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Yang Y, Liao F, Xing X, Liao N, Wang D, Yin X, Liu Y, Guo J, Li L, Wang H, Li C, Zheng Y. The reduced cortical bone density in vertebral bodies: risk for osteoporotic fractures? Insights from CT analysis. J Orthop Surg Res 2024; 19:486. [PMID: 39152470 PMCID: PMC11329995 DOI: 10.1186/s13018-024-04896-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/08/2024] [Accepted: 07/03/2024] [Indexed: 08/19/2024] Open
Abstract
BACKGROUND There is a corresponding increase in the prevalence of osteoporosis and related fractures with the aging population on the rise. Furthermore, osteoporotic vertebral compression fractures (OVCF) may contribute to higher patient mortality rates. It is essential to conduct research on risk factors for OVCF and provide a theoretical basis for preventing such fractures. METHODS We retrospectively recruited patients who had spine CT for OVCF or back pain. Demographic and CT data were collected. Quantitative computed tomography (QCT) software analyzed the CT data, using subcutaneous fat and paraspinal muscles as reference standards for BMD processing. BMD of cortical and cancellous bones in each patient's vertebral body was determined. RESULTS In this study, 144 patients were divided into non-OVCF (96) and OVCF (48) groups. Non-OVCF patients had higher cortical BMD of 382.5 ± 52.4 to 444.6 ± 70.1 mg/cm3, with T12 having the lowest BMD (p < 0.001, T12 vs. L2). Cancellous BMD ranged from 128.5 ± 58.4 to 140.9 ± 58.9 mg/cm3, with L3 having the lowest BMD. OVCF patients had lower cortical BMD of 365.0 ± 78.9 to 429.3 ± 156.7 mg/cm3, with a further decrease in T12 BMD. Cancellous BMD ranged from 71.68 ± 52.07 to 123.9 ± 126.2 mg/cm3, with L3 still having the lowest BMD. Fractured vertebrae in OVCF patients (T12, L1, and L2) had lower cortical bone density compared to their corresponding vertebrae without fractures (p < 0.05). CONCLUSIONS T12 had the lowest cortical BMD and L3 had the lowest cancellous BMD in OVCF patients, with T12 also having the highest incidence of osteoporotic fractures. These findings suggest that reduction in cortical BMD has a greater impact on OVCF than reduction in cancellous BMD, along with biomechanical factors.
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Affiliation(s)
- Yong Yang
- Department of Orthopaedics, Fourth Medical Center of PLA General Hospital, Beijing, PR China
- National Clinical Research Center for Orthopedics, Sports Medicine and Rehabilitation, Beijing, 10048, PR China
- Department of Orthopedics, General Hospital of Western Theater Command, Rongdu Avenue No. 270, Chengdu, 610083, PR China
| | - Feng Liao
- Department of Orthopaedics, Sichuan Provincial People's Hospital, University of Electronic Science and Technology of China, Chengdu, 610072, PR China
| | - Xingbo Xing
- Department of Radiology, Fourth Medical Center of PLA General Hospital, Beijing, 10048, PR China
| | - Nianxi Liao
- Yizhun medical AI Co.Ltd, No.7, Zhichun road, Haidian district, Beijing, 100088, PR China
| | - Dawei Wang
- Department of Orthopaedics, Fourth Medical Center of PLA General Hospital, Beijing, PR China
- National Clinical Research Center for Orthopedics, Sports Medicine and Rehabilitation, Beijing, 10048, PR China
| | - Xin Yin
- Department of Orthopaedics, Fourth Medical Center of PLA General Hospital, Beijing, PR China
| | - Yihao Liu
- Department of Orthopaedics, Fourth Medical Center of PLA General Hospital, Beijing, PR China
| | - Jidong Guo
- Department of Orthopaedics, Fourth Medical Center of PLA General Hospital, Beijing, PR China
- National Clinical Research Center for Orthopedics, Sports Medicine and Rehabilitation, Beijing, 10048, PR China
| | - Li Li
- Department of Orthopaedics, Fourth Medical Center of PLA General Hospital, Beijing, PR China
- National Clinical Research Center for Orthopedics, Sports Medicine and Rehabilitation, Beijing, 10048, PR China
| | - Huadong Wang
- Department of Orthopaedics, Fourth Medical Center of PLA General Hospital, Beijing, PR China.
- National Clinical Research Center for Orthopedics, Sports Medicine and Rehabilitation, Beijing, 10048, PR China.
| | - Chunyan Li
- Department of Clinical Laboratory, Beijing Jishuitan Hospital, Xicheng District, Beijing, 100035, PR China.
| | - Yang Zheng
- Department of Orthopaedics, Fourth Medical Center of PLA General Hospital, Beijing, PR China.
- National Clinical Research Center for Orthopedics, Sports Medicine and Rehabilitation, Beijing, 10048, PR China.
- Department of Orthopedics, General Hospital of Western Theater Command, Rongdu Avenue No. 270, Chengdu, 610083, PR China.
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Avci O, Röhrle O. Determining a musculoskeletal system's pre-stretched state using continuum-mechanical forward modelling and joint range optimization. Biomech Model Mechanobiol 2024; 23:1031-1053. [PMID: 38619712 PMCID: PMC11101507 DOI: 10.1007/s10237-024-01821-x] [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: 08/03/2023] [Accepted: 01/04/2024] [Indexed: 04/16/2024]
Abstract
The subject-specific range of motion (RoM) of a musculoskeletal joint system is balanced by pre-tension levels of individual muscles, which affects their contraction capability. Such an inherent pre-tension or pre-stretch of muscles is not measureable with in vivo experiments. Using a 3D continuum mechanical forward simulation approach for motion analysis of the musculoskeletal system of the forearm with 3 flexor and 2 extensor muscles, we developed an optimization process to determine the muscle fibre pre-stretches for an initial arm position, which is given human dataset. We used RoM values of a healthy person to balance the motion in extension and flexion. The performed sensitivity study shows that the fibre pre-stretches of the m. brachialis, m. biceps brachii and m. triceps brachii with 91 % dominate the objective flexion ratio, while m. brachiradialis and m. anconeus amount 7.8 % and 1.2 % . Within the multi-dimensional space of the surrogate model, 3D sub-spaces of primary variables, namely the dominant muscles and the global objective, flexion ratio, exhibit a path of optimal solutions. Within this optimal path, the muscle fibre pre-stretch of two flexors demonstrate a negative correlation, while, in contrast, the primary extensor, m. triceps brachii correlates positively to each of the flexors. Comparing the global optimum with four other designs along the optimal path, we saw large deviations, e.g., up to 15∘ in motion and up to 40% in muscle force. This underlines the importance of accurate determination of fibre pre-stretch in muscles, especially, their role in pathological muscular disorders and surgical applications such as free muscle or tendon transfer.
