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Shi Y, Wu X, Paydarfar JA, Halter RJ. An Imaging-Compatible Oral Retractor System for Transoral Robotic Surgery. Ann Biomed Eng 2024:10.1007/s10439-024-03536-7. [PMID: 38796669 DOI: 10.1007/s10439-024-03536-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/20/2023] [Accepted: 05/02/2024] [Indexed: 05/28/2024]
Abstract
This study aimed to develop and validate a Computed Tomography (CT)/Magnetic Resonance Imaging (MRI)-compatible polymer oral retractor system to enable intraoperative image guidance for transoral robotic surgery (TORS). The retractor was designed based on standard-of-care metallic retractors and 3D (three-dimensional) printed with carbon fiber composite and nylon. The system was comprehensively evaluated in bench-top and cadaveric experiments in terms of its ability to enable intraoperative CT/MR images during TORS, functionality including surgical exposure and working volume, usability, compatibility with da Vinci surgical systems, feasibility for disinfection or sterilization, and robustness over an extended period of time. The polymer retractor system enabled the acquisition of high-resolution and artifact-free intraoperative CT/MR images during TORS. With an inter-incisive distance of 42.55 mm and a working volume of 200.09 cm3, it provided surgical exposure comparable to standard-of-care metallic retractors. The system proved intuitive and compatible with da Vinci S, Xi, and Single Port systems, enabling successful mock surgical tasks performed by surgeons and residents. The retractor components could be effectively disinfected or sterilized for clinical use without significant compromise in material strength, with STERRAD considered the optimal method. Throughout a 2 h mock procedure, the retractor system showed minimal displacements (<1.5 mm) due to surrounding tissue deformation, with insignificant device deformation. The 3D-printed polymer retractor system successfully enabled artifact-free intraoperative CT/MR imaging in TORS for the first time and demonstrated feasibility for clinical use. This breakthrough opens the door to surgical navigation with intraoperative image guidance in TORS, offering the potential to significantly improve surgical outcomes and patients' quality of life.
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Affiliation(s)
- Yuan Shi
- Thayer School of Engineering, Dartmouth College, Hanover, NH, USA.
| | - Xiaotian Wu
- Thayer School of Engineering, Dartmouth College, Hanover, NH, USA
| | - Joseph A Paydarfar
- Thayer School of Engineering, Dartmouth College, Hanover, NH, USA
- Section of Otolaryngology, Audiology, and Maxillofacial Surgery, Department of Surgery, Dartmouth-Hitchcock Medical Center, Lebanon, NH, USA
- Geisel School of Medicine, Dartmouth College, Hanover, NH, USA
| | - Ryan J Halter
- Thayer School of Engineering, Dartmouth College, Hanover, NH, USA
- Geisel School of Medicine, Dartmouth College, Hanover, NH, USA
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2
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Durcan C, Hossain M, Chagnon G, Perić D, Girard E. Mechanical experimentation of the gastrointestinal tract: a systematic review. Biomech Model Mechanobiol 2024; 23:23-59. [PMID: 37935880 PMCID: PMC10901955 DOI: 10.1007/s10237-023-01773-8] [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: 03/28/2023] [Accepted: 09/10/2023] [Indexed: 11/09/2023]
Abstract
The gastrointestinal (GI) organs of the human body are responsible for transporting and extracting nutrients from food and drink, as well as excreting solid waste. Biomechanical experimentation of the GI organs provides insight into the mechanisms involved in their normal physiological functions, as well as understanding of how diseases can cause disruption to these. Additionally, experimental findings form the basis of all finite element (FE) modelling of these organs, which have a wide array of applications within medicine and engineering. This systematic review summarises the experimental studies that are currently in the literature (n = 247) and outlines the areas in which experimentation is lacking, highlighting what is still required in order to more fully understand the mechanical behaviour of the GI organs. These include (i) more human data, allowing for more accurate modelling for applications within medicine, (ii) an increase in time-dependent studies, and (iii) more sophisticated in vivo testing methods which allow for both the layer- and direction-dependent characterisation of the GI organs. The findings of this review can also be used to identify experimental data for the readers' own constitutive or FE modelling as the experimental studies have been grouped in terms of organ (oesophagus, stomach, small intestine, large intestine or rectum), test condition (ex vivo or in vivo), number of directions studied (isotropic or anisotropic), species family (human, porcine, feline etc.), tissue condition (intact wall or layer-dependent) and the type of test performed (biaxial tension, inflation-extension, distension (pressure-diameter), etc.). Furthermore, the studies that investigated the time-dependent (viscoelastic) behaviour of the tissues have been presented.
