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Segain A, Sciume G, Pillet H, Rohan PY. In vivo mechanical response of thigh soft tissues under compression: A two-layer model allows an improved representation of the local tissue kinematics. J Mech Behav Biomed Mater 2024; 156:106584. [PMID: 38810544 DOI: 10.1016/j.jmbbm.2024.106584] [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: 12/22/2023] [Revised: 05/14/2024] [Accepted: 05/18/2024] [Indexed: 05/31/2024]
Abstract
Biomechanical parameters have the potential to be used as physical markers for prevention and diagnosis. Finite Element Analysis (FEA) is a widely used tool to evaluate these parameters in vivo. However, the development of clinically relevant FEA requires personalisation of the geometry, boundary conditions, and constitutive parameters. This contribution focuses on the characterisation of mechanical properties in vivo which remains a significant challenge for the community. The aim of this retrospective study is to evaluate the sensitivity of the computed elastic parameters (shear modulus of fat and muscle tissues) derived by inverse analysis as a function of the geometrical modelling assumption (homogenised monolayer vs bilayer) and the formulation of the cost function. The methodology presented here proposes to extract the experimental force-displacement response for each tissue layer (muscle and fat) and construct the associated Finite Element Model for each volunteer, based on data previously collected in our group (N = 7 volunteers) as reported in (Fougeron et al., 2020). The sensitivity analysis indicates that the choice of the cost function has minimal impact on the topology of the response surface in the parametric space. Each surface displays a valley of parameters that minimises the cost function. The constitutive properties of the thigh (reported as median ± interquartile range) were determined to be (μ=198±322Pa,α=37) for the monolayer and (μmuscle=1675±1127Pa,αmuscle=22±14,μfat=537±1131Pa,αfat=32±7) for the bilayer. A comparison of the homogenised monolayer and bilayer models showed that adding a layer reduces the error on the local force displacement curves, increasing the accuracy of the local kinematics of soft tissues during indentation. This allows for an increased understanding of load transmission in soft tissue. The comparison of the two models in terms of strains indicates that the modelling choice significantly influences the localization of maximal compressive strains. These results support the idea that the biomechanical community should conduct further work to develop reliable methodologies for estimating in vivo strain in soft tissue.
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Affiliation(s)
- Alexandre Segain
- Arts et Métiers Institute of Technology, Université Sorbonne Paris Nord, IBHGC - Institut de Biomécanique Humaine Georges Charpak, HESAM Université, F-75013, Paris, France.
| | - Giuseppe Sciume
- Arts et Metiers Institute of Technology, Univ. of Bordeaux, CNRS, Bordeaux INP, INRAE, I2M Bordeaux, Av d'Aquitaine, 33607, Pessac, France
| | - Hélène Pillet
- Arts et Métiers Institute of Technology, Université Sorbonne Paris Nord, IBHGC - Institut de Biomécanique Humaine Georges Charpak, HESAM Université, F-75013, Paris, France
| | - Pierre-Yves Rohan
- Arts et Métiers Institute of Technology, Université Sorbonne Paris Nord, IBHGC - Institut de Biomécanique Humaine Georges Charpak, HESAM Université, F-75013, Paris, France
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Xiang X, Zhang K, Qin Y, Ma X, Dai Y, Zhang X, Niu W, He P. Smart Cushions with Machine Learning-Enhanced Force Sensors for Pressure Injury Risk Assessment. ACS APPLIED MATERIALS & INTERFACES 2024. [PMID: 38995996 DOI: 10.1021/acsami.4c05964] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 07/14/2024]
Abstract
Prolonged sitting can easily result in pressure injury (PI) for certain people who have had strokes or spinal cord injuries. There are not many methods available for tracking contact surface pressure and shear force to evaluate the PI risk. Here, we propose a smart cushion that uses two-dimensional force sensors (2D-FSs) to measure the pressure and shear force in the buttocks. A machine learning algorithm is then used to compute the shear stresses in the gluteal muscles, which helps to determine the PI risk. The 2D-FS consists of a ferroelectret coaxial sensor (FCS) unit placed atop a ferroelectret film sensor (FFS) unit, allowing it to detect both vertical and horizontal forces simultaneously. To characterize and calibrate, two experimental approaches are applied: one involves simultaneously applying two perpendicular forces, and one involves applying a single force. To separate the two forces, the 2D-FS is decoupled using a deep neural network technique. Multiple FCSs are embedded to form a smart cushion, and a genetic algorithm-optimized backpropagation neural network is proposed and trained to predict the shear strain in the buttocks to prevent PI. By tracking the danger of PI, the smart cushion based on 2D-FSs may be further connected with home-based intelligent care platforms to increase patient equality for spinal cord injury patients and lower the expense of nursing or rehabilitation care.