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Affiliation(s)
- Okan Avci
- Fraunhofer Institute for Manufacturing Engineering and Automation IPA, Nobelstr. 12, 70569, Stuttgart, Germany.
| | - Oliver Röhrle
- Institute of Modelling and Simulation for Biomechanical Systems and Cluster of Excellence for Simulation Technology, University of Stuttgart, Pfaffenwaldring 5a, 70569, Stuttgart, Germany
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Hammer M, Wenzel T, Santin G, Meszaros-Beller L, Little JP, Haasdonk B, Schmitt S. A new method to design energy-conserving surrogate models for the coupled, nonlinear responses of intervertebral discs. Biomech Model Mechanobiol 2024; 23:757-780. [PMID: 38244146 PMCID: PMC11101520 DOI: 10.1007/s10237-023-01804-4] [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: 06/16/2023] [Accepted: 12/06/2023] [Indexed: 01/22/2024]
Abstract
The aim of this study was to design physics-preserving and precise surrogate models of the nonlinear elastic behaviour of an intervertebral disc (IVD). Based on artificial force-displacement data sets from detailed finite element (FE) disc models, we used greedy kernel and polynomial approximations of second, third and fourth order to train surrogate models for the scalar force-torque -potential. Doing so, the resulting models of the elastic IVD responses ensured the conservation of mechanical energy through their structure. At the same time, they were capable of predicting disc forces in a physiological range of motion and for the coupling of all six degrees of freedom of an intervertebral joint. The performance of all surrogate models for a subject-specific L4 | 5 disc geometry was evaluated both on training and test data obtained from uncoupled (one-dimensional), weakly coupled (two-dimensional), and random movement trajectories in the entire six-dimensional (6d) physiological displacement range, as well as on synthetic kinematic data. We observed highest precisions for the kernel surrogate followed by the fourth-order polynomial model. Both clearly outperformed the second-order polynomial model which is equivalent to the commonly used stiffness matrix in neuro-musculoskeletal simulations. Hence, the proposed model architectures have the potential to improve the accuracy and, therewith, validity of load predictions in neuro-musculoskeletal spine models.
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Affiliation(s)
- Maria Hammer
- Institute for Modelling and Simulation of Biomechanical Systems, University of Stuttgart, Stuttgart, Germany.
- Stuttgart Center for Simulation Science (SC SimTech), University of Stuttgart, Stuttgart, Germany.
| | - Tizian Wenzel
- Stuttgart Center for Simulation Science (SC SimTech), University of Stuttgart, Stuttgart, Germany
- Institute for Applied Analysis and Numerical Simulation, University of Stuttgart, Stuttgart, Germany
| | - Gabriele Santin
- Digital Society Center, Fondazione Bruno Kessler, Trento, Italy
| | - Laura Meszaros-Beller
- Institute for Modelling and Simulation of Biomechanical Systems, University of Stuttgart, Stuttgart, Germany
- Biomechanics and Spine Research Group, School of Mechanical, Medical and Process Engineering, Queensland University of Technology, Brisbane, Australia
| | - Judith Paige Little
- Biomechanics and Spine Research Group, School of Mechanical, Medical and Process Engineering, Queensland University of Technology, Brisbane, Australia
| | - Bernard Haasdonk
- Stuttgart Center for Simulation Science (SC SimTech), University of Stuttgart, Stuttgart, Germany
- Institute for Applied Analysis and Numerical Simulation, University of Stuttgart, Stuttgart, Germany
| | - Syn Schmitt
- Institute for Modelling and Simulation of Biomechanical Systems, University of Stuttgart, Stuttgart, Germany.
- Stuttgart Center for Simulation Science (SC SimTech), University of Stuttgart, Stuttgart, Germany.
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4
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Kian-Bostanabad S, Azghani M, Parnianpour M. Evaluation of the lumbar and abdominal muscles behavior in different sagittal plane angles during maximum voluntary isometric extension. Proc Inst Mech Eng H 2024; 238:301-312. [PMID: 38229471 DOI: 10.1177/09544119231221896] [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] [Indexed: 01/18/2024]
Abstract
Physical positions and lumbar movements are directly related to lumbar disorders. It is known that the sagittal plane angle affects the person's ability to apply extension torque. However, there is no consensus on whether or not muscle activity and co-contractions change at these angles. This paper aimed to investigate the abdominal and lumbar muscles' behavior at different sagittal plane angles during maximum voluntary isometric extension (MVIE). We have evaluated our findings with the aid of a computational biomechanical model. Fourteen healthy males participated. A total of 16 muscles EMG were recorded during the lumbar MVIE on the Sharif Lumbar Isometric Strength Tester device in 5°, 15°, 30°, and 45° flexion. The torque and muscle activity changes and all co-contraction indexes (CCI) between 120 possible muscle pairs were calculated. Finally, the experimental test conditions were modeled in the AnyBody software, and the MVIE torque, muscle activity, and all CCIs were calculated. Also, muscle torque lever arms were calculated at different angles. Results show that MVIE at four angles is 137.94 ± 36.08, 148.63 ± 47.96, 168.09 ± 50.48, and 171.44 ± 53.95 N · m, respectively. Muscle activity and CCI are similar at all angles. The AnyBody model gives similar findings. Muscles torque lever arms change with angle. In conclusion, to determine the safety mode of lifting in the sagittal plane, it seems that the torque differences are due to changes in the geometrical muscle parameters (including the torque lever arm). Despite the almost constant muscular effort, subjects in the 30°-45° bending positions can apply more MVIE.
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Affiliation(s)
- Sharareh Kian-Bostanabad
- Department of Biomechanical Engineering, Faculty of Biomedical Engineering, Sahand University of Technology, Tabriz, Iran
| | - Mahmoodreza Azghani
- Department of Biomechanical Engineering, Faculty of Biomedical Engineering, Sahand University of Technology, Tabriz, Iran
| | - Mohammad Parnianpour
- Department of Mechanical Engineering, Sharif University of Technology, Tehran, Iran
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Chacon PFS, Hammer M, Wochner I, Walter JR, Schmitt S. A physiologically enhanced muscle spindle model: using a Hill-type model for extrafusal fibers as template for intrafusal fibers. Comput Methods Biomech Biomed Engin 2023:1-20. [PMID: 38126259 DOI: 10.1080/10255842.2023.2293652] [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: 09/19/2023] [Accepted: 12/05/2023] [Indexed: 12/23/2023]
Abstract
The muscle spindle is an essential proprioceptor, significantly involved in sensing limb position and movement. Although biological spindle models exist for years, the gold-standard for motor control in biomechanics are still sensors built of homogenized spindle output models due to their simpler combination with neuro-musculoskeletal models. Aiming to improve biomechanical simulations, this work establishes a more physiological model of the muscle spindle, aligned to the advantage of easy integration into large-scale musculoskeletal models. We implemented four variations of a spindle model in Matlab/Simulink®: the Mileusnic et al. (2006) model, Mileusnic model without mass, our enhanced Hill-type model, and our enhanced Hill-type model with parallel damping element (PDE). Different stretches in the intrafusal fibers were simulated in all model variations following the spindle afferent recorded in previous experiments in feline soleus muscle. Additionally, the enhanced Hill-type models had their parameters extensively optimized to match the experimental conditions, and the resulting model was validated against data from rats' triceps surae muscle. As result, the Mileusnic models present a better overall performance generating the afferent firings compared to the common data evaluated. However, the enhanced Hill-type model with PDE exhibits a more stable performance than the original Mileusnic model, at the same time that presents a well-tuned Hill-type model as muscle spindle fibers, and also accounts for real sarcomere force-length and force-velocity aspects. Finally, our activation dynamics is similar to the one applied to Hill-type model for extrafusal fibers, making our proposed model more easily integrated in multi-body simulations.