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Affiliation(s)
- Ciara Durcan
- Zienkiewicz Centre for Modelling, Data and AI, Faculty of Science and Engineering, Swansea University, Swansea, SA1 8EN, UK
- Université Grenoble Alpes, CNRS, UMR 5525, VetAgro Sup, Grenoble INP, TIMC, 38000, Grenoble, France
| | - Mokarram Hossain
- Zienkiewicz Centre for Modelling, Data and AI, Faculty of Science and Engineering, Swansea University, Swansea, SA1 8EN, UK.
| | - Grégory Chagnon
- Université Grenoble Alpes, CNRS, UMR 5525, VetAgro Sup, Grenoble INP, TIMC, 38000, Grenoble, France
| | - Djordje Perić
- Zienkiewicz Centre for Modelling, Data and AI, Faculty of Science and Engineering, Swansea University, Swansea, SA1 8EN, UK
| | - Edouard Girard
- Université Grenoble Alpes, CNRS, UMR 5525, VetAgro Sup, Grenoble INP, TIMC, 38000, Grenoble, France
- Laboratoire d'Anatomie des Alpes Françaises, Université Grenoble Alpes, Grenoble, France
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3
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Gong AT, Yau SWO, Erickson HB, Toepfer RJ, Zhang J, Deschmidt AM, Parsey CJ, Norfleet JE, Sweet RM. Characterizing the Suture Pullout Force for Human Small Bowel. J Biomech Eng 2024; 146:014502. [PMID: 37916891 DOI: 10.1115/1.4063951] [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: 06/09/2023] [Accepted: 09/25/2023] [Indexed: 11/03/2023]
Abstract
Performing a small bowel anastomosis, or reconnecting small bowel segments, remains a core competency and critical step for the successful surgical management of numerous bowel and urinary conditions. As surgical education and technology moves toward improving patient outcomes through automation and increasing training opportunities, a detailed characterization of the interventional biomechanical properties of the human bowel is important. This is especially true due to the prevalence of anastomotic leakage as a frequent (3.02%) postoperative complication of small bowel anastomoses. This study aims to characterize the forces required for a suture to tear through human small bowel (suture pullout force, SPOF), while analyzing how these forces are affected by tissue orientation, suture material, suture size, and donor demographics. 803 tests were performed on 35 human small bowel specimens. A uni-axial test frame was used to tension sutures looped through 10 × 20 mm rectangular bowel samples to tissue failure. The mean SPOF of the small bowel was 4.62±1.40 N. We found no significant effect of tissue orientation (p = 0.083), suture material (p = 0.681), suture size (p = 0.131), age (p = 0.158), sex (p = .083), or body mass index (BMI) (p = 0.100) on SPOF. To our knowledge, this is the first study reporting human small bowel SPOF. Little research has been published about procedure-specific data on human small bowel. Filling this gap in research will inform the design of more accurate human bowel synthetic models and provide an accurate baseline for training and clinical applications.
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Affiliation(s)
- Alex T Gong
- Department of Surgery, University of Washington, 1959 NE Pacific Ave, Magnuson Health Sciences T293, Seattle, WA 98195-0000
| | - Shi-Wen Olivia Yau
- Department of Surgery, University of Washington, 1959 NE Pacific Ave Magnuson Health Sciences T293, Seattle, WA 98195-0000; Department of Human Centered Design and Engineering, University of Washington, 3960 Benton Ln NE #428, Seattle, WA 98195-0000
| | - Hans B Erickson
- Department of Surgery, University of Washington, 1959 NE Pacific Ave, Magnuson Health Sciences T293, Seattle, WA 98195-0000; Department of Mechanical Engineering, University of Washington, 371 Loew Hall, Seattle, WA 98195-0000
| | - Rudolph J Toepfer
- Department of Surgery, University of Washington, 1959 NE Pacific Ave, Magnuson Health Sciences T293, Seattle, WA 98195-0000; Department of Materials Science and Engineering, University of Washington, 302 Roberts Hall, Seattle, WA 98195-2120
| | - Jessica Zhang
- Department of Surgery, University of Washington, 1959 NE Pacific Ave, Magnuson Health Sciences T293, Seattle, WA 98195-0000; Department of Biochemistry, University of Washington, 1959 NE Pacific Ave, Magnuson Health Sciences J405, Seattle, WA 98195-0000
| | - Aleah M Deschmidt
- Benaroya Research Institute at Virginia Mason, 1201 Ninth Ave, Seattle, WA 98101
| | - Conner J Parsey
- Medical Simulation Research Branch Simulation and Training Technology Center, U.S. Army DEVCOM Soldier Center, 12423 Research Parkway, Orlando, FL 32826
| | - Jack E Norfleet
- Medical Simulation Research Branch Simulation and Training Technology Center, U.S. Army DEVCOM Soldier Center, 12423 Research Parkway, Orlando, FL 32826
| | - Robert M Sweet
- Department of Surgery, University of Washington, 1959 NE Pacific Ave, Magnuson Health Sciences T293, Seattle, WA 98195-0000; Department of Urology, University of Washington, 1959 NE Pacific Ave, Magnuson Health Sciences T293, Seattle, WA 98195-0000; Department of Bioengineering, University of Washington, 3720 15th Ave NE, Seattle, WA 98195-0000