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Affiliation(s)
- Xinhao Xiang
- Shanghai Yangzhi Rehabilitation Hospital (Shanghai Sunshine Rehabilitation Center), School of Medicine, Tongji University, Shanghai 201619, China
| | - Ke Zhang
- Shanghai Yangzhi Rehabilitation Hospital (Shanghai Sunshine Rehabilitation Center), School of Medicine, Tongji University, Shanghai 201619, China
- Department of Rehabilitation Sciences, School of Medicine, Tongji University, Shanghai 200092, China
| | - Yi Qin
- Shanghai Key Laboratory of Special Artificial Microstructure Materials and Technology, School of Physics Science and Engineering, Tongji University, Shanghai 200092, China
| | - Xingchen Ma
- Shanghai Key Laboratory of Special Artificial Microstructure Materials and Technology, School of Physics Science and Engineering, Tongji University, Shanghai 200092, China
| | - Ying Dai
- School of Aerospace Engineering and Applied Mechanics, Tongji University, Shanghai ,200092, China
| | - Xiaoqing Zhang
- Shanghai Key Laboratory of Special Artificial Microstructure Materials and Technology, School of Physics Science and Engineering, Tongji University, Shanghai 200092, China
| | - Wenxin Niu
- Shanghai Yangzhi Rehabilitation Hospital (Shanghai Sunshine Rehabilitation Center), School of Medicine, Tongji University, Shanghai 201619, China
- Department of Rehabilitation Sciences, School of Medicine, Tongji University, Shanghai 200092, China
| | - Pengfei He
- School of Aerospace Engineering and Applied Mechanics, Tongji University, Shanghai ,200092, China
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Kumagai A, Ohno N, Miyati T, Sugama J. Prediction of tissue deformation based on mechanical and physiological factors in the prone position during surgery. J Tissue Viability 2024:S0965-206X(24)00008-1. [PMID: 38378353 DOI: 10.1016/j.jtv.2024.02.004] [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: 09/03/2023] [Revised: 12/16/2023] [Accepted: 02/05/2024] [Indexed: 02/22/2024]
Abstract
AIM This study aimed to predict tissue deformation based on the pressure applied while lying in the prone position and physiological factors. METHODS Healthy volunteers were instructed to lie on mattresses of four different hardness levels (50, 87.5, 175, and 262.5 N). The order in which the mattresses were used was randomized per participant. Pressure at the iliac crests was measured using a pressure mapping sensor sheet. Participants were placed in the prone position for 10 min, with pressure data used from the latter 5 min. For the tissue deformation at the iliac crests, our previous study data were used. Multiple regression analysis was used to identify predictive mechanical and physiological factors. RESULTS The distance between the left and right greater trochanters, maximum interface pressure and age were significant predictors for compression of the skin and soft tissue. Significant predictors of internal soft tissue displacement were the distances between the left and right anterior superior iliac spines and greater trochanters. No factors predicted skin surface displacement. CONCLUSIONS Our study provided predictive factors that may be measured easily in a clinical setting to reduce the risk of pressure ulcers during surgery in the prone position.
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Affiliation(s)
- Ayumi Kumagai
- Faculty of Nursing and Social Welfare Science, Department of Nursing Science, Fukui Prefectural University, Eiheiji-Town, Fukui, Japan.
| | - Naoki Ohno
- Faculty of Health Sciences, Institute of Medical, Pharmaceutical and Health Sciences, Kanazawa University, Kanazawa, Ishikawa, Japan
| | - Tosiaki Miyati
- Faculty of Health Sciences, Institute of Medical, Pharmaceutical and Health Sciences, Kanazawa University, Kanazawa, Ishikawa, Japan
| | - Junko Sugama
- Department of Gerontological Nursing, Faculty of Nursing, School of Health Sciences, Fujita Health University, Toyoake, Aichi, Japan; Research Center for Implementation Nursing Science Initiative, Innovation Promotion Division, Research Promotion Headquarters, Fujita Health University, Toyoake, Aichi, Japan
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Arnstein T, Buis A. Methodology to Investigate Effect of Prosthetic Interface Design on Residual Limb Soft Tissue Deformation. CANADIAN PROSTHETICS & ORTHOTICS JOURNAL 2024; 6:42196. [PMID: 38873008 PMCID: PMC11168601 DOI: 10.33137/cpoj.v6i1.42196] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2023] [Accepted: 01/10/2024] [Indexed: 06/15/2024] Open
Abstract
BACKGROUND Residual limb discomfort and injury is a common experience for people living with lower limb amputation. Frequently, inadequate load distribution between the prosthetic device and the residual limb is the root cause of this issue. To advance our understanding of prosthetic interface fit, tools are needed to evaluate the mechanical interaction at the prosthetic interface, allowing interface designs to be evaluated and optimised. OBJECTIVE Present a methodology report designed to facilitate comprehension of the mechanical interaction between the prosthetic interface and the residual limb. As a pilot study, this methodology is used to compare a hands-on and hands-off interface for a single transtibial prosthesis user using secondary Magnetic Resonance Imaging (MRI) data. METHODOLOGY MRI data of the residual limb while wearing a prosthetic interface is segmented into a hard tissue and a skin surface model. These models are exported as stereolithography (STL) files. Two methods are used to analyse the interface designs. Firstly, CloudCompare software is used to compute the nearest vertex on the skin surface for every vertex on the compiled internal bony surface for both interface types. Secondly, CloudCompare software is used to compare registered skin surfaces of the residual limb while wearing the hands-on and hands-off interfaces. FINDINGS The maximum and minimum nearest distances between the internal bony surface and skin surface were similar between interface types. However, the distribution of nearest distances was different. When comparing the skin surface while wearing both interfaces, where the fit is more compressive can be visualized. For the dataset used in this study, the classic features of a hands-on Patella Tendon Bearing interface and hands-off pressure cast interface could be identified. CONCLUSION The methodology presented in this report may give researchers a further tool to better understand how interface designs affect the soft tissues of the residual limb.
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Affiliation(s)
- T Arnstein
- Department of Biomedical Engineering, Faculty of Engineering, University of Strathclyde, Glasgow, Scotland
| | - A Buis
- Department of Biomedical Engineering, Faculty of Engineering, University of Strathclyde, Glasgow, Scotland
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Furumasu J, Buckner R, Mata C, Requejo P. OFF-LOADING PRESSURE RELIEF WITH FOAM CUT OUT CUSHIONS: EXPERIENCES FROM RANCHO LOS AMIGOS NATIONAL REHABILITATION CENTER. JOURNAL OF REHABILITATION MEDICINE. CLINICAL COMMUNICATIONS 2023; 6:18706. [PMID: 38025663 PMCID: PMC10658289 DOI: 10.2340/jrmcc.v6.18706] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Accepted: 09/29/2023] [Indexed: 12/01/2023]
Abstract
This paper explores the efficacy of the cushion fitting technique using foam cut out cushions for off-loading bony prominences in the sitting position, with a particular focus on reducing the high risk of developing pressure injuries among aging wheelchair users. This technique, historically employed at Rancho Los Amigos National Rehabilitation Center, has shown promising results in reducing pressure injuries for patients with spinal cord injuries. However, its widespread adoption remains limited. This manuscript aims to raise awareness about foam cut out cushions, its historical context, and its contemporary relevance by presenting customized solutions for individual patients with specific deformities. Key clinical points are highlighted, emphasizing the importance of skilled clinicians in the fitting process and the need to consider foam cut out cushions alongside other preventive measures. Case examples illustrate successful outcomes, demonstrating improved pelvic stability, posture, and off-loading of bony prominences. By promoting foam cut out cushions as a valuable cushioning option, this manuscript equips clinicians with knowledge to utilize this technique effectively.