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Affiliation(s)
- Pablo F S Chacon
- Institute for Modeling and Simulation of Biomechanical Systems, University of Stuttgart, Stuttgart, Germany
| | - Maria Hammer
- Institute for Modeling and Simulation of Biomechanical Systems, University of Stuttgart, Stuttgart, Germany
- Stuttgart Center for Simulation Science, University of Stuttgart, Stuttgart, Germany
| | - Isabell Wochner
- Institute for Modeling and Simulation of Biomechanical Systems, University of Stuttgart, Stuttgart, Germany
- Stuttgart Center for Simulation Science, University of Stuttgart, Stuttgart, Germany
- Institute of Computer Engineering, University of Heidelberg, Heidelberg, Germany
| | - Johannes R Walter
- Institute for Modeling and Simulation of Biomechanical Systems, University of Stuttgart, Stuttgart, Germany
- Max Planck Institute for Intelligent Systems, Stuttgart, Germany
| | - Syn Schmitt
- Institute for Modeling and Simulation of Biomechanical Systems, University of Stuttgart, Stuttgart, Germany
- Stuttgart Center for Simulation Science, University of Stuttgart, Stuttgart, Germany
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Crump KB, Alminnawi A, Bermudez‐Lekerika P, Compte R, Gualdi F, McSweeney T, Muñoz‐Moya E, Nüesch A, Geris L, Dudli S, Karppinen J, Noailly J, Le Maitre C, Gantenbein B. Cartilaginous endplates: A comprehensive review on a neglected structure in intervertebral disc research. JOR Spine 2023; 6:e1294. [PMID: 38156054 PMCID: PMC10751983 DOI: 10.1002/jsp2.1294] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/29/2023] [Revised: 09/15/2023] [Accepted: 09/26/2023] [Indexed: 12/30/2023] Open
Abstract
The cartilaginous endplates (CEP) are key components of the intervertebral disc (IVD) necessary for sustaining the nutrition of the disc while distributing mechanical loads and preventing the disc from bulging into the adjacent vertebral body. The size, shape, and composition of the CEP are essential in maintaining its function, and degeneration of the CEP is considered a contributor to early IVD degeneration. In addition, the CEP is implicated in Modic changes, which are often associated with low back pain. This review aims to tackle the current knowledge of the CEP regarding its structure, composition, permeability, and mechanical role in a healthy disc, how they change with degeneration, and how they connect to IVD degeneration and low back pain. Additionally, the authors suggest a standardized naming convention regarding the CEP and bony endplate and suggest avoiding the term vertebral endplate. Currently, there is limited data on the CEP itself as reported data is often a combination of CEP and bony endplate, or the CEP is considered as articular cartilage. However, it is clear the CEP is a unique tissue type that differs from articular cartilage, bony endplate, and other IVD tissues. Thus, future research should investigate the CEP separately to fully understand its role in healthy and degenerated IVDs. Further, most IVD regeneration therapies in development failed to address, or even considered the CEP, despite its key role in nutrition and mechanical stability within the IVD. Thus, the CEP should be considered and potentially targeted for future sustainable treatments.
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Affiliation(s)
- Katherine B. Crump
- Tissue Engineering for Orthopaedics & Mechanobiology, Bone & Joint Program, Department for BioMedical Research (DBMR), Medical FacultyUniversity of BernBernSwitzerland
- Department of Orthopaedic Surgery and Traumatology, InselspitalBern University Hospital, Medical Faculty, University of BernBernSwitzerland
- Graduate School for Cellular and Biomedical Sciences (GCB)University of BernBernSwitzerland
| | - Ahmad Alminnawi
- GIGA In Silico MedicineUniversity of LiègeLiègeBelgium
- Skeletal Biology and Engineering Research Center, KU LeuvenLeuvenBelgium
- Biomechanics Research Unit, KU LeuvenLeuvenBelgium
| | - Paola Bermudez‐Lekerika
- Tissue Engineering for Orthopaedics & Mechanobiology, Bone & Joint Program, Department for BioMedical Research (DBMR), Medical FacultyUniversity of BernBernSwitzerland
- Department of Orthopaedic Surgery and Traumatology, InselspitalBern University Hospital, Medical Faculty, University of BernBernSwitzerland
- Graduate School for Cellular and Biomedical Sciences (GCB)University of BernBernSwitzerland
| | - Roger Compte
- Twin Research & Genetic EpidemiologySt. Thomas' Hospital, King's College LondonLondonUK
| | - Francesco Gualdi
- Institut Hospital del Mar d'Investigacions Mèdiques (IMIM)BarcelonaSpain
| | - Terence McSweeney
- Research Unit of Health Sciences and TechnologyUniversity of OuluOuluFinland
| | - Estefano Muñoz‐Moya
- BCN MedTech, Department of Information and Communication TechnologiesUniversitat Pompeu FabraBarcelonaSpain
| | - Andrea Nüesch
- Division of Clinical Medicine, School of Medicine and Population HealthUniversity of SheffieldSheffieldUK
| | - Liesbet Geris
- GIGA In Silico MedicineUniversity of LiègeLiègeBelgium
- Skeletal Biology and Engineering Research Center, KU LeuvenLeuvenBelgium
- Biomechanics Research Unit, KU LeuvenLeuvenBelgium
| | - Stefan Dudli
- Center of Experimental RheumatologyDepartment of Rheumatology, University Hospital Zurich, University of ZurichZurichSwitzerland
- Department of Physical Medicine and RheumatologyBalgrist University Hospital, Balgrist Campus, University of ZurichZurichSwitzerland
| | - Jaro Karppinen
- Research Unit of Health Sciences and TechnologyUniversity of OuluOuluFinland
- Finnish Institute of Occupational HealthOuluFinland
- Rehabilitation Services of South Karelia Social and Health Care DistrictLappeenrantaFinland
| | - Jérôme Noailly
- BCN MedTech, Department of Information and Communication TechnologiesUniversitat Pompeu FabraBarcelonaSpain
| | - Christine Le Maitre
- Division of Clinical Medicine, School of Medicine and Population HealthUniversity of SheffieldSheffieldUK
| | - Benjamin Gantenbein
- Tissue Engineering for Orthopaedics & Mechanobiology, Bone & Joint Program, Department for BioMedical Research (DBMR), Medical FacultyUniversity of BernBernSwitzerland
- Department of Orthopaedic Surgery and Traumatology, InselspitalBern University Hospital, Medical Faculty, University of BernBernSwitzerland
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Rockenfeller R. Three-dimensional spinal shape changes during daily activities. Comput Biol Med 2023; 164:107236. [PMID: 37506450 DOI: 10.1016/j.compbiomed.2023.107236] [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: 06/12/2023] [Revised: 06/22/2023] [Accepted: 07/07/2023] [Indexed: 07/30/2023]
Abstract
MOTIVATION Intuitive assessment of spinal motion poses a tremendous challenge to both physicians and computer modelers. On the one side, medically detailed analyses of spinal shapes, such as computer tomography or X-ray images, are usually subject to static boundary constraints, thereby omitting dynamic information. On the other side, complex computer simulations often lack proper calibration aside from few control points, particularly regarding the three-dimensional arrangement of the spinal column and its idiomotion. PURPOSE Here, we investigate whether the full three-dimensional changes in spinal shape over time can be concisely detected and depicted. Further, we assess which parts of the spine undergo significant changes during various daily activities. METHODS We utilize a set of previously published motion capture data from the spinous processes (sacrum up to vertebra C7) of 17 healthy individuals performing the daily tasks of standing, walking, stair climbing, sitting down, and lifting. These three-dimensional, time-dependent marker positions were approximated by a Bézier curve at each time instant. The curves' characteristics, i.e.curvature and torsion, were calculated and juxtaposed for each individual and each activity over time. A statistical parametric mapping revealed significant changes in spinal shape. RESULTS We found the individual spinal shape characteristics being recognizably preserved during all activities. The walking task did not significantly alter the spinal curvature, while sitting and forward bending significantly altered the lumber and whole spine curvature, respectively. Torsion did not show any significant alterations. CONCLUSION Based on these results, we suggest that individualized dynamic information on spinal shapes can improve (i) the evaluation of (healthy) motion characteristics, (ii) the detection of pathologies, and (iii) individualized computer simulation models.