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4
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Friis SJ, Hansen TS, Poulsen M, Gregersen H, Brüel A, Vinge Nygaard J. Biomechanical properties of the stomach: A comprehensive comparative analysis of human and porcine gastric tissue. J Mech Behav Biomed Mater 2023; 138:105614. [PMID: 36527978 DOI: 10.1016/j.jmbbm.2022.105614] [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: 09/05/2022] [Revised: 11/23/2022] [Accepted: 12/06/2022] [Indexed: 12/14/2022]
Abstract
BACKGROUND Stomach-related disorders impose medical challenges and are associated with significant social and economic costs. The field of biomechanics is promising for understanding tissue behavior and for development of medical treatments and surgical interventions. In gastroenterology, animal models are often used when studies on humans are not possible. Often large animal models with similar anatomical characteristics (size and shape) are preferred. However, it is uncertain if stomachs from humans and large animals have similar mechanical properties. The aim of the present study is to characterize and compare hyper- and viscoelastic properties of porcine and human gastric tissue using tension and radial compression tests. METHODS Hyperelastic and viscoelastic properties were quantified from quasi-static ramp tests and stress relaxation tests. Tension in two directions and radial compression experiments were done on intact stomach wall samples as well as on separated mucosa and muscularis layer samples from porcine and human fundus, corpus and antrum. RESULTS AND CONCLUSIONS Similar hyper- and viscoelastic constitutive models can be used to describe porcine and human gastric tissue. In total, 19 constitutive parameters were compared and results showed significant variations between species. For example, for intact circumferential samples from antrum, the stiffness (a) and relaxation (τ1) were greater for human samples than for porcine samples (p < 0.0001). The constitutive parameters were condition-, region- and layer-dependent and no distinct pattern hereof between species was found. This indicates that different parameters must be used to describe the specific situation. The present work provides insight into porcine and human gastric radial compressive and tensile hyper- and viscoelastic properties, strengthening the inter-species relation of the biomechanical properties. Constitutive relations were established that may aid development and translation of diagnostic or therapeutic devices with computational models.
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Affiliation(s)
- Sif Julie Friis
- Department of Biological and Chemical Engineering, Aarhus University, Aarhus, Denmark; Alternative Delivery Technologies, Device & Delivery Solutions, Novo Nordisk A/S, Hilleroed, Denmark
| | | | - Mette Poulsen
- Alternative Delivery Technologies, Device & Delivery Solutions, Novo Nordisk A/S, Hilleroed, Denmark
| | - Hans Gregersen
- California Medical Innovations Institute, San Diego, CA, USA
| | - Annemarie Brüel
- Department of Biomedicine, Aarhus University, Aarhus, Denmark
| | - Jens Vinge Nygaard
- Department of Biological and Chemical Engineering, Aarhus University, Aarhus, Denmark.
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5
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Wu Y, Dong X, Kim JK, Wang C, Sitti M. Wireless soft millirobots for climbing three-dimensional surfaces in confined spaces. SCIENCE ADVANCES 2022; 8:eabn3431. [PMID: 35622917 PMCID: PMC9140972 DOI: 10.1126/sciadv.abn3431] [Citation(s) in RCA: 31] [Impact Index Per Article: 15.5] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/19/2021] [Accepted: 04/11/2022] [Indexed: 06/01/2023]
Abstract
Wireless soft-bodied robots at the millimeter scale allow traversing very confined unstructured terrains with minimal invasion and safely interacting with the surrounding environment. However, existing untethered soft millirobots still lack the ability of climbing, reversible controlled surface adhesion, and long-term retention on unstructured three-dimensional (3D) surfaces, limiting their use in biomedical and environmental applications. Here, we report a fundamental peeling-and-loading mechanism to allow untethered soft-bodied robots to climb 3D surfaces by using both the soft-body deformation and whole-body motion of the robot under external magnetic fields. This generic mechanism is implemented with different adhesive robot footpad designs, allowing vertical and inverted surface climbing on diverse 3D surfaces with complex geometries and different surface properties. With the unique robot footpad designs that integrate microstructured adhesives and tough bioadhesives, the soft climbing robot could achieve controllable adhesion and friction to climb 3D soft and wet surfaces including porcine tissues, which paves the way for future environmental inspection and minimally invasive medicine applications.