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Affiliation(s)
- Jan Furumasu
- Department of Physical Therapy, Rancho Los Amigos National Rehabilitation Center
| | - Robyn Buckner
- Department of Physical Therapy, Rancho Los Amigos National Rehabilitation Center
| | - Christine Mata
- Department of Physical Therapy, Rancho Los Amigos National Rehabilitation Center
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He C, Shi P. Interface pressure reduction effects of wheelchair cushions in individuals with spinal cord injury: a rapid review. Disabil Rehabil 2022; 44:827-834. [PMID: 32573289 DOI: 10.1080/09638288.2020.1782487] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/24/2022]
Abstract
OBJECTIVE Wheelchair cushion is routinely used to manage the sitting acquired pressure for an individual with spinal cord injury, but which kind of wheelchair cushion performs better in terms of interface pressure management is unclear. This review aims to compare different kinds of wheelchair cushions on their effect of interface pressure reduction in individuals with spinal cord injury. METHODS AND RESULTS The databases of MEDLINE, CINAHL, EMBASE and Web of Science were searched. Totally 10 studies were included in this review. Seven of the included studies indicated that air cushions were superior to gel cushions in interface pressure reduction. Three of the included studies reported that gel cushions were superior to polyurethane foam cushions in interface pressure reduction. The variables of measurement duration, measurement focus, measurement devices, cushion covering, sample variations and body positioning of patients may confound the comparison of interface pressure reduction effect of different wheelchair cushions among studies. CONCLUSIONS Air cushion was reported more consistently effective in interface pressure reduction than gel and foam cushions. While the variable parameters (measurement duration, focus, devices) and individual conditions (BMI, body positioning) may interfere the comparison among studies. Researches disseminating consistent parameters and clinical prescriptions with individualized evaluation are suggested for the establishment of an evidence-based practice in clinic.Implications for rehabilitationWheelchair cushion is routinely used for an individual post spinal cord injury to manage the sitting acquired pressure.Which kind of wheelchair cushion performs better in terms of interface pressure management is unclear.Air cushion is found more consistently effective in interface pressure reduction than gel cushion and foam cushion.Individualized evaluation of the interface pressure is suggested for the prescription of wheelchair cushion in clinic.
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Affiliation(s)
- Chen He
- Institute of Rehabilitation Engineering and Technology, University of Shanghai for Science and Technology, Shanghai, China
| | - Ping Shi
- Institute of Rehabilitation Engineering and Technology, University of Shanghai for Science and Technology, Shanghai, China
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Damiao J, Gentry T. A systematic review of the effectiveness of pressure relieving cushions in reducing pressure injury. Assist Technol 2022:1-5. [PMID: 34813723 DOI: 10.1080/10400435.2021.2010148] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 11/11/2021] [Indexed: 10/19/2022] Open
Abstract
This systematic review seeks to gather and analyze the evidence on wheelchair pressure relieving cushions, and report on the optimal materials and designs for reducing pressure injury risk. The following research question guides this study: Which wheelchair cushions best reduce pressure injury risk? PIs continue to impact the health and function of wheelchairs users with significant mobility impairments. Pressure relieving cushions are typically prescribed to provide pressure relief in the pre-wound, wound, and post-wound phases. Presently, no published reviews analyze all of the commonly available cushion materials. Most comparison studies typically address a specific population such as spinal cord injury, or only a few styles of cushion design/materials. Results suggest air-cell cushions provide optimal pressure relief and shear reduction. Furthermore, small sample single cohort studies suggest off-loading cushions provide superior pressure relief beyond that of air-celled cushions but require additional research for greater generalizability.
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Affiliation(s)
- John Damiao
- Occupational Therapy Department, Pace University, New York, New York, USA
| | - Tony Gentry
- Occupational Therapy Department, Virginia Commonwealth University, Richmond, Virginia, USA
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8
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Custom-contoured seating from unloaded shape capture: A pilot study. J Tissue Viability 2022; 31:255-258. [DOI: 10.1016/j.jtv.2022.01.005] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2021] [Revised: 01/18/2022] [Accepted: 01/19/2022] [Indexed: 11/21/2022]
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Kim DG, Park ES, Nam SM, Cha HG, Choi CY. Volumetric Evaluation of Dead Space in Ischial Pressure Injuries Using Magnetic Resonance Imaging: A Case Series. Adv Skin Wound Care 2021; 34:668-673. [PMID: 34807898 DOI: 10.1097/01.asw.0000797960.52759.75] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
OBJECTIVE To establish a preoperative evaluation procedure by measuring the volume of dead space using MRI in patients with ischial pressure injuries. METHODS Patients with spinal cord injury and ischial pressure injuries who underwent treatment between August 2016 and November 2019 were included in the study. Preoperative MRI scan was conducted on all patients. The volume estimation and three-dimensional (3D) reconstruction were performed based on MRI data using a 3D Slicer. Based on the resulting volume, a muscle flap that could fit the dead space was selected. Surgery was performed with the selected muscle flap, and a fasciocutaneous flap was added, if necessary. RESULTS A total of eight patients with ischial pressure injuries were included in the study. The mean patient age was 59.0 ± 11.0 years. The mean body mass index was 26.62 ± 3.89 kg/m2. The mean volume of dead space was 104.75 ± 81.05 cm3. The gracilis muscle was the most selected muscle flap and was used in four patients. In five of eight cases, a fasciocutaneous flap was used as well. The mean follow-up period was 16 months, and by that point, none of the patients evinced complications that required surgery. CONCLUSIONS To the authors' knowledge, this is the first report on volumetric evaluation of dead space in ischial pressure injuries. The authors believe that the 3D reconstruction process would enable adequate dead space obliteration in ischial pressure injuries. The authors propose that preoperative MRI scans in patients with ischial pressure injury should become an essential part of the process.