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Wang F, Sun R, Zhang SD, Wu XT. Comparison of thoracolumbar versus non-thoracolumbar osteoporotic vertebral compression fractures in risk factors, vertebral compression degree and pre-hospital back pain. J Orthop Surg Res 2023; 18:643. [PMID: 37649026 PMCID: PMC10469467 DOI: 10.1186/s13018-023-04140-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/24/2023] [Accepted: 08/25/2023] [Indexed: 09/01/2023] Open
Abstract
BACKGROUND Thoracolumbar spine is at high risk of osteoporotic vertebral compression fractures (OVCF). This study aimed to identify the differences in risk factors, vertebral compression degree and back pain characteristics of thoracolumbar OVCF (TL-OVCF) and non-thoracolumbar OVCF (nTL-OVCF). METHODS OVCF patients hospitalized in a spine center between June 2016 and October 2020 were retrospectively studied. Demographics, comorbidity, spine trauma, bone mineral density, duration of pre-hospital back pain, extent of vertebral marrow edema, and degree of vertebral compression of patients with nTL-OVCF were summarized and compared to those with TL-OVCF. RESULTS A total of 944 patients with acute single-segment OVCF were included. There were 708 (75.0%) TL-OVCF located in T11-L2 and 236 (25.0%) nTL-OVCF in lower lumbar (L3-L5) and middle thoracic (T5-T10) spine. The female-male ratio was 4.1 in nTL-OVCF and differed not significantly from TL-OVCF. The middle thoracic OVCF were older and had higher comorbidity of coronary heart disease (21.3%) and cerebral infarction (36.3%) than TL-OVCF (12.1% and 20.6%). In nTL-OVCF the ratio of apparent spine trauma (44.9%) and pre-hospital back pain ≤ 1 week (47.5%) was lower than in TL-OVCF (66.9% and 62.6%). The T-score value of lumbar spine was - 2.99 ± 1.11, - 3.24 ± 1.14, - 3.05 ± 1.40 in < 70, 70-80, > 80 years old TL-OVCF and differed not significantly from nTL-OVCF. The lower lumbar OVCF had more cranial type of vertebral marrow edema (21.8%) and fewer concurrent lumbodorsal fasciitis (30.8%) than TL-OVCF (16.8% and 43.4%). In TL-OVCF the anterior-posterior vertebral height ratio was lower with back pain for > 4 weeks than for ≤ 1, 1-2, and 2-4 weeks. In nTL-OVCF the degree of vertebral compression differed not significantly with pre-hospital back pain for ≤ 1, 1-2, 2-4, and > 4 weeks. CONCLUSIONS Thoracolumbar spine has 2-folds higher risk of OVCF than non-thoracolumbar spine. Non-thoracolumbar OVCF are not associated with female gender, apparent spine trauma or poor bone mineral density, but tend to maintain the degree of vertebral compression and cause longer duration of pre-hospital back pain.
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Affiliation(s)
- Feng Wang
- Department of Spine Surgery, Zhongda Hospital, School of Medicine, Southeast University, 87# Dingjiaqiao Road, Nanjing, 210009, China
- Surgery Research Center, School of Medicine, Southeast University, 87# Dingjiaqiao Road, Nanjing, 210009, China
| | - Rui Sun
- Department of Spine Surgery, Zhongda Hospital, School of Medicine, Southeast University, 87# Dingjiaqiao Road, Nanjing, 210009, China
- Surgery Research Center, School of Medicine, Southeast University, 87# Dingjiaqiao Road, Nanjing, 210009, China
| | - Shao-Dong Zhang
- Department of Spine Surgery, Zhongda Hospital, School of Medicine, Southeast University, 87# Dingjiaqiao Road, Nanjing, 210009, China.
- Surgery Research Center, School of Medicine, Southeast University, 87# Dingjiaqiao Road, Nanjing, 210009, China.
| | - Xiao-Tao Wu
- Department of Spine Surgery, Zhongda Hospital, School of Medicine, Southeast University, 87# Dingjiaqiao Road, Nanjing, 210009, China
- Surgery Research Center, School of Medicine, Southeast University, 87# Dingjiaqiao Road, Nanjing, 210009, China
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Meszaros-Beller L, Hammer M, Schmitt S, Pivonka P. Effect of neglecting passive spinal structures: a quantitative investigation using the forward-dynamics and inverse-dynamics musculoskeletal approach. Front Physiol 2023; 14:1135531. [PMID: 37324394 PMCID: PMC10264677 DOI: 10.3389/fphys.2023.1135531] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/01/2023] [Accepted: 04/28/2023] [Indexed: 06/17/2023] Open
Abstract
Purpose: Inverse-dynamics (ID) analysis is an approach widely used for studying spine biomechanics and the estimation of muscle forces. Despite the increasing structural complexity of spine models, ID analysis results substantially rely on accurate kinematic data that most of the current technologies are not capable to provide. For this reason, the model complexity is drastically reduced by assuming three degrees of freedom spherical joints and generic kinematic coupling constraints. Moreover, the majority of current ID spine models neglect the contribution of passive structures. The aim of this ID analysis study was to determine the impact of modelled passive structures (i.e., ligaments and intervertebral discs) on remaining joint forces and torques that muscles must balance in the functional spinal unit. Methods: For this purpose, an existing generic spine model developed for the use in the demoa software environment was transferred into the musculoskeletal modelling platform OpenSim. The thoracolumbar spine model previously used in forward-dynamics (FD) simulations provided a full kinematic description of a flexion-extension movement. By using the obtained in silico kinematics, ID analysis was performed. The individual contribution of passive elements to the generalised net joint forces and torques was evaluated in a step-wise approach increasing the model complexity by adding individual biological structures of the spine. Results: The implementation of intervertebral discs and ligaments has significantly reduced compressive loading and anterior torque that is attributed to the acting net muscle forces by -200% and -75%, respectively. The ID model kinematics and kinetics were cross-validated against the FD simulation results. Conclusion: This study clearly shows the importance of incorporating passive spinal structures on the accurate computation of remaining joint loads. Furthermore, for the first time, a generic spine model was used and cross-validated in two different musculoskeletal modelling platforms, i.e., demoa and OpenSim, respectively. In future, a comparison of neuromuscular control strategies for spinal movement can be investigated using both approaches.
