolisthesis model was used to evaluate the biomechanical function of 2 different interbody spacers. OBJECTIVE To analyze and compare the reduction in pedicle screw strain and spine range of motion (ROM) between transforaminal lumbar interbody fusion (TLIF) and an axial interbody threaded rod (AxialITR) in a destabilized L5-S1 spondylolisthesis model. SUMMARY OF BACKGROUND DATA Symptomatic spondylolytic spondylolisthesis is often treated with posterior instrumented fusion augmented by a variety of different interbody devices. Interbody spacers rely primarily on posterior instrumentation to stabilize the spine during fusion, but there may be advantages to the more rigid support offered by an anterior threaded rod. METHODS Pure-moment flexibility testing was performed on L3-S1 cadaveric specimens in 4 conditions: (1) Intact, (2) L5-S1 pedicle screws (PS) + L5-S1 disc destabilization (DDS), (3) TLIF at L5-S1 + PS + DDS, and (4) AxialITR at L5-S1 + PS + DDS. Specimens were destabilized by performing a complete denucleation at L5-S1 and sectioning two-thirds of the annulus' width from anterior to posterior. The S1 PSs were instrumented with strain gauges to measure screw-bending moments and ROM was quantified with a noncontact camera system. RESULTS S1 screw strains were highest with PS but were significantly reduced by 73% in flexion and 31% in extension with TLIF (P ≤ 0.004). AxialITR significantly reduced strain by 78% in flexion and 81% in extension (P ≤ 0.001). ROM was smallest with AxialITR in each test direction at 1.7 ± 1.8° in flexion-extension, 1.6 ± 0.9° in lateral bending and 1.3 ± 0.8° in torsion. CONCLUSION This study demonstrated that ROM and S1 screw-bending moments were reduced with the use of AxialITR and TLIF. Although the TLIF and AxialITR both reduced strains and motion, the AxialITR provided a significant reduction in extension strain when compared with TLIF. LEVEL OF EVIDENCE N/A.
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Affiliation(s)
- Gary D Fleischer
- *Southern New Hampshire Medical Center, Nashua, NH †Cleveland Clinic, Cleveland, OH ‡OrthoKinetic Technologies, Southport, NC §Excelen Center for Bone and Joint Research, Minneapolis, MN; and ¶TranS1, Wilmington, NC
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Howarth SJ, Giangregorio LM, Callaghan JP. Development of an equation for calculating vertebral shear failure tolerance without destructive mechanical testing using iterative linear regression. Med Eng Phys 2013; 35:1212-20. [PMID: 23337706 DOI: 10.1016/j.medengphy.2012.12.009] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/31/2011] [Revised: 11/30/2012] [Accepted: 12/26/2012] [Indexed: 10/27/2022]
Abstract
Equations used to determine vertebral failure tolerances without the need for destructive testing are useful for scaling applied sub-maximal forces during in vitro repetitive loading studies. However, existing equations that use vertebral bone density and morphology for calculating compressive failure tolerance are unsuitable for calculating vertebral shear failure tolerance since the primary site of failure is the pars interarticularis and not the vertebral body. Therefore, this investigation developed new equations for non-destructively determining vertebral shear failure tolerance from morphological and/or bone density measures. Shear failure was induced in 40 porcine cervical vertebral joints (20 C3-C4 and 20 C5-C6) by applying a constant posterior displacement to the caudal vertebra at 0.15 mm/s. Prior to destructive testing, morphology and bone density of the posterior elements were made with digital calipers, X-rays, and peripheral quantitative computed tomography. Iterative linear regression identified mathematical relationships between shear failure tolerance, and morphological and bone density measurements. Along with vertebral level, pars interarticularis length and lamina height from the cranial vertebra, and inferior facet height from the caudal vertebra collectively explained 61.8% of shear failure tolerance variance. Accuracy for this relationship, estimated using the same group of specimens, was 211.9 N or 9.8% of the measured shear failure tolerance.
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Affiliation(s)
- Samuel J Howarth
- Department of Graduate Education and Research Programs, Canadian Memorial Chiropractic College, Toronto, Ontario, Canada
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Abstract
STUDY DESIGN A biomechanical human cadaveric study. OBJECTIVE To create a biomechanical model of low-grade degenerative lumbar spondylolisthesis (DLS), defined by anterior listhesis, for future testing of spinal instrumentation. SUMMARY OF BACKGROUND DATA Current spinal implants are used to treat a multitude of conditions that range from herniated discs to degenerative diseases. The optimal stiffness of these instrumentation systems for each specific spinal condition is unknown. Ex vivo models representing degenerative spinal conditions are scarce in the literature. A model of DLS for implant testing will enhance our understanding of implant-spine behavior for specific populations of patients. METHODS Four incremental surgical destabilizations were performed on 8 lumbar functional spinal units. The facet complex and intervertebral disc were targeted to represent the tissue changes associated with DLS. After each destabilization, the specimen was tested with: (1) applied shear force (-50 to 250 N) with a constant axial compression force (300 N) and (2) applied pure moments in flexion-extension, lateral bending and axial rotation (±5 Nm). Relative motion between the 2 vertebrae was tracked with a motion capture system. The effect of specimen condition on intervertebral motion was assessed for shear and flexibility testing. RESULTS Shear translation increased, specimen stiffness decreased and range of motion increased with specimen destabilization (P < 0.0002). A mean anterior translation of 3.1 mm (SD 1.1 mm) was achieved only after destabilization of both the facet complex and disc. Of the 5 specimen conditions, 3 were required to achieve grade 1 DLS: (1) intact, (3) a 4-mm facet gap, and (5) a combined nucleus and annulus injury. CONCLUSION Destabilization of both the facet complex and disc was required to achieve anterior listhesis of 3.1 mm consistent with a grade 1 DLS under an applied shear force of 250 N. Sufficient listhesis was measured without radical specimen resection. Important anatomical structures for supporting spinal instrumentation were preserved such that this model can be used in future to characterize behavior of novel instrumentation prior to clinical trials.