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Affiliation(s)
- Dong Gyu Kim
- In the Department of Plastic and Reconstructive Surgery at the Soonchunhyang University Bucheon Hospital in Bucheon, Republic of Korea, Dong Gyu Kim, MD, is Resident; Eun Soo Park, MD, PhD, is Professor and Chief of the Medical Department; Seung Min Nam, MD, PhD, and Chang Yong Choi, MD, PhD are Associate Professors; and Han Gyu Cha, MD, is Assistant Professor. Acknowledgments : This work was supported by the Soonchunhyang University Research Fund. The authors have disclosed no other financial relationships related to this article. Submitted October 16, 2020; accepted in revised form January 26, 2021
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Kobara K, Nagata Y, Fujita D, Takahashi H, Osaka H, Suehiro T. Investigation of the effect of a 15-degree tilt-in-space on the fluctuation of shear forces exerted on the buttocks when the back support is reclined. J Phys Ther Sci 2021; 33:838-844. [PMID: 34776619 PMCID: PMC8575471 DOI: 10.1589/jpts.33.838] [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] [Received: 06/30/2021] [Accepted: 08/02/2021] [Indexed: 11/24/2022] Open
Abstract
[Purpose] This study aimed to investigate the effect of the combination of 15° tilt-in-space and recline angles on the fluctuation of shear forces exerted on the buttocks. [Participants and Methods] The participants were 11 healthy adult males. The parameters of the shear forces were the parallel and perpendicular forces exerted on the buttocks as measured by a force plate. The two conditions tested were T0R100-130 and T15R100-130. The tilt-in-space angles were set to 0° and 15° in the T0R100-130 and T15R100-130 conditions, respectively. The reclining angles were determined to be 100° to 130° in both conditions. [Results] Upon comparing the two conditions, the parallel and the perpendicular forces exerted on the buttocks in the T15R100-130 condition were significantly lower than those in the T0R100-130 condition in all positions of back support. Upon comparing the fluctuation values of the parallel and perpendicular forces, those applied in the T15R100-130 condition were significantly higher than those in the T0R100-130 condition. [Conclusion] These results suggest that the fluctuation of shear forces exerted on the buttocks could be decreased by using a combination of 15° tilt-in-space and reclining functions.
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Affiliation(s)
- Kenichi Kobara
- Department of Physical Therapy, Faculty of Rehabilitation, Kawasaki University of Medical Welfare: 288 Matsushima, Kurashiki, Okayama 701-0193, Japan
| | - Yasuyuki Nagata
- Department of Physical Therapy, Faculty of Rehabilitation, Kawasaki University of Medical Welfare: 288 Matsushima, Kurashiki, Okayama 701-0193, Japan
| | - Daisuke Fujita
- Department of Physical Therapy, Faculty of Rehabilitation, Kawasaki University of Medical Welfare: 288 Matsushima, Kurashiki, Okayama 701-0193, Japan
| | - Hisashi Takahashi
- Department of Physical Therapy, Faculty of Rehabilitation, Kawasaki University of Medical Welfare: 288 Matsushima, Kurashiki, Okayama 701-0193, Japan
| | - Hiroshi Osaka
- Department of Physical Therapy, Faculty of Rehabilitation, Kawasaki University of Medical Welfare: 288 Matsushima, Kurashiki, Okayama 701-0193, Japan
| | - Tadanobu Suehiro
- Department of Physical Therapy, Faculty of Rehabilitation, Kawasaki University of Medical Welfare: 288 Matsushima, Kurashiki, Okayama 701-0193, Japan
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Wang X, Savonnet L, Capbern L, Duprey S. A Case Study on the Effects of Foam and Seat Pan Inclination on the Deformation of Seated Buttocks Using MRI. IISE Trans Occup Ergon Hum Factors 2021. [PMID: 34569437 DOI: 10.1080/24725838.2021.1984340] [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] [Indexed: 10/18/2022]
Abstract
OCCUPATIONAL APPLICATIONSWe investigated the effects of seat pan inclination and foam on the deformation of the seated buttocks using an upright MRI system. From observations among four healthy males, we found that soft tissue deformation under the ischial tuberosity (IT) could be reduced not only by using a soft cushion, but also by decreasing the shear force on the seat pan surface. These results suggest that soft tissue deformation could be used as an objective measure for assessing seating discomfort and injury risk, by accounting for the effects of both contact pressure and shear. We also confirmed that the gluteus maximus (GM) muscle displaced away from the IT once seated. As peak pressure and shear are most likely located below the IT, more realistic computational human body models in this region are needed that consider muscle sliding.