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Affiliation(s)
- Yingdan Wu
- Physical Intelligence Department, Max Planck Institute for Intelligent Systems, Stuttgart, 70569, Germany
| | - Xiaoguang Dong
- Physical Intelligence Department, Max Planck Institute for Intelligent Systems, Stuttgart, 70569, Germany
- Department of Mechanical Engineering, Vanderbilt University, Nashville, TN 37235, USA
| | - Jae-kang Kim
- Physical Intelligence Department, Max Planck Institute for Intelligent Systems, Stuttgart, 70569, Germany
| | - Chunxiang Wang
- Physical Intelligence Department, Max Planck Institute for Intelligent Systems, Stuttgart, 70569, Germany
| | - Metin Sitti
- Physical Intelligence Department, Max Planck Institute for Intelligent Systems, Stuttgart, 70569, Germany
- Institute for Biomedical Engineering, ETH Zürich, Zürich 8092, Switzerland
- School of Medicine and College of Engineering, Koç University, Istanbul 34450, Turkey
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6
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Preliminary study of reliability of transcutaneous sensors in measuring intraabdominal pressure. Sci Rep 2022; 12:8268. [PMID: 35585106 PMCID: PMC9117299 DOI: 10.1038/s41598-022-12388-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2021] [Accepted: 04/25/2022] [Indexed: 11/11/2022] Open
Abstract
Early recognition of elevated intraabdominal pressure (IAP) in critically ill patients is essential, since it can result in abdominal compartment syndrome, which is a life-threatening condition. The measurement of intravesical pressure is currently considered the gold standard for IAP assessment. Alternative methods have been proposed, where IAP assessment is based on measuring abdominal wall tension, which reflects the pressure in the abdominal cavity. The aim of this study was to evaluate the feasibility of using patch-like transcutaneous sensors to estimate changes in IAP, which could facilitate the monitoring of IAP in clinical practice. This study was performed with 30 patients during early postoperative care. All patients still had an indwelling urinary catheter postoperatively. Four wearable sensors were attached to the outer surface of the abdominal region to detect the changes in abdominal wall tension. Additionally, surface EMG was used to monitor the activity of the abdominal muscles. The thickness of the subcutaneous tissue was measured with ultrasound. Patients performed 4 cycles of the Valsalva manoeuvre, with a resting period in between (the minimal resting period was 30 s, with a prolongation as necessary to ensure that the fluid level in the measuring system had equilibrated). The IAP was estimated with intravesical pressure measurements during all resting periods and all Valsalva manoeuvres, while the sensors continuously measured changes in abdominal wall tension. The association between the subcutaneous thickness and tension changes on the surface and the intraabdominal pressure was statistically significant, but a large part of the variability was explained by individual patient factors. As a consequence, the predictions of IAP using transcutaneous sensors were not biased, but they were quite variable. The specificity of detecting intraabdominal pressure of 20 mmHg and above is 88%, with an NPV of 96%, while its sensitivity and PPV are currently far lower. There are inherent limitations of the chosen preliminary study design that directly caused the low sensitivity of our method as well as the poor agreement with the gold standard method; in spite of that, we have shown that these sensors have the potential to be used to monitor intraabdominal pressure. We are planning a study that would more closely resemble the intended clinical use and expect it to show more consistent results with a far smaller error.
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7
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Li M, Pan G, Zhang H, Guo B. Hydrogel adhesives for generalized wound treatment: Design and applications. JOURNAL OF POLYMER SCIENCE 2022. [DOI: 10.1002/pol.20210916] [Citation(s) in RCA: 10] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Affiliation(s)
- Meng Li
- State Key Laboratory for Mechanical Behavior of Materials, and Frontier Institute of Science and Technology Xi'an Jiaotong University Xi'an China
| | - Guoying Pan
- State Key Laboratory for Mechanical Behavior of Materials, and Frontier Institute of Science and Technology Xi'an Jiaotong University Xi'an China
| | - Hualei Zhang
- State Key Laboratory for Mechanical Behavior of Materials, and Frontier Institute of Science and Technology Xi'an Jiaotong University Xi'an China
| | - Baolin Guo
- State Key Laboratory for Mechanical Behavior of Materials, and Frontier Institute of Science and Technology Xi'an Jiaotong University Xi'an China
- Key Laboratory of Shaanxi Province for Craniofacial Precision Medicine Research College of Stomatology, Xi'an Jiaotong University Xi'an China
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8
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Singh G, Chanda A. Mechanical properties of whole-body soft human tissues: a review. Biomed Mater 2021; 16. [PMID: 34587593 DOI: 10.1088/1748-605x/ac2b7a] [Citation(s) in RCA: 78] [Impact Index Per Article: 26.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/08/2021] [Accepted: 09/29/2021] [Indexed: 11/11/2022]
Abstract
The mechanical properties of soft tissues play a key role in studying human injuries and their mitigation strategies. While such properties are indispensable for computational modelling of biological systems, they serve as important references in loading and failure experiments, and also for the development of tissue simulants. To date, experimental studies have measured the mechanical properties of peripheral tissues (e.g. skin)in-vivoand limited internal tissuesex-vivoin cadavers (e.g. brain and the heart). The lack of knowledge on a majority of human tissues inhibit their study for applications ranging from surgical planning, ballistic testing, implantable medical device development, and the assessment of traumatic injuries. The purpose of this work is to overcome such challenges through an extensive review of the literature reporting the mechanical properties of whole-body soft tissues from head to toe. Specifically, the available linear mechanical properties of all human tissues were compiled. Non-linear biomechanical models were also introduced, and the soft human tissues characterized using such models were summarized. The literature gaps identified from this work will help future biomechanical studies on soft human tissue characterization and the development of accurate medical models for the study and mitigation of injuries.