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Howarth SJ, Callaghan JP. Towards establishing an occupational threshold for cumulative shear force in the vertebral joint - an in vitro evaluation of a risk factor for spondylolytic fractures using porcine specimens. Clin Biomech (Bristol, Avon) 2013; 28:246-54. [PMID: 23360894 DOI: 10.1016/j.clinbiomech.2013.01.003] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/24/2012] [Revised: 12/11/2012] [Accepted: 01/02/2013] [Indexed: 02/07/2023]
Abstract
BACKGROUND Injury models for spondylolytic fracture of the pars interarticularis have long considered repetitive shear loading as a risk factor without quantifying the relationship between shear force magnitude and fatigue life. This investigation sought to quantify the relationship using a basic in vitro approach. METHODS Thirty-two (16 C3-C4, 16 C5-C6) porcine cervical specimens were exposed to repetitive shear loading to 20%, 40%, 60%, or 80% of their calculated ultimate anterior shear failure tolerance. Shear force was cyclically applied at 1Hz for 21,600cycles or until bone failure was detected. Cumulative shear force and the number of cycles sustained until failure were calculated. Failure patterns were also documented. FINDINGS Cumulative shear and the number of cycles sustained prior to failure demonstrated a strong non-linearly decreasing relationship with increased force magnitude. In particular, sustained cumulative shear by the 40% group was 2.52 and 2.63MN∗s higher than for the 60% and 80% groups (P<0.0001). Despite undergoing an average of 230 more loading cycles, cumulative shear force sustained by the 60% group was not statistically different from the 80% group. Bilateral fractures of the cranial vertebra's pars interarticularis were most common, but less consistent at higher force magnitudes. INTERPRETATION Our investigation suggested that pars interarticularis damage may begin non-linearly accumulating with shear forces between 20% and 40% of failure tolerance (approximately 430 to 860N). Models of pars interarticularis injury and estimates of cumulative shear exposure may be enhanced from a tissue-based weighting method for low-back shear.
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Affiliation(s)
- Samuel J Howarth
- Canadian Memorial Chiropractic College, Toronto, Ontario, Canada
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Gallagher S, Marras WS. Tolerance of the lumbar spine to shear: a review and recommended exposure limits. Clin Biomech (Bristol, Avon) 2012; 27:973-8. [PMID: 22967740 DOI: 10.1016/j.clinbiomech.2012.08.009] [Citation(s) in RCA: 95] [Impact Index Per Article: 7.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/13/2012] [Revised: 08/22/2012] [Accepted: 08/24/2012] [Indexed: 02/07/2023]
Abstract
BACKGROUND The lumbar spine may experience significant shear forces during occupational tasks due to the force of gravity acting on the upper body when bending the trunk forward, or when performing tasks involving pushing or pulling. Shear force limits of 1000 N and 500 N have been recommended by previous authors for maximum permissible limit and action limit, respectively. METHODS The present paper reviews literature in terms of shear tolerance (ultimate shear stress and fatigue life in shear stress) of the lumbar spine and develops recommended limits based on results of studies examining shear loading of human motion segments. Weibull analysis was used to assess fatigue failure data to estimate distributions of failure at different percentages of ultimate shear stress. FINDINGS Based on Weibull analysis of fatigue failure data from the best available data, a 1000 N shear limit would appear acceptable for occasional exposure to shear loading (≤ 100 loadings/day); however, a 700 N limit would appear appropriate for repetitive shear loading (100-1000 loadings/day) for most workers. INTERPRETATION Results of the current analysis support the 1000 N limit for shear stress, but for a rather limited number of cycles (<100 per day). Due to the logarithmic nature of the fatigue failure curve, a 700 N shear limit would appear to be acceptable for frequent shear loadings (100-1000 per day). This value is slightly higher than the action limit of 500 N previously recommended.
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Affiliation(s)
- Sean Gallagher
- Auburn University, Department of Industrial and Systems Engineering, Auburn University, AL, USA.