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Affiliation(s)
- Xuguang Wang
- Univ-Lyon, Université Claude Bernard Lyon1, Université Gustave Eiffel, LBMC UMR_T9406, F69622, Lyon, France
| | - Léo Savonnet
- Univ-Lyon, Université Claude Bernard Lyon1, Université Gustave Eiffel, LBMC UMR_T9406, F69622, Lyon, France
| | - Loïc Capbern
- Univ-Lyon, Université Claude Bernard Lyon1, Université Gustave Eiffel, LBMC UMR_T9406, F69622, Lyon, France
| | - Sonia Duprey
- Univ-Lyon, Université Claude Bernard Lyon1, Université Gustave Eiffel, LBMC UMR_T9406, F69622, Lyon, France
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JANG WANHO, LEE SEUNGBOK, CHOI WONSEUK, KIM JONGBAE. A STUDY OF PRESSURE DISTRIBUTION EFFECT AND USER SATISFACTION OF A CUSTOMIZED OFF-LOADING CUSHION BASED ON 3D MODELING: A COMPARISON WITH CONVENTIONAL AIR CUSHIONS. J MECH MED BIOL 2020. [DOI: 10.1142/s0219519420400357] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
The study was to compare an off-loading cushion, designed for individuals with spinal cord injury, with air cushion to analyze the effect of pressure on skin injury and user satisfaction. The off-loading cushion can reduce the incidence of pressure ulcers by minimizing the pressure of the ischial tuberosity and coccyx. Because anatomical structures of each participant are different, 3D scanning is used in the customized manufacturing of the cushions. In the 3D modeling, the product is designed so that the ischial tuberosity and coccyx have minimal contact with the cushion’s surface area. The X-sensor was used to confirm the pressure dispersion effect. As a result, maximum pressure of the ischial tuberosity and the coccyx were measured and observed to be lower than that of the air cushion. User satisfaction was compared between two cushions using the QUEST 2.0. The off-loading cushion has slightly higher service and product satisfaction than the air cushion. Based on these findings, this study suggests that off-loading cushions reduce the occurrence of pressure injury compared to air cushions.
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Affiliation(s)
- WAN-HO JANG
- Corporate Research Institute, Wheelopia Co., Ltd, Seoul 07053, Republic of Korea
| | - SEUNG-BOK LEE
- Clinical Team, Yonsei Enabling Science and Technology Research Center, Wonju 26493, Republic of Korea
| | - WON-SEUK CHOI
- Department of Clinical Rehabilitation Research, Korea National Rehabilitation Center, Seoul 01022, Republic of Korea
| | - JONG-BAE KIM
- Department of Occupational Therapy, College of Health Science, Yonsei University, Wonju 26493, Republic of Korea
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JANG WANHO, LEE SEUNGBOK, CHOI WONSEUK, KIM JONGBAE. A STUDY OF PRESSURE DISTRIBUTION EFFECT AND USER SATISFACTION OF A CUSTOMIZED OFF-LOADING CUSHION BASED ON 3D MODELING: A COMPARISON WITH CONVENTIONAL AIR CUSHIONS. J MECH MED BIOL 2020; 20:2040035. [DOI: https:/doi.org/10.1142/s0219519420400357] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 09/04/2023]
Abstract
The study was to compare an off-loading cushion, designed for individuals with spinal cord injury, with air cushion to analyze the effect of pressure on skin injury and user satisfaction. The off-loading cushion can reduce the incidence of pressure ulcers by minimizing the pressure of the ischial tuberosity and coccyx. Because anatomical structures of each participant are different, 3D scanning is used in the customized manufacturing of the cushions. In the 3D modeling, the product is designed so that the ischial tuberosity and coccyx have minimal contact with the cushion’s surface area. The X-sensor was used to confirm the pressure dispersion effect. As a result, maximum pressure of the ischial tuberosity and the coccyx were measured and observed to be lower than that of the air cushion. User satisfaction was compared between two cushions using the QUEST 2.0. The off-loading cushion has slightly higher service and product satisfaction than the air cushion. Based on these findings, this study suggests that off-loading cushions reduce the occurrence of pressure injury compared to air cushions.
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Affiliation(s)
- WAN-HO JANG
- Corporate Research Institute, Wheelopia Co., Ltd, Seoul 07053, Republic of Korea
| | - SEUNG-BOK LEE
- Clinical Team, Yonsei Enabling Science and Technology Research Center, Wonju 26493, Republic of Korea
| | - WON-SEUK CHOI
- Department of Clinical Rehabilitation Research, Korea National Rehabilitation Center, Seoul 01022, Republic of Korea
| | - JONG-BAE KIM
- Department of Occupational Therapy, College of Health Science, Yonsei University, Wonju 26493, Republic of Korea
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14
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Liu Z, Cascioli V, McCarthy PW. Review of Measuring Microenvironmental Changes at the Body-Seat Interface and the Relationship between Object Measurement and Subjective Evaluation. SENSORS 2020; 20:s20236715. [PMID: 33255342 PMCID: PMC7727653 DOI: 10.3390/s20236715] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 10/21/2020] [Revised: 11/13/2020] [Accepted: 11/20/2020] [Indexed: 12/11/2022]
Abstract
Being seated has increasingly pervaded both working and leisure lifestyles, with development of more comfortable seating surfaces dependent on feedback from subjective questionnaires and design aesthetics. As a consequence, research has become focused on how to objectively resolve factors that might underpin comfort and discomfort. This review summarizes objective methods of measuring the microenvironmental changes at the body–seat interface and examines the relationship between objective measurement and subjective sensation. From the perspective of physical parameters, pressure detection accounted for nearly two thirds (37/54) of the publications, followed by microclimatic information (temperature and relative humidity: 18/54): it is to be noted that one article included both microclimate and pressure measurements and was placed into both categories. In fact, accumulated temperature and relative humidity at the body–seat interface have similarly negative effects on prolonged sitting to that of unrelieved pressure. Another interesting finding was the correlation between objective measurement and subjective evaluation; however, the validity of this may be called into question because of the differences in experiment design between studies.