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Affiliation(s)
- Gurpreet Singh
- Centre for Biomedical Engineering, Indian Institute of Technology (IIT), Delhi, India
| | - Arnab Chanda
- Centre for Biomedical Engineering, Indian Institute of Technology (IIT), Delhi, India.,Department of Biomedical Engineering, All India Institute of Medical Sciences (AIIMS), Delhi, India
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9
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Hsu YT, Ho MH, Lee SP, Kao CY. Preparation of Biomimetic 3D Gastric Model with Photo-Curing Resin and Evaluation the Growth of Helicobacter pylori. Polymers (Basel) 2021; 13:polym13203593. [PMID: 34685352 PMCID: PMC8538753 DOI: 10.3390/polym13203593] [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: 09/18/2021] [Revised: 10/12/2021] [Accepted: 10/16/2021] [Indexed: 11/20/2022] Open
Abstract
Three-dimensional (3D) printing technology is now widely used in biomedical developments. Especially, photo-curing systems provide high resolution and precision. The current goal of biomedical 3D printing technology is the printing of human organs, but the current commercial photo-curable materials generally have high mechanical strength that cannot meet the mechanical properties of the object to be printed. In this research, a gastric model was printed using a photo-curing 3D printing technique. To mimic the wrinkle pattern of human gastric tissue, cis-1,4 polyisoprene with different reactive diluents was mixed and identified a formulation that produced a print with human gastric softness. This research discussed the effect of the Young’s modulus of the material and elucidated the relationship between the degree of conversion rate and viscosity. After modifying the cis-1,4 polyisoprene surface from hydrophobic to hydrophilic, we then evaluated its adhesion efficiency for gastric mucin and the gastrointestinal-inhabiting bacterium Helicobacter pylori.
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Affiliation(s)
- Yu-Tung Hsu
- Department of Chemical Engineering, National Taiwan University of Science and Technology, Taipei 10607, Taiwan; (Y.-T.H.); (M.-H.H.)
| | - Ming-Hu Ho
- Department of Chemical Engineering, National Taiwan University of Science and Technology, Taipei 10607, Taiwan; (Y.-T.H.); (M.-H.H.)
- R&D Center for Membrane Technology, National Taiwan University of Science and Technology, Taipei 10607, Taiwan
| | - Shiao-Pieng Lee
- Department of Dentistry, Division of Oral and Maxillofacial Surgery, Tri-Service General Hospital, Taipei 11490, Taiwan;
- Department of Biomedical Engineering, National Defense Medical Center, Taipei 11490, Taiwan
| | - Chen-Yu Kao
- Graduate Institute of Biomedical Engineering, National Taiwan University of Science and Technology, Taipei 10607, Taiwan
- Biomedical Engineering Research Center, National Defense Medical Center, Taipei 11490, Taiwan
- Correspondence: ; Tel.: +886-2-2730-3676
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10
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Cabibihan JJ, Alhaddad AY, Gulrez T, Yoon WJ. Influence of Visual and Haptic Feedback on the Detection of Threshold Forces in a Surgical Grasping Task. IEEE Robot Autom Lett 2021. [DOI: 10.1109/lra.2021.3068934] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
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11
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Wang W, Zeng Z, Xiang L, Liu C, Diaz-Dussan D, Du Z, Asha AB, Yang W, Peng YY, Pan M, Narain R, Liu J, Zeng H. Injectable Self-Healing Hydrogel via Biological Environment-Adaptive Supramolecular Assembly for Gastric Perforation Healing. ACS NANO 2021; 15:9913-9923. [PMID: 34037373 DOI: 10.1021/acsnano.1c01199] [Citation(s) in RCA: 34] [Impact Index Per Article: 11.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/12/2023]
Abstract
Developing effective internal wound dressing materials is important for postoperative tissue regeneration while remains a challenge due to the poor biological environment-adaptability of conventional materials. Here, we report an example of injectable self-healing hydrogel based on gastric environment-adaptive supramolecular assembly, and have explored its application for gastric perforation healing. By leveraging the gastric environment-modulated supramolecular interactions, the self-assembled hydrogel network is orchestrated with sensitive thermo-responsibility, injectability, printability and rapid self-healing capability. The hydrogel dressing can effectively inhibit the attachment of microorganisms and demonstrates outstanding antibiofouling property. In vivo rat model further demonstrates the as-prepared hydrogel dressing simplifies the surgical procedures, reduces postoperative complications as well as enhances the healing process of gastric perforation compared with the conventional treatment. This work provides useful insights into the development of biological environment-adaptive functional materials for various biomedical applications.