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Affiliation(s)
- Laura Meszaros-Beller
- School of Mechanical, Medical and Process Engineering, Queensland University of Technology, Brisbane, QLD, Australia
- Centre for Biomedical Technologies, Queensland University of Technology, Brisbane, QLD, Australia
- Institute for Modelling and Simulation of Biomechanical Systems, University of Stuttgart, Stuttgart, Germany
| | - Maria Hammer
- Institute for Modelling and Simulation of Biomechanical Systems, University of Stuttgart, Stuttgart, Germany
- Stuttgart Center for Simulation Science (SC SimTech), University of Stuttgart, Stuttgart, Germany
| | - Syn Schmitt
- School of Mechanical, Medical and Process Engineering, Queensland University of Technology, Brisbane, QLD, Australia
- Institute for Modelling and Simulation of Biomechanical Systems, University of Stuttgart, Stuttgart, Germany
- Stuttgart Center for Simulation Science (SC SimTech), University of Stuttgart, Stuttgart, Germany
| | - Peter Pivonka
- School of Mechanical, Medical and Process Engineering, Queensland University of Technology, Brisbane, QLD, Australia
- Centre for Biomedical Technologies, Queensland University of Technology, Brisbane, QLD, Australia
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10
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Meszaros-Beller L, Hammer M, Riede JM, Pivonka P, Little JP, Schmitt S. Effects of geometric individualisation of a human spine model on load sharing: neuro-musculoskeletal simulation reveals significant differences in ligament and muscle contribution. Biomech Model Mechanobiol 2023; 22:669-694. [PMID: 36602716 PMCID: PMC10097810 DOI: 10.1007/s10237-022-01673-3] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2021] [Accepted: 12/08/2022] [Indexed: 01/06/2023]
Abstract
In spine research, two possibilities to generate models exist: generic (population-based) models representing the average human and subject-specific representations of individuals. Despite the increasing interest in subject specificity, individualisation of spine models remains challenging. Neuro-musculoskeletal (NMS) models enable the analysis and prediction of dynamic motions by incorporating active muscles attaching to bones that are connected using articulating joints under the assumption of rigid body dynamics. In this study, we used forward-dynamic simulations to compare a generic NMS multibody model of the thoracolumbar spine including fully articulated vertebrae, detailed musculature, passive ligaments and linear intervertebral disc (IVD) models with an individualised model to assess the contribution of individual biological structures. Individualisation was achieved by integrating skeletal geometry from computed tomography and custom-selected muscle and ligament paths. Both models underwent a gravitational settling process and a forward flexion-to-extension movement. The model-specific load distribution in an equilibrated upright position and local stiffness in the L4/5 functional spinal unit (FSU) is compared. Load sharing between occurring internal forces generated by individual biological structures and their contribution to the FSU stiffness was computed. The main finding of our simulations is an apparent shift in load sharing with individualisation from an equally distributed element contribution of IVD, ligaments and muscles in the generic spine model to a predominant muscle contribution in the individualised model depending on the analysed spine level.
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Affiliation(s)
- Laura Meszaros-Beller
- School of Mechanical, Medical and Process Engineering, Queensland University of Technology, Brisbane, Australia.,Institute for Modelling and Simulation of Biomechanical Systems, University of Stuttgart, Stuttgart, Germany
| | - Maria Hammer
- Institute for Modelling and Simulation of Biomechanical Systems, University of Stuttgart, Stuttgart, Germany.,Stuttgart Center for Simulation Science (SC SimTech), University of Stuttgart, Stuttgart, Germany
| | - Julia M Riede
- Institute for Modelling and Simulation of Biomechanical Systems, University of Stuttgart, Stuttgart, Germany
| | - Peter Pivonka
- School of Mechanical, Medical and Process Engineering, Queensland University of Technology, Brisbane, Australia
| | - J Paige Little
- School of Mechanical, Medical and Process Engineering, Queensland University of Technology, Brisbane, Australia
| | - Syn Schmitt
- School of Mechanical, Medical and Process Engineering, Queensland University of Technology, Brisbane, Australia. .,Institute for Modelling and Simulation of Biomechanical Systems, University of Stuttgart, Stuttgart, Germany. .,Stuttgart Center for Simulation Science (SC SimTech), University of Stuttgart, Stuttgart, Germany.
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11
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Knapik GG, Mendel E, Bourekas E, Marras WS. Computational lumbar spine models: A literature review. Clin Biomech (Bristol, Avon) 2022; 100:105816. [PMID: 36435080 DOI: 10.1016/j.clinbiomech.2022.105816] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/28/2022] [Revised: 10/26/2022] [Accepted: 11/08/2022] [Indexed: 11/15/2022]
Abstract
BACKGROUND Computational spine models of various types have been employed to understand spine function, assess the risk that different activities pose to the spine, and evaluate techniques to prevent injury. The areas in which these models are applied has expanded greatly, potentially beyond the appropriate scope of each, given their capabilities. A comprehensive understanding of the components of these models provides insight into their current capabilities and limitations. METHODS The objective of this review was to provide a critical assessment of the different characteristics of model elements employed across the spectrum of lumbar spine modeling and in newer combined methodologies to help better evaluate existing studies and delineate areas for future research and refinement. FINDINGS A total of 155 studies met selection criteria and were included in this review. Most current studies use either highly detailed Finite Element models or simpler Musculoskeletal models driven with in vivo data. Many models feature significant geometric or loading simplifications that limit their realism and validity. Frequently, studies only create a single model and thus can't account for the impact of subject variability. The lack of model representation for certain subject cohorts leaves significant gaps in spine knowledge. Combining features from both types of modeling could result in more accurate and predictive models. INTERPRETATION Development of integrated models combining elements from different model types in a framework that enables the evaluation of larger populations of subjects could address existing voids and enable more realistic representation of the biomechanics of the lumbar spine.
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Affiliation(s)
- Gregory G Knapik
- Spine Research Institute, The Ohio State University, 210 Baker Systems, 1971 Neil Avenue, Columbus, OH 43210, USA.
| | - Ehud Mendel
- Department of Neurosurgery, Yale University, New Haven, CT 06510, USA
| | - Eric Bourekas
- Department of Radiology, The Ohio State University, Columbus, OH 43210, USA
| | - William S Marras
- Spine Research Institute, The Ohio State University, 210 Baker Systems, 1971 Neil Avenue, Columbus, OH 43210, USA
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12
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Degenerative Disc Disease of the Spine: From Anatomy to Pathophysiology and Radiological Appearance, with Morphological and Functional Considerations. J Pers Med 2022; 12:jpm12111810. [PMID: 36579533 PMCID: PMC9698646 DOI: 10.3390/jpm12111810] [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: 10/05/2022] [Revised: 10/28/2022] [Accepted: 10/30/2022] [Indexed: 11/06/2022] Open
Abstract
Degenerative disc disease is a common manifestation in routine imaging of the spine; this finding is partly attributable to physiological aging and partly to a pathological condition, and sometimes this distinction is simply not clear. In this review, we start focusing on disc anatomy and pathophysiology and try to correlate them with radiological aspects. Furthermore, there is a special focus on degenerative disc disease terminology, and, finally, some considerations regarding disc morphology and its specific function, as well as the way in which these aspects change in degenerative disease. Radiologists, clinicians and spine surgeons should be familiar with these aspects since they have an impact on everyday clinical practice.
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13
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Wochner I, Nölle LV, Martynenko OV, Schmitt S. ‘Falling heads’: investigating reflexive responses to head–neck perturbations. Biomed Eng Online 2022; 21:25. [PMID: 35429975 PMCID: PMC9013062 DOI: 10.1186/s12938-022-00994-9] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2021] [Accepted: 03/29/2022] [Indexed: 11/10/2022] Open
Abstract
Abstract
Background
Reflexive responses to head–neck perturbations affect the injury risk in many different situations ranging from sports-related impact to car accident scenarios. Although several experiments have been conducted to investigate these head–neck responses to various perturbations, it is still unclear why and how individuals react differently and what the implications of these different responses across subjects on the potential injuries might be. Therefore, we see a need for both experimental data and biophysically valid computational Human Body Models with bio-inspired muscle control strategies to understand individual reflex responses better.
Methods
To address this issue, we conducted perturbation experiments of the head–neck complex and used this data to examine control strategies in a simulation model. In the experiments, which we call ’falling heads’ experiments, volunteers were placed in a supine and a prone position on a table with an additional trapdoor supporting the head. This trapdoor was suddenly released, leading to a free-fall movement of the head until reflexive responses of muscles stopped the downwards movement.
Results
We analysed the kinematic, neuronal and dynamic responses for all individuals and show their differences for separate age and sex groups. We show that these results can be used to validate two simple reflex controllers which are able to predict human biophysical movement and modulate the response necessary to represent a large variability of participants.