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Affiliation(s)
- Zhuofu Liu
- The Higher Educational Key Laboratory for Measuring and Control Technology and Instrumentations of Heilongjiang Province, Harbin University of Science and Technology, Harbin 150080, China
- Correspondence: ; Tel.: +86-139-0451-2205
| | - Vincenzo Cascioli
- Murdoch University Chiropractic Clinic, Murdoch University, Murdoch 6150, Australia;
| | - Peter W. McCarthy
- Faculty of Life Science and Education, University of South Wales, Treforest, Pontypridd CF37 1DL, UK;
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15
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Sonenblum SE, Seol D, Sprigle SH, Cathcart JM. Seated buttocks anatomy and its impact on biomechanical risk. J Tissue Viability 2020; 29:69-75. [PMID: 32008891 DOI: 10.1016/j.jtv.2020.01.004] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/27/2019] [Revised: 01/13/2020] [Accepted: 01/20/2020] [Indexed: 11/28/2022]
Abstract
AIM The objective of this study was to describe the amount, types, and shapes of tissue present in the buttocks during sitting (i.e., seated buttocks soft tissue anatomy), and the impact of seated buttocks soft tissue anatomy on biomechanical risk. MATERIALS AND METHODS The buttocks of 35 people, including 29 full-time wheelchair users with and without a history of pelvic pressure ulcers were scanned sitting upright on 3" of flat HR45 foam in a FONAR Upright MRI. Multi-planar scans were analyzed to calculate bulk tissue thickness, tissue composition, gluteus maximus coverage at the ischium, the contour of the skin, and pelvic tilt. RESULTS Bulk tissue thickness varied from 5.6 to 32.1 mm, was composed mostly of adipose tissue, and was greatest in the able-bodied cohort. Skin contours varied significantly across status group, with wheelchair users with a history of pressure ulcers having tissue with a peaked contour with a radius of curvature of 65.9 mm that wrapped more closely to the ischium (thickness at the apex = 8.2 mm) as compared to wheelchair users with no pressure ulcer history (radius of curvature = 91.5 mm and apex thickness = 14.5 mm). Finally, the majority of participants presented with little to no gluteus coverage over their ischial tuberosity, regardless of status group. CONCLUSIONS This study provides quantitative evidence that Biomechanical Risk, or the intrinsic characteristic of an individual's soft tissues to deform in response to extrinsic applied forces, is greater in individuals at greater risk for pressure ulcers.
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Affiliation(s)
- Sharon E Sonenblum
- Rehabilitation Engineering and Applied Research Laboratory, The George W. Woodruff School of Mechanical Engineering, Georgia Institute of Technology, 801 Atlantic Dr. Office 026, Atlanta, Georgia.
| | - Davin Seol
- Rehabilitation Engineering and Applied Research Laboratory, The George W. Woodruff School of Mechanical Engineering, Georgia Institute of Technology, 801 Atlantic Dr. Office 026, Atlanta, Georgia.
| | - Stephen H Sprigle
- Rehabilitation Engineering and Applied Research Laboratory, College of Design and The George W. Woodruff School of Mechanical Engineering, Georgia Institute of Technology, 801 Atlantic Dr., Lab 027, Atlanta, Georgia.
| | - John McKay Cathcart
- Lecturer in Diagnostic Radiography, Room 17J10, School of Health Sciences Ulster University, Shore Road, Jordanstown, Newtownabbey, Antrim, Ireland.
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Macron A, Pillet H, Doridam J, Rivals I, Sadeghinia MJ, Verney A, Rohan PY. Is a simplified Finite Element model of the gluteus region able to capture the mechanical response of the internal soft tissues under compression? Clin Biomech (Bristol, Avon) 2020; 71:92-100. [PMID: 31707190 DOI: 10.1016/j.clinbiomech.2019.10.005] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/26/2019] [Revised: 09/11/2019] [Accepted: 10/02/2019] [Indexed: 02/07/2023]
Abstract
BACKGROUND Internal soft tissue strains have been shown to be one of the main factors responsible for the onset of Pressure Ulcers and to be representative of its risk of development. However, the estimation of this parameter using Finite Element (FE) analysis in clinical setups is currently hindered by costly acquisition, reconstruction and computation times. Ultrasound (US) imaging is a promising candidate for the clinical assessment of both morphological and material parameters. METHOD The aim of this study was to investigate the ability of a local FE model of the region beneath the ischium with a limited number of parameters to capture the internal response of the gluteus region predicted by a complete 3D FE model. 26 local FE models were developed, and their predictions were compared to those of the patient-specific reference FE models in sitting position. FINDINGS A high correlation was observed (R = 0.90, p-value < 0.01). A sensitivity analysis showed that the most influent parameters were the mechanical behaviour of the muscle tissues, the ischium morphology and the external mechanical loading. INTERPRETATION Given the progress of US for capturing both morphological and material parameters, these results are promising because they open up the possibility to use personalised simplified FE models for risk estimation in daily clinical routine.
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Affiliation(s)
- Aurélien Macron
- Institut de Biomécanique Humaine Georges Charpak, Arts et Métiers ParisTech, 151 bd de l'Hôpital, 75013 Paris, France; Univ. Grenoble Alpes, CEA, LETI, CLINATEC, MINATEC Campus, 38000 Grenoble, France
| | - Hélène Pillet
- Institut de Biomécanique Humaine Georges Charpak, Arts et Métiers ParisTech, 151 bd de l'Hôpital, 75013 Paris, France
| | - Jennifer Doridam
- Institut de Biomécanique Humaine Georges Charpak, Arts et Métiers ParisTech, 151 bd de l'Hôpital, 75013 Paris, France
| | - Isabelle Rivals
- Sorbonne Université, INSERM, UMRS1158 Neurophysiologie Respiratoire Expérimentale et Clinique, Paris, France; Equipe de Statistique Appliquée, ESPCI Paris, PSL Research University, Paris, France
| | - Mohammad Javad Sadeghinia
- Institut de Biomécanique Humaine Georges Charpak, Arts et Métiers ParisTech, 151 bd de l'Hôpital, 75013 Paris, France; School of Mechanical Engineering, College of Engineering, University of Tehran, Tehran, Iran
| | - Alexandre Verney
- CEA, LIST, Interactive Robotics Laboratory, F-91191 Gif-sur-Yvette, France
| | - Pierre-Yves Rohan
- Institut de Biomécanique Humaine Georges Charpak, Arts et Métiers ParisTech, 151 bd de l'Hôpital, 75013 Paris, France.