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Affiliation(s)
- Wenda Wang
- Department of Chemical and Materials Engineering, University of Alberta, T6G 1H9 Edmonton, Canada
| | - Zicheng Zeng
- Cancer Center, The Fifth Affiliated Hospital, Guangzhou Medical University, 510700 Guangzhou, People's Republic of China
| | - Li Xiang
- Department of Chemical and Materials Engineering, University of Alberta, T6G 1H9 Edmonton, Canada
| | - Cong Liu
- Cancer Center, The Fifth Affiliated Hospital, Guangzhou Medical University, 510700 Guangzhou, People's Republic of China
| | - Diana Diaz-Dussan
- Department of Chemical and Materials Engineering, University of Alberta, T6G 1H9 Edmonton, Canada
| | - Zunguo Du
- Department of Pathology, Huashan Hospital, Fudan University, 200040 Shanghai, People's Republic of China
| | - Anika B Asha
- Department of Chemical and Materials Engineering, University of Alberta, T6G 1H9 Edmonton, Canada
| | - Wenshuai Yang
- Department of Chemical and Materials Engineering, University of Alberta, T6G 1H9 Edmonton, Canada
| | - Yi-Yang Peng
- Department of Chemical and Materials Engineering, University of Alberta, T6G 1H9 Edmonton, Canada
| | - Mingfei Pan
- Department of Chemical and Materials Engineering, University of Alberta, T6G 1H9 Edmonton, Canada
| | - Ravin Narain
- Department of Chemical and Materials Engineering, University of Alberta, T6G 1H9 Edmonton, Canada
| | - Jifang Liu
- Cancer Center, The Fifth Affiliated Hospital, Guangzhou Medical University, 510700 Guangzhou, People's Republic of China
| | - Hongbo Zeng
- Department of Chemical and Materials Engineering, University of Alberta, T6G 1H9 Edmonton, Canada
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12
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Chiroiu V, Nedelcu N, Pisla D, Munteanu L, Rugină C. On the flexible needle insertion into the human liver. Sci Rep 2021; 11:10251. [PMID: 33986330 PMCID: PMC8119694 DOI: 10.1038/s41598-021-89479-8] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/19/2020] [Accepted: 02/15/2021] [Indexed: 01/03/2023] Open
Abstract
In the present research, the navigation of a flexible needle into the human liver in the context of the robotic-assisted intraoperative treatment of the liver tumors, is reported. Cosserat (micropolar) elasticity is applied to describe the interaction between the needle and the human liver. The theory incorporates the local rotation of points and the couple stress (a torque per unit area) as well as the force stress (force per unit area) representing the chiral features of the human liver. To predict the deformation of the needle and the liver, the elastic properties of the human liver have been evaluated. Outcomes reveal that considering smaller deformations of the needle and the liver results in better needle navigation mechanism. The needle geometry can enhance the penetration.
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Affiliation(s)
- Veturia Chiroiu
- Institute of the Solid Mechanics, Romanian Academy, Bucharest, Romania.
| | - Nicoleta Nedelcu
- Institute of the Solid Mechanics, Romanian Academy, Bucharest, Romania
| | - Doina Pisla
- Technical University of Cluj-Napoca, Cluj-Napoca, Romania
| | - Ligia Munteanu
- Institute of the Solid Mechanics, Romanian Academy, Bucharest, Romania
| | - Cristian Rugină
- Institute of the Solid Mechanics, Romanian Academy, Bucharest, Romania
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13
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Tsibulskaya E, Lipovka A, Chupakhin A, Dubovoy A, Parshin D, Maslov N. The Relationship between the Strength Characteristics of Cerebral Aneurysm Walls with Their Status and Laser-Induced Fluorescence Data. Biomedicines 2021; 9:biomedicines9050537. [PMID: 34065958 PMCID: PMC8151487 DOI: 10.3390/biomedicines9050537] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2021] [Revised: 05/01/2021] [Accepted: 05/07/2021] [Indexed: 11/16/2022] Open
Abstract
Background: Cerebral aneurysms (CA) are a widespread vascular disease affecting 50 per 1000 population. The study of the influence of histological, morphological and hemodynamic factors on the status of the aneurysm has been the subject of many works. However, an accurate and generally accepted relationship has not yet been identified. Methods: In our work, the results of mechanical and spectroscopic measurements are considered. Total investigated 14 patients and 36 their samples of CA tissue. Results: The excitation–emission matrix of each specimen was evaluated, after which the strength characteristics of the samples were investigated. Conclusions: It has been shown that there is a statistically significant difference in the size of the peaks of two components, which characterizes the status of the aneurysms. In addition, a linear regression model has been built that describes the correlation of the magnitude of the ultimate strain and stress with the magnitude of the peaks of one of the components. The results of this study will serve as a basis for the non-invasive determination of the strength characteristics of the cerebral tissue aneurysms and determination of their status.
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Affiliation(s)
- Elena Tsibulskaya
- Khristianovich Institute of Theoretical and Applied Mechanics SB RAS, 630090 Novosibrsk, Russia; (E.T.); (N.M.)
| | - Anna Lipovka
- Lavrentyev Institute of Hydrodynamics SB RAS, 630090 Novosibirsk, Russia; (A.C.); (A.D.); (D.P.)
- Correspondence:
| | - Alexandr Chupakhin
- Lavrentyev Institute of Hydrodynamics SB RAS, 630090 Novosibirsk, Russia; (A.C.); (A.D.); (D.P.)
| | - Andrey Dubovoy
- Lavrentyev Institute of Hydrodynamics SB RAS, 630090 Novosibirsk, Russia; (A.C.); (A.D.); (D.P.)
- Federal Neurosurgical Center, 630048 Novosibirsk, Russia
| | - Daniil Parshin
- Lavrentyev Institute of Hydrodynamics SB RAS, 630090 Novosibirsk, Russia; (A.C.); (A.D.); (D.P.)
| | - Nikolay Maslov
- Khristianovich Institute of Theoretical and Applied Mechanics SB RAS, 630090 Novosibrsk, Russia; (E.T.); (N.M.)