Conclusions
We present characteristic parameters such as joint stiffness, peak accelerations and latency times. Based on this data, we show that there is a large difference in the individual reflexive responses between participants. Furthermore, we show that the perturbation direction (supine vs. prone) significantly influences the measured kinematic quantities. Finally, ’falling heads’ experiments data are provided open-source to be used as a benchmark test to compare different muscle control strategies and to validate existing active Human Body Models directly.
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14
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Prado-Novoa M, Perez-Sanchez L, Estebanez B, Moreno-Vegas S, Perez-Blanca A. Influence of Loading Conditions on the Mechanical Performance of Multifilament Coreless UHMWPE Sutures Used in Orthopaedic Surgery. MATERIALS 2022; 15:ma15072573. [PMID: 35407907 PMCID: PMC9000354 DOI: 10.3390/ma15072573] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 03/01/2022] [Revised: 03/28/2022] [Accepted: 03/30/2022] [Indexed: 02/05/2023]
Abstract
This work studies the influence of loading velocity and previous cyclic loading history on the stiffness and strength of a multifilament coreless ultra-high-molecular-weight polyethylene (UHMWPE) surgical suture. Thread samples (n = 8) were subjected to a load-to-failure test at 0.1, 0.5, 1, 5, and 10 mm/s without previous loading history and after 10 cycles of loading at 1-10 N, 1-30 N, and 1-50 N. The experimental data were fitted to mathematical models to compute the stress-strain relation and the strength of the suture. The bilinear model involving two stress-strain ratios for low- and high-strain intervals was the best fit. The ratio in the low-strain range rose with loading speed, showing mean increases of 5.9%, 6.5%, 7.9%, and 7.3% between successive loading speeds. Without a previous loading history, this ratio was less than half than that at high strain. However, 10 cycles of 1-30 N or 1-50 N significantly increased the stress-strain ratio at a low strain level by 135% and 228%, respectively. The effect persisted after 2 min but vanished after 24 h. No influence was found on the suture strength. In conclusion, the stiffness of the studied suture was influenced by the strain level, loading velocity, and recent cyclic loading history. Conversely, the suture strength was not affected.
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Affiliation(s)
- Maria Prado-Novoa
- Clinical Biomechanics Laboratory of Andalusia, University of Malaga, Calle Dr. Ortiz Ramos s/n, 29071 Malaga, Spain; (L.P.-S.); (B.E.); (S.M.-V.); (A.P.-B.)
- Correspondence:
| | - Laura Perez-Sanchez
- Clinical Biomechanics Laboratory of Andalusia, University of Malaga, Calle Dr. Ortiz Ramos s/n, 29071 Malaga, Spain; (L.P.-S.); (B.E.); (S.M.-V.); (A.P.-B.)
- Telecomunication Research Institute (TELMA), University of Malaga, E.T.S. Ingenieria de Telecomunicaciones, Bulevar Louis Pasteur 35, 29010 Malaga, Spain
| | - Belen Estebanez
- Clinical Biomechanics Laboratory of Andalusia, University of Malaga, Calle Dr. Ortiz Ramos s/n, 29071 Malaga, Spain; (L.P.-S.); (B.E.); (S.M.-V.); (A.P.-B.)
| | - Salvador Moreno-Vegas
- Clinical Biomechanics Laboratory of Andalusia, University of Malaga, Calle Dr. Ortiz Ramos s/n, 29071 Malaga, Spain; (L.P.-S.); (B.E.); (S.M.-V.); (A.P.-B.)
- Biomedical Research Institute of Malaga, Calle Dr. Miguel Díaz Recio, 28, 29010 Malaga, Spain
| | - Ana Perez-Blanca
- Clinical Biomechanics Laboratory of Andalusia, University of Malaga, Calle Dr. Ortiz Ramos s/n, 29071 Malaga, Spain; (L.P.-S.); (B.E.); (S.M.-V.); (A.P.-B.)
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15
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Abstract
Optimal endoscopic operations incorporate ergonomic principles into the endoscopy environment benefiting endoscopists, endoscopy unit personnel, and patients. A high prevalence of occupational musculoskeletal injuries is well established among endoscopists and gastroenterology nurses. Ergonomics can be integrated into all facets of the endoscopy unit including scheduling, endoscopy unit design, training programs, and investment in technology. Preprocedure, intraprocedure, and postprocedure areas should aim to deliver patient safety, privacy, and comfort, while also supporting endoscopists and staff with adjustable rooms and effective work flows. Team-wide educational initiatives can improve ergonomic awareness. These strategies help mitigate risks for musculoskeletal injuries and can lead to increased productivity. The COVID-19 area brings novel challenges to endoscopy.
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Affiliation(s)
- Anna M Lipowska
- Division of Gastroenterology and Hepatology, University of Illinois at Chicago, 840 South Wood Street, CSB Suite 741 (MC 716), Chicago, IL 60612, USA.
| | - Amandeep K Shergill
- Division of Gastroenterology and Hepatology, San Francisco Veterans Affairs Medical Center and University of California, 4150 Clement Street, VA 111B/ GI Section, San Francisco, CA 94121, USA
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16
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Rockenfeller R, Hammer M, Riede JM, Schmitt S, Lawonn K. Intuitive assessment of modeled lumbar spinal motion by clustering and visualization of finite helical axes. Comput Biol Med 2021; 135:104528. [PMID: 34166878 DOI: 10.1016/j.compbiomed.2021.104528] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/08/2021] [Revised: 05/18/2021] [Accepted: 05/22/2021] [Indexed: 11/29/2022]
Abstract
A variety of medical imaging procedures, cadaver experiments, and computer models have been utilized to capture, depict, and understand the motion of the human lumbar spine. Particular interest lies in assessing the relative movement between two adjacent vertebrae, which can be represented by a temporal evolution of finite helical axes (FHA). Mathematically, this FHA evolution constitutes a seven-dimensional quantity: one dimension for the time, two for the (normalized) direction vector, another two for the (unique) position vector, as well as one for each the angle of rotation around and the amount of translation along the axis. Predominantly in the literature, however, movements are assumed to take place in certain physiological planes on which FHA are projected. The resulting three-dimensional quantity - the so-called centrode - is easily presentable but leaves out substantial pieces of available data. Here, we investigate and assess several possibilities to visualize subsets of FHA data of increasing dimensionality. Finally, we utilize an agglomerative hierarchical clustering algorithm and propose a novel visualization technique, namely the quiver principal axis plot (QPAP), to depict the entirety of information inherent to hundreds or thousands of FHA. The QPAP method is applied to flexion-extension, lateral bending, and axial rotation movements of a lumbar spine within both a reduced model as well as a complex upper body system.