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17
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Investigation of effects of urethane foam mattress hardness on skin and soft tissue deformation in the prone position using magnetic resonance imaging. J Tissue Viability 2019; 28:14-20. [DOI: 10.1016/j.jtv.2018.10.007] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2018] [Revised: 10/26/2018] [Accepted: 10/27/2018] [Indexed: 12/13/2022]
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Macron A, Pillet H, Doridam J, Verney A, Rohan PY. Development and evaluation of a new methodology for the fast generation of patient-specific Finite Element models of the buttock for sitting-acquired deep tissue injury prevention. J Biomech 2018; 79:173-180. [PMID: 30201252 DOI: 10.1016/j.jbiomech.2018.08.001] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2017] [Revised: 06/17/2018] [Accepted: 08/10/2018] [Indexed: 01/11/2023]
Abstract
The occurrence and management of Pressure Ulcers remain a major issue for patients with reduced mobility and neurosensory loss despite significant improvement in the prevention methods. These injuries are caused by biological cascades leading from a given mechanical loading state in tissues to irreversible tissue damage. Estimating the internal mechanical conditions within loaded soft tissues has the potential of improving the management and prevention of PU. Several Finite Element models of the buttock have therefore been proposed based on either MRI or CT-Scan data. However, because of the limited availability of MRI or CT-Scan systems and of the long segmentation time, all studies in the literature include the data of only one individual. Yet the inter-individual variability can't be overlooked when dealing with patient specific estimation of internal tissue loading. As an alternative, this contribution focuses on the combined use of low-dose biplanar X-ray images, B-mode ultrasound images and optical scanner acquisitions in a non-weight-bearing sitting posture for the fast generation of patient-specific FE models of the buttock. Model calibration was performed based on Ischial Tuberosity sagging. Model evaluation was performed by comparing the simulated contact pressure with experimental observations on a population of 6 healthy subjects. Analysis of the models confirmed the high inter-individual variability of soft tissue response (maximum Green Lagrange shear strains of 213 ± 101% in the muscle). This methodology opens the way for investigating inter-individual factors influencing the soft tissue response during sitting and for providing tools to assess PU risk.
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Affiliation(s)
- Aurélien Macron
- Institut de Biomécanique Humaine Georges Charpak, Arts et Métiers ParisTech, 151 bd de l'Hôpital, 75013 Paris, France; Univ. Grenoble Alpes, CEA, LETI, CLINATEC, MINATEC Campus, 38000 Grenoble, France.
| | - Hélène Pillet
- Institut de Biomécanique Humaine Georges Charpak, Arts et Métiers ParisTech, 151 bd de l'Hôpital, 75013 Paris, France
| | - Jennifer Doridam
- Institut de Biomécanique Humaine Georges Charpak, Arts et Métiers ParisTech, 151 bd de l'Hôpital, 75013 Paris, France
| | - Alexandre Verney
- CEA, LIST, Interactive Robotics Laboratory, F-91191 Gif-sur-Yvette, France
| | - Pierre-Yves Rohan
- Institut de Biomécanique Humaine Georges Charpak, Arts et Métiers ParisTech, 151 bd de l'Hôpital, 75013 Paris, France
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Doridam J, Macron A, Vergari C, Verney A, Rohan PY, Pillet H. Feasibility of sub-dermal soft tissue deformation assessment using B-mode ultrasound for pressure ulcer prevention. J Tissue Viability 2018; 27:238-243. [PMID: 30195464 DOI: 10.1016/j.jtv.2018.08.002] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/19/2018] [Revised: 07/15/2018] [Accepted: 08/10/2018] [Indexed: 10/28/2022]
Abstract
Pressure Ulcer (PU) prevention remains a main public health issue. The physio-pathology of this injury is not fully understood, and a satisfactory therapy is currently not available. Recently, several works suggested that mechanical strains are responsible of deformation-induced damage involved in the initiation of Deep Tissue Injury (DTI). A better assessment of the internal behavior could allow to enhance the modeling of the transmission of loads into the different structures composing the buttock. A few studies focused on the experimental in vivo buttock deformation quantification using Magnetic Resonance Imaging (MRI), but its use has important drawbacks. In clinical practice, ultrasound imaging is an accessible, low cost, and real-time technic to study the soft tissue. The objective of the present work was to show the feasibility of using B-mode ultrasound imaging for the quantification of localised soft-tissue strains of buttock tissues during sitting. An original protocol was designed, and the intra-operator reliability of the method was assessed. Digital Image Correlation was used to compute the displacement field of the soft tissue of the buttock during a full realistic loading while sitting. Reference data of the strains in the frontal and sagittal planes under the ischium were reported for a population of 7 healthy subjects. The average of shear strains over the region of interest in the fat layer reached levels up to 117% higher than the damage thresholds previously quantified for the muscular tissue in rats. In addition, the observation of the muscles displacements seems to confirm previous results which already reported the absence of muscular tissue under the ischium in the seated position, questioning the assumption commonly made in Finite Element modeling that deep tissue injury initiates in the muscle underlying the bone.