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Debelle A, de Rooster H, Bianchini E, Lonys L, Huberland F, Vanhoestenberghe A, Lambert P, Acuña V, Smets H, Giannotta F, Delchambre A, Sandersen C, Bolen G, Egyptien S, Deleuze S, Devière J, Nonclercq A. Optimization and assessment of a novel gastric electrode anchoring system designed to be implanted by minimally invasive surgery. Med Eng Phys 2021; 92:93-101. [PMID: 34167717 DOI: 10.1016/j.medengphy.2021.05.004] [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: 12/07/2020] [Revised: 04/27/2021] [Accepted: 05/05/2021] [Indexed: 11/16/2022]
Abstract
A novel electrode anchoring design and its implantation procedure, aiming for a minimally invasive solution for gastric electrical stimulation, are presented. The system comprises an anchor made of a flexible body embedding two needle-shaped electrodes. The electrodes can easily switch from a parallel position - to pierce the stomach - to a diverging position - enabling them to remain firmly anchored into the muscular layer of the stomach. Key device parameters governing anchoring stability were assessed on a traction test bench, and optimal values were derived. The device was then implanted in six dogs by open surgery to assess its anchoring durability in vivo. Computed tomography images showed that the electrodes remained well placed within the dogs' gastric wall over the entire assessment period (more than one year). Finally, a prototype of a surgical tool for the minimally invasive device placement was manufactured, and the anchoring procedure was tested on a dog cadaver, providing the proof of concept of the minimally invasive implantation procedure. The use of our electrode anchoring system in long-term gastric electrical stimulation is promising in terms of implantation stability (the anchor withstands a force up to 0.81 N), durability (the anchor remains onto the stomach over one year) and minimal invasiveness of the procedure (the diameter of the percutaneous access is smaller than 12 mm). Moreover, the proposed design could have clinical applications in other hollow organs, such as the urinary bladder.
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Affiliation(s)
- Adrien Debelle
- Bio, Electro and Mechanical Systems Department (BEAMS), Ecole Polytechnique de Bruxelles, Université Libre de Bruxelles, Brussels, Belgium.
| | - Hilde de Rooster
- Small Animal Department, Faculty of Veterinary Medicine, Ghent University, Ghent, Belgium
| | - Erika Bianchini
- Small Animal Department, Faculty of Veterinary Medicine, Ghent University, Ghent, Belgium
| | - Laurent Lonys
- Bio, Electro and Mechanical Systems Department (BEAMS), Ecole Polytechnique de Bruxelles, Université Libre de Bruxelles, Brussels, Belgium
| | - François Huberland
- Bio, Electro and Mechanical Systems Department (BEAMS), Ecole Polytechnique de Bruxelles, Université Libre de Bruxelles, Brussels, Belgium
| | - Anne Vanhoestenberghe
- Aspire Centre for Rehabilitation Engineering and Assistive Technology, Department of Materials and Tissue, University College London, Stanmore, United Kingdom
| | - Pierre Lambert
- Transfers, Interfaces and Processes Department (TIPS), Ecole Polytechnique de Bruxelles, Université Libre de Bruxelles, Brussels, Belgium
| | - Vicente Acuña
- Bio, Electro and Mechanical Systems Department (BEAMS), Ecole Polytechnique de Bruxelles, Université Libre de Bruxelles, Brussels, Belgium
| | - Hugo Smets
- Bio, Electro and Mechanical Systems Department (BEAMS), Ecole Polytechnique de Bruxelles, Université Libre de Bruxelles, Brussels, Belgium
| | - Fabrizio Giannotta
- Bio, Electro and Mechanical Systems Department (BEAMS), Ecole Polytechnique de Bruxelles, Université Libre de Bruxelles, Brussels, Belgium
| | - Alain Delchambre
- Bio, Electro and Mechanical Systems Department (BEAMS), Ecole Polytechnique de Bruxelles, Université Libre de Bruxelles, Brussels, Belgium
| | - Charlotte Sandersen
- Fundamental and Applied Research for Animal & Health (FARAH), Department of Clinical Sciences, Faculty of Veterinary Medicine, University of Liege, Liege, Belgium
| | - Geraldine Bolen
- Fundamental and Applied Research for Animal & Health (FARAH), Department of Clinical Sciences, Faculty of Veterinary Medicine, University of Liege, Liege, Belgium
| | - Sophie Egyptien
- Fundamental and Applied Research for Animal & Health (FARAH), Department of Clinical Sciences, Faculty of Veterinary Medicine, University of Liege, Liege, Belgium
| | - Stefan Deleuze
- Fundamental and Applied Research for Animal & Health (FARAH), Department of Clinical Sciences, Faculty of Veterinary Medicine, University of Liege, Liege, Belgium
| | - Jacques Devière
- Department of Gastroenterology, Hepatopancreatology, and Digestive Oncology, Erasmus University Hospital, Université Libre de Bruxelles, Brussels, Belgium
| | - Antoine Nonclercq
- Bio, Electro and Mechanical Systems Department (BEAMS), Ecole Polytechnique de Bruxelles, Université Libre de Bruxelles, Brussels, Belgium
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Application of micro-computer tomography and inverse finite element analysis for characterizing the visco-hyperelastic response of bulk liver tissue using indentation. SN APPLIED SCIENCES 2021. [DOI: 10.1007/s42452-021-04577-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022] Open
Abstract
Abstract
In-vitro mechanical indentation experimentation is performed on bulk liver tissue of lamb to characterize its nonlinear material behaviour. The material response is characterized by a visco-hyperelastic material model by the use of 2-dimensional inverse finite element (FE) analysis. The time-dependent behaviour is characterized by the viscoelastic model represented by a 4-parameter Prony series, whereas the large deformations are modelled using the hyperelastic Neo-Hookean model. The shear response described by the initial and final shear moduli and the corresponding Prony series parameters are optimized using ANSYS with the Root Mean Square (RMS) error being the objective function. Optimized material properties are validated using experimental results obtained under different loading histories. To study the efficacy of a 2D model, a three dimensional (3D) model of the specimen is developed using Micro-CT of the specimen. The initial elastic modulus of the lamb liver obtained was found to 13.5 kPa for 5% indentation depth at a loading rate of 1 mm/sec for 1-cycle. These properties are able to predict the response at 8.33% depth and a loading rate of 5 mm/sec at multiple cycles with reasonable accuracy.