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Affiliation(s)
- Robert Rockenfeller
- Mathematical Institute, University Koblenz-Landau, Universitätsstr. 1, 56070, Koblenz, Germany.
| | - Maria Hammer
- Institute for Modelling and Simulation of Biomechanical Systems and Stuttgart Center for Simulation Science (SimTech), University Stuttgart, Pfaffenwaldring 5a, 70569, Stuttgart, Germany
| | - Julia M Riede
- Institute for Modelling and Simulation of Biomechanical Systems and Stuttgart Center for Simulation Science (SimTech), University Stuttgart, Pfaffenwaldring 5a, 70569, Stuttgart, Germany
| | - Syn Schmitt
- Institute for Modelling and Simulation of Biomechanical Systems and Stuttgart Center for Simulation Science (SimTech), University Stuttgart, Pfaffenwaldring 5a, 70569, Stuttgart, Germany
| | - Kai Lawonn
- Faculty for Mathematics and Informatics, Friedrich-Schiller-University Jena, Ernst-Abbe-Platz 2, 07743, Jena, Germany
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17
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Guo J, Guo W, Ren G. Embodiment of intra-abdominal pressure in a flexible multibody model of the trunk and the spinal unloading effects during static lifting tasks. Biomech Model Mechanobiol 2021; 20:1599-1626. [PMID: 34050846 DOI: 10.1007/s10237-021-01465-1] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2020] [Accepted: 05/07/2021] [Indexed: 11/28/2022]
Abstract
The role of intra-abdominal pressure (IAP) in spinal load reduction has remained controversial, partly because previous musculoskeletal models did not introduce the pressure generating mechanism. In this study, an integrated computational methodology is proposed to combine the IAP change with core muscle activations. An ideal gas relationship was introduced to calculate pressure distribution within the abdominal cavity. Additionally, based on flexible multibody dynamics, a muscle membrane element was developed by incorporating the muscular fiber deformation, inter-fiber stiffness, and volume constancy. This element was then utilized in discretizing the diaphragm and transversus abdominis, forming an IAP-muscle coupling system of the abdominal cavity. Based on this methodology, a forward dynamic simulation of spinal flexion was presented to examine the unloading effect of abdominal breathing. The results confirm that core muscle contraction during the abdominal breathing cycle can substantially reduce the forces of spinal compression together with trunk extensor muscles, and this effect is more pronounced when the IAP increase is produced by contraction of the transversus abdominis. This unloading effect still holds even with the co-activation of other abdominal muscles, providing a potential choice when designing trunk movements during weight-lifting tasks.
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Affiliation(s)
- Jianqiao Guo
- MOE Key Laboratory of Dynamics and Control of Flight Vehicle, School of Aerospace Engineering, Beijing Institute of Technology, Beijing, 100081, China.
| | - Wei Guo
- Air Force Medical Center, PLA, Beijing, 100142, China
| | - Gexue Ren
- Department of Engineering Mechanics, Tsinghua University, Beijing, 100084, China
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18
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Walter JR, Günther M, Haeufle DFB, Schmitt S. A geometry- and muscle-based control architecture for synthesising biological movement. BIOLOGICAL CYBERNETICS 2021; 115:7-37. [PMID: 33590348 PMCID: PMC7925510 DOI: 10.1007/s00422-020-00856-4] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 09/12/2020] [Accepted: 12/28/2020] [Indexed: 06/12/2023]
Abstract
A key problem for biological motor control is to establish a link between an idea of a movement and the generation of a set of muscle-stimulating signals that lead to the movement execution. The number of signals to generate is thereby larger than the body's mechanical degrees of freedom in which the idea of the movement may be easily expressed, as the movement is actually executed in this space. A mathematical formulation that provides a solving link is presented in this paper in the form of a layered, hierarchical control architecture. It is meant to synthesise a wide range of complex three-dimensional muscle-driven movements. The control architecture consists of a 'conceptional layer', where the movement is planned, a 'structural layer', where the muscles are stimulated, and between both an additional 'transformational layer', where the muscle-joint redundancy is resolved. We demonstrate the operativeness by simulating human stance and squatting in a three-dimensional digital human model (DHM). The DHM considers 20 angular DoFs and 36 Hill-type muscle-tendon units (MTUs) and is exposed to gravity, while its feet contact the ground via reversible stick-slip interactions. The control architecture continuously stimulates all MTUs ('structural layer') based on a high-level, torque-based task formulation within its 'conceptional layer'. Desired states of joint angles (postural plan) are fed to two mid-level joint controllers in the 'transformational layer'. The 'transformational layer' communicates with the biophysical structures in the 'structural layer' by providing direct MTU stimulation contributions and further input signals for low-level MTU controllers. Thereby, the redundancy of the MTU stimulations with respect to the joint angles is resolved, i.e. a link between plan and execution is established, by exploiting some properties of the biophysical structures modelled. The resulting joint torques generated by the MTUs via their moment arms are fed back to the conceptional layer, closing the high-level control loop. Within our mathematical formulations of the Jacobian matrix-based layer transformations, we identify the crucial information for the redundancy solution to be the muscle moment arms, the stiffness relations of muscle and tendon tissue within the muscle model, and the length-stimulation relation of the muscle activation dynamics. The present control architecture allows the straightforward feeding of conceptional movement task formulations to MTUs. With this approach, the problem of movement planning is eased, as solely the mechanical system has to be considered in the conceptional plan.
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Affiliation(s)
- Johannes R Walter
- Institute for Modelling and Simulation of Biomechanical Systems, Computational Biophysics and Biorobotics, University of Stuttgart, Nobelstraße 15, 70569, Stuttgart, Germany.
| | - Michael Günther
- Institute for Modelling and Simulation of Biomechanical Systems, Computational Biophysics and Biorobotics, University of Stuttgart, Nobelstraße 15, 70569, Stuttgart, Germany
| | - Daniel F B Haeufle
- Center of Neurology, Hertie Institute for Clinical Brain Research, Otfried-Müller-Strasse 25, 72076, Tübingen, Germany
| | - Syn Schmitt
- Institute for Modelling and Simulation of Biomechanical Systems, Computational Biophysics and Biorobotics, University of Stuttgart, Nobelstraße 15, 70569, Stuttgart, Germany
- Stuttgart Center of Simulation Science (SimTech), Pfaffenwaldring 7a, 70569, Stuttgart, Germany
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19
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Günther M, Mörl F. Giraffes and hominins: reductionist model predictions of compressive loads at the spine base for erect exponents of the animal kingdom. Biol Open 2021; 10:bio.057224. [PMID: 33380420 PMCID: PMC7847267 DOI: 10.1242/bio.057224] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
In humans, compressive stress on intervertebral discs is commonly deployed as a measurand for assessing the loads that act within the spine. Examining this physical quantity is crucially beneficial: the intradiscal pressure can be directly measured in vivo in humans, and is immediately related to compressive stress. Hence, measured intradiscal pressure data are very useful for validating such biomechanical animal models that have the spine incorporated, and can, thus, compute compressive stress values. Here, we use human intradiscal pressure data to verify the predictions of a reductionist spine model, which has in fact only one joint degree of freedom. We calculate the pulling force of one lumped anatomical structure that acts past this (intervertebral) joint at the base of the spine, lumbar in hominins, cervical in giraffes, to compensate the torque that is induced by the weight of all masses located cranially to the base. Given morphometric estimates of the human and australopith trunks, respectively, and the giraffe's neck, as well as the respective structures’ lever arms and disc areas, we predict, for all three species, the compressive stress on the intervertebral disc at the spine base, while systematically varying the angular orientation of the species’ spinal columns with respect to gravity. The comparison between these species demonstrates that hominin everyday compressive disc stresses are lower than those in big quadrupedal animals. Within each species, erecting the spine from being bent forward by, for example, thirty degrees to fully upright posture reduces the compressive disc stress roughly to a third. We conclude that erecting the spine immediately allows the carrying of extra loads of the order of body weight, and yet the compressive disc stress is lower than in a moderately forward-bent posture with no extra load. Summary: Using a simple biomechanical model, we predict the compressive stress on vertebrates’ intervertebral discs loaded by all cranial masses being held anywhere between fully upright and horizontal bow.