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Affiliation(s)
- J Doridam
- Arts et Métiers ParisTech, LBM/Institut de Biomécanique Humaine Georges Charpak, 151 bd de l'Hôpital, 75013, Paris, France; Department of Anatomy, University Paris XIII, UFR Santé Médecine Biologie Humaine, Bobigny, France.
| | - A Macron
- Arts et Métiers ParisTech, LBM/Institut de Biomécanique Humaine Georges Charpak, 151 bd de l'Hôpital, 75013, Paris, France; CEA, LIST, Interactive Robotics Laboratory, F-91191, Gif-sur-Yvette, France
| | - C Vergari
- Arts et Métiers ParisTech, LBM/Institut de Biomécanique Humaine Georges Charpak, 151 bd de l'Hôpital, 75013, Paris, France
| | - A Verney
- CEA, LIST, Interactive Robotics Laboratory, F-91191, Gif-sur-Yvette, France
| | - P-Y Rohan
- Arts et Métiers ParisTech, LBM/Institut de Biomécanique Humaine Georges Charpak, 151 bd de l'Hôpital, 75013, Paris, France
| | - H Pillet
- Arts et Métiers ParisTech, LBM/Institut de Biomécanique Humaine Georges Charpak, 151 bd de l'Hôpital, 75013, Paris, France
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Budai M, Farrell E, Michael E. Manual Wheelchair Configuration and Seating Considerations in the Spinal Cord Injury Population. CURRENT PHYSICAL MEDICINE AND REHABILITATION REPORTS 2018. [DOI: 10.1007/s40141-018-0195-8] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
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21
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Sonenblum SE, Ma J, Sprigle SH, Hetzel TR, McKay Cathcart J. Measuring the impact of cushion design on buttocks tissue deformation: An MRI approach. J Tissue Viability 2018; 27:162-172. [DOI: 10.1016/j.jtv.2018.04.001] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2017] [Revised: 04/06/2018] [Accepted: 04/23/2018] [Indexed: 12/17/2022]
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22
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Bader DL, Worsley PR. Technologies to monitor the health of loaded skin tissues. Biomed Eng Online 2018; 17:40. [PMID: 29650012 PMCID: PMC5897925 DOI: 10.1186/s12938-018-0470-z] [Citation(s) in RCA: 52] [Impact Index Per Article: 8.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/06/2017] [Accepted: 03/24/2018] [Indexed: 01/18/2023] Open
Abstract
There are many situations where the skin and underlying soft tissues are compromised by mechanical loading in the form or pressure, or pressure in combination with shear. If sustained, this can lead to damage in the tissues particularly adjacent to bony prominences, resulting in chronic wounds. An array of bioengineering technologies have been adopted to assess the integrity of loaded soft tissues. This paper aims to review these approaches for the quantification, simulation and early detection of mechanically-induced skin damage. The review considers different measurements at the interface between the skin and support surface/medical device, involving pressure, shear, friction and the local microclimate. The potential of the techniques to monitor the physiological response of the skin to these external stimuli including biophysical measurement devices and sampling of biofluids are critically analysed. In addition, it includes an analysis of medical imaging technologies and computational modelling to provide a means by which tissue deformation can be quantified and thresholds for tissue damage defined. Bioengineering measurement and imaging technologies have provided an insight into the temporal status of loaded skin. Despite the advances in technology, to date, the translation to clinical tools which are robust and cost effective has been limited. There is a need to adapt existing technologies and simulation platforms to enable patients, carers and clinicians to employ appropriate intervention strategies to minimise soft tissue damage.
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Affiliation(s)
- Dan L Bader
- Skin Health Group, Faculty of Health Sciences, University of Southampton, Southampton General Hospital, Tremona Road, Southampton, SO16 6YD, UK.
| | - Peter R Worsley
- Skin Health Group, Faculty of Health Sciences, University of Southampton, Southampton General Hospital, Tremona Road, Southampton, SO16 6YD, UK.
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Al-Dirini RMA, Nisyrios J, Reed MP, Thewlis D. Quantifying the in vivo quasi-static response to loading of sub-dermal tissues in the human buttock using magnetic resonance imaging. Clin Biomech (Bristol, Avon) 2017; 50:70-77. [PMID: 28987874 DOI: 10.1016/j.clinbiomech.2017.09.017] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/17/2016] [Revised: 09/25/2017] [Accepted: 09/27/2017] [Indexed: 02/07/2023]
Abstract
BACKGROUND The design of seating systems to improve comfort and reduce injury would benefit from improved understanding of the deformation and strain patterns in soft tissues, particularly in the gluteal region. METHODS Ten healthy men were positioned in a semi-recumbent posture while their pelvic and thigh region was scanned using a wide-bore magnetic resonance imaging (MRI) scanner. Independent measurements of deformation for muscles and fat were taken for the transition from non-weight-bearing to weight-bearing loads in three stages. A weight-bearing load was achieved through having the subject supported by a flat, rigid surface. A non-weight-bearing condition was achieved by removing the support under the left buttock, leaving all soft tissue layers undeformed. An intermediate condition partially relieved the subject's left buttock by lowering the support relative to the pelvis by 20mm, which left the buttock partially deformed. For each of these conditions, the thicknesses of muscle and fat tissues below the ischial tuberosity and the greater trochanter were measured from the MRI data. FINDINGS In this dataset, the greatest soft tissue deformation took place below the ischial tuberosity, with muscles (mean=17.7mm, SD=4.8mm) deforming more than fat tissues (mean=4.3mm, SD=5.6mm). Muscles deformed through both steps of the transition from weight-bearing to non-weight-bearing conditions, while subcutaneous fat deformed little after the first transition from non-weight-bearing to partial-weight-bearing. High inter-subject variability in muscle and fat tissue strains was observed. INTERPRETATION Our findings highlight the importance of considering inter-subject variability when designing seating systems.
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Affiliation(s)
- Rami M A Al-Dirini
- Medical Devices Research Institute, College of Science and Engineering, Flinders University, Adelaide, SA 5001, Australia.
| | - John Nisyrios
- Fowler Simmons Radiology, Adelaide, SA 5000, Australia
| | - Matthew P Reed
- University of Michigan Transportation Research Institute, University of Michigan, Ann Arbor, MI 48109, USA
| | - Dominic Thewlis
- Centre for Orthopaedic & Trauma Research, Faculty of Health and Medical Sciences, The University of Adelaide, Adelaide, SA 5000, Australia
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