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Abstract
Back pain in the young athlete is a common complaint and often perceived as a challenging problem. A well-directed approach will usually provide the practitioner with a higher comfort zone. The etiology of back pain in the pediatric and adolescent population is different from that of the adult population due to the presence of open physes and increased linear growth velocity. In addition, the frequency and intensity of sports participation in children continues to increase, leading to more overuse injuries. This review article will discuss the anatomy and physiology of the spine and pelvis, as well as focus on the chronic and overuse causes of back pain in the young athlete.
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Affiliation(s)
- Warren K Young
- Department of Orthopaedic Surgery, New York University Hospital for Joint Disease, New York, NY, USA.
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Bisschop A, Mullender MG, Kingma I, Jiya TU, van der Veen AJ, Roos JC, van Dieën JH, van Royen BJ. The impact of bone mineral density and disc degeneration on shear strength and stiffness of the lumbar spine following laminectomy. 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 2011; 21:530-6. [PMID: 21863461 PMCID: PMC3296849 DOI: 10.1007/s00586-011-1968-2] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 02/25/2011] [Revised: 06/01/2011] [Accepted: 07/31/2011] [Indexed: 11/25/2022]
Abstract
Purpose Laminectomy is a standard surgical procedure for elderly patients with symptomatic degenerative lumbar stenosis. The procedure aims at decompression of the affected nerves, but it also causes a reduction of spinal shear strength and shear stiffness. The magnitude of this reduction and the influence of bone mineral density (BMD) and disc degeneration are unknown. We studied the influence of laminectomy, BMD, and disc degeneration on shear force to failure (SFF) and shear stiffness (SS). Methods Ten human cadaveric lumbar spines were obtained (mean age 72.1 years, range 53–89 years). Laminectomy was performed either on L2 or L4, equally divided within the group of ten spines. BMD was assessed by dual X-ray absorptiometry (DXA). Low BMD was defined as a BMD value below the median. Intervertebral discs were assessed for degeneration by MRI (Pfirrmann) and scaled in mild and severe degeneration groups. Motion segments L2–L3 and L4–L5 were isolated from each spine. SFF and SS were measured, while loading simultaneously with 1,600 N axial compression. Results Low BMD had a significant negative effect on SFF. In addition, a significant interaction between low BMD and laminectomy was found. In the high BMD group, SFF was 2,482 N (range 1,678–3,284) and decreased to 1,371 N (range 940–1,886) after laminectomy. In the low BMD group, SFF was 1,339 N (range 909–1,628) and decreased to 761 N (range 561–1,221). Disc degeneration did not affect SFF, nor did it interact with laminectomy. Neither low BMD nor the interaction of low BMD and laminectomy did affect SS. Degeneration and its interaction with laminectomy did not significantly affect SS. Conclusions In conclusion, low BMD significantly decreased SFF before and after lumbar laminectomy. Therefore, DXA assessment may be an important asset to preoperative screening. Lumbar disc degeneration did not affect shear properties of lumbar segments before or after laminectomy.
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Affiliation(s)
- Arno Bisschop
- Department of Orthopedic Surgery, Research Institute MOVE, VU University Medical Center, De Boelelaan 1117, P.O. Box 7057, 1081 HV, Amsterdam, The Netherlands
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van Solinge GB, van der Veen AJ, van Dieën JH, Kingma I, van Royen BJ. Anterior shear strength of the porcine lumbar spine after laminectomy and partial facetectomy. 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 2010; 19:2130-6. [PMID: 20582709 DOI: 10.1007/s00586-010-1492-9] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/11/2010] [Revised: 05/02/2010] [Accepted: 06/11/2010] [Indexed: 01/24/2023]
Abstract
Degenerative lumbar spinal stenosis is the most common reason for lumbar surgery in patients in the age of 65 years and older. The standard surgical management is decompression of the spinal canal by laminectomy and partial facetectomy. The effect of this procedure on the shear strength of the spine has not yet been investigated in vitro. In the present study we determined the ultimate shear force to failure, the displacement and the shear stiffness after performing a laminectomy and a partial facetectomy. Eight lumbar spines of domestic pigs (7 months old) were sectioned to obtain eight L2-L3 and eight L4-L5 motion segments. All segments were loaded with a compression force of 1,600 N. In half of the 16 motion segments a laminectomy and a 50% partial facetectomy were applied. The median ultimate shear force to failure with laminectomy and partial facetectomy was 1,645 N (range 1,066-1,985) which was significantly smaller (p = 0.012) than the ultimate shear force to failure of the control segments (median 2,113, range 1,338-2,659). The median shear stiffness was 197.4 N/mm (range 119.2-216.7) with laminectomy and partial facetectomy which was significantly (p = 0.036) smaller than the stiffness of the control specimens (median 216.5, 188.1-250.2). It was concluded that laminectomy and partial facetectomy resulted in 22% reduction in ultimate shear force to failure and 9% reduction in shear stiffness. Although relatively small, these effects may explain why patients have an increased risk of sustaining shear force related vertebral fractures after spinal decompression surgery.
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Affiliation(s)
- Guido B van Solinge
- Department of Orthopedic Surgery, VU University Medical Center, Amsterdam, The Netherlands
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