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Affiliation(s)
- Michael Günther
- Institut für Modellierung und Simulation Biomechanischer Systeme, Computational Biophysics and Biorobotics, Universität Stuttgart, Nobelstraße 15, 70569 Stuttgart, Germany
| | - Falk Mörl
- Forschungsgesellschaft für Angewandte Systemsicherheit und Arbeitsmedizin mbH, Biomechanik & Ergonomie, Lucas-Cranach Platz 2, 99097 Erfurt, Germany
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20
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Beaucage-Gauvreau E, Brandon SCE, Robertson WSP, Fraser R, Freeman BJC, Graham RB, Thewlis D, Jones CF. Lumbar spine loads are reduced for activities of daily living when using a braced arm-to-thigh technique. 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 2020; 30:1035-1042. [PMID: 33156439 DOI: 10.1007/s00586-020-06631-0] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/26/2020] [Revised: 08/10/2020] [Accepted: 10/06/2020] [Indexed: 11/29/2022]
Abstract
PURPOSE To evaluate the effect of the braced arm-to-thigh technique (BATT) (versus self-selected techniques) on three-dimensional trunk kinematics and spinal loads for three common activities of daily living (ADLs) simulated in the laboratory: weeding (gardening), reaching for an object in a low cupboard, and car egress using the two-legs out technique. METHODS Ten young healthy males performed each task using a self-selected technique, and then using the BATT. The pulling action of weeding was simulated using a magnet placed on a steel plate. Cupboard and car egress tasks were simulated using custom apparatus representing the dimensions of a kitchen cabinet and a medium-sized Australian car, respectively. Three-dimensional trunk kinematics and L4/L5 spinal loads were estimated using the Lifting Full-Body OpenSim model and compared between techniques. Paired t-tests were used to compare peak values between methods (self-selected vs BATT). RESULTS The BATT significantly reduced peak extension moments (13-51%), and both compression (27-45%) and shear forces (31-62%) at L4/L5, compared to self-selected techniques for all three tasks (p < 0.05). Lateral bending angles increased with the BATT for weeding and cupboard tasks, but these changes were expected as the BATT inherently introduces asymmetric trunk motion. CONCLUSION The BATT substantially reduced L4/L5 extension moments, and L4/L5 compression and shear forces, compared to self-selected methods, for three ADLs, in a small cohort of ten young healthy males without prior history of back pain. These study findings can be used to inform safe procedures for these three ADLs, as the results are considered representative of a mature population.
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Affiliation(s)
- Erica Beaucage-Gauvreau
- Centre for Orthopaedic & Trauma Research, Adelaide Medical School, The University of Adelaide, Level 7, Adelaide Health and Medical Sciences Building North Terrace, Adelaide, SA, 5000, Australia. .,Spinal Research Group, Centre for Orthopaedic & Trauma Research, Adelaide Medical School, The University of Adelaide, Level 7, Adelaide Health and Medical Sciences Building North Terrace, Adelaide, SA, 5000, Australia. .,School of Mechanical Engineering, The University of Adelaide, Engineering South Building, Adelaide, SA, 5000, Australia.
| | - Scott C E Brandon
- School of Engineering, The University of Guelph, Thornbrough Building 50 Stone Rd, Guelph, ON, Canada
| | - William S P Robertson
- School of Mechanical Engineering, The University of Adelaide, Engineering South Building, Adelaide, SA, 5000, Australia
| | - Robert Fraser
- The University of Adelaide Emeritus Consultant Spinal Surgery, Royal Adelaide Hospital, 160 East Terrace, Adelaide, SA, 5000, Australia
| | - Brian J C Freeman
- Centre for Orthopaedic & Trauma Research, Adelaide Medical School, The University of Adelaide, Level 7, Adelaide Health and Medical Sciences Building North Terrace, Adelaide, SA, 5000, Australia.,Spinal Injuries Unit, Royal Adelaide Hospital, 5G 531, Royal Adelaide Hospital, Port Road, Adelaide, SA, 5000, Australia
| | - Ryan B Graham
- School of Human Kinetics, The University of Ottawa, Ottawa, Lees, E260G, Canada
| | - Dominic Thewlis
- Centre for Orthopaedic & Trauma Research, Adelaide Medical School, The University of Adelaide, Level 7, Adelaide Health and Medical Sciences Building North Terrace, Adelaide, SA, 5000, Australia
| | - Claire F Jones
- Centre for Orthopaedic & Trauma Research, Adelaide Medical School, The University of Adelaide, Level 7, Adelaide Health and Medical Sciences Building North Terrace, Adelaide, SA, 5000, Australia.,Spinal Research Group, Centre for Orthopaedic & Trauma Research, Adelaide Medical School, The University of Adelaide, Level 7, Adelaide Health and Medical Sciences Building North Terrace, Adelaide, SA, 5000, Australia.,School of Mechanical Engineering, The University of Adelaide, Engineering South Building, Adelaide, SA, 5000, Australia
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21
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Rockenfeller R, Müller A, Damm N, Kosterhon M, Kantelhardt SR, Frank R, Gruber K. Muscle-driven and torque-driven centrodes during modeled flexion of individual lumbar spines are disparate. Biomech Model Mechanobiol 2020; 20:267-279. [PMID: 32939615 PMCID: PMC7892748 DOI: 10.1007/s10237-020-01382-9] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/06/2020] [Accepted: 08/24/2020] [Indexed: 11/25/2022]
Abstract
Lumbar spine biomechanics during the forward-bending of the upper body (flexion) are well investigated by both in vivo and in vitro experiments. In both cases, the experimentally observed relative motion of vertebral bodies can be used to calculate the instantaneous center of rotation (ICR). The timely evolution of the ICR, the centrode, is widely utilized for validating computer models and is thought to serve as a criterion for distinguishing healthy and degenerative motion patterns. While in vivo motion can be induced by physiological active structures (muscles), in vitro spinal segments have to be driven by external torque-applying equipment such as spine testers. It is implicitly assumed that muscle-driven and torque-driven centrodes are similar. Here, however, we show that centrodes qualitatively depend on the impetus. Distinction is achieved by introducing confidence regions (ellipses) that comprise centrodes of seven individual multi-body simulation models, performing flexion with and without preload. Muscle-driven centrodes were generally directed superior–anterior and tail-shaped, while torque-driven centrodes were located in a comparably narrow region close to the center of mass of the caudal vertebrae. We thus argue that centrodes resulting from different experimental conditions ought to be compared with caution. Finally, the applicability of our method regarding the analysis of clinical syndromes and the assessment of surgical methods is discussed.
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Affiliation(s)
- Robert Rockenfeller
- Mathematical Institute, University Koblenz-Landau, Universitätsstr. 1, 56070, Koblenz, Germany.
| | - Andreas Müller
- Institute for Medical Engineering and Information Processing (MTI Mittelrhein), University Koblenz-Landau, Universitätsstr. 1, 56070, Koblenz, Germany
- Mechanical Systems Engineering Laboratory, EMPA-Swiss Federal Laboratories for Materials Science and Technology, Ueberlandstr. 129, 8600 Dübendorf, Switzerland
| | - Nicolas Damm
- Institute for Medical Engineering and Information Processing (MTI Mittelrhein), University Koblenz-Landau, Universitätsstr. 1, 56070, Koblenz, Germany
| | - Michael Kosterhon
- Department of Neurosurgery, University Medical Centre, Johannes Gutenberg-University, Langenbeckstr. 1, 55131, Mainz, Germany
| | - Sven R Kantelhardt
- Department of Neurosurgery, University Medical Centre, Johannes Gutenberg-University, Langenbeckstr. 1, 55131, Mainz, Germany
| | - Rolfdieter Frank
- Mathematical Institute, University Koblenz-Landau, Universitätsstr. 1, 56070, Koblenz, Germany
| | - Karin Gruber
- Institute for Medical Engineering and Information Processing (MTI Mittelrhein), University Koblenz-Landau, Universitätsstr. 1, 56070, Koblenz, Germany
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