Article highlights
The visco-hyperelastic model accurately models the large displacement as well as the time-dependent behaviour of the bulk liver tissue.
Mapped meshing of the 3D FE model saves computational time and captures localized displacement in an accurate manner.
The 2D axisymmetric model while predicting the force response of the bulk tissue, cannot predict the localized deformations.
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Comparison of Thiel preserved, fresh human, and animal liver tissue in terms of mechanical properties. Ann Anat 2021; 236:151717. [PMID: 33689839 DOI: 10.1016/j.aanat.2021.151717] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/07/2020] [Revised: 01/26/2021] [Accepted: 02/09/2021] [Indexed: 12/17/2022]
Abstract
BACKGROUND In medical training and research fresh human tissue is often replaced by preserved human or fresh animal tissue, due to availability and ethical reasons. Newer preservation approaches, such as the Thiel method, promise more realistic mechanical properties than conventional formaldehyde fixation. Concerning animal substitute material, porcine and bovine tissue is often chosen, as it is easily obtainable and certain similarity to human tissue is assumed. However, it has not been thoroughly investigated how Thiel preservation changes non-linear and viscoelastic behaviour of soft organ tissues. Furthermore, differences in these properties between animal tissue and human tissue have not been previously corroborated. METHODS We conducted ramp and relaxation tensile tests on fresh human and Thiel preserved hepatic tissue, extracting strain-specific elastic moduli, and viscoelastic properties. The results for fresh human liver were then compared to corresponding results for Thiel preserved liver, as well as previously published results for porcine and bovine liver. RESULTS Our results showed that Thiel preservation seems to be associated with increased stiffness as well as decreased viscoelastic damping behaviour. Porcine liver was stiffer than human liver with similar viscoelastic properties. Bovine liver exhibited similar stiffness as human liver, however lower viscoelastic damping. CONCLUSIONS The differences between human and animal liver tissue, concerning their mechanical properties, can be explained by their characteristic histology. Changes in mechanical properties due to Thiel preservation might stem from altered protein cross-linking and dehydration. The results illustrate that appropriate materials for medical training systems must be selected based on which mechanical properties are relevant for the respective application.
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Estermann SJ, Pahr DH, Reisinger A. Hyperelastic and viscoelastic characterization of hepatic tissue under uniaxial tension in time and frequency domain. J Mech Behav Biomed Mater 2020; 112:104038. [PMID: 32889334 DOI: 10.1016/j.jmbbm.2020.104038] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/29/2020] [Revised: 08/03/2020] [Accepted: 08/10/2020] [Indexed: 01/28/2023]
Abstract
In order to create accurate anatomical models for medical training and research, mechanical properties of biological tissues need to be studied. However, non-linear and viscoelastic behaviour of most soft biological tissues complicates the evaluation of their mechanical properties. In the current study, a method for measuring hyperelasticity and viscoelasticity of bovine and porcine hepatic parenchyma in tension is presented. First, non-linear stress-stretch curves resulting from ramp loading and unloading, were interpreted based on a hyperelastic framework, using a Veronda-Westmann strain energy function. Strain-specific elastic moduli, such as initial stiffness EI, were thereupon defined in certain parts of the stress-stretch curves. Furthermore, dissipated and stored energy density were calculated. Next, the viscoelastic nature of liver tissue was examined with two different methods: stress relaxation and dynamic cyclic testing. Both tests yielded dissipated and stored energy density, as well as loss tangent (tanδ), storage modulus (E'), and loss modulus (E''). In tension, stress relaxation was experimentally more convenient than dynamic cyclic testing. Thus we considered whether relaxation could be used for approximating the results of the cyclic tests. Regarding the resulting elastic moduli, initial stiffness was similar for porcine and bovine liver (EI∼30kPa), while porcine liver was stiffer for higher strains. Comparing stress relaxation with dynamic cyclic testing, tanδ of porcine and bovine liver was the same for both methods (tanδ=0.05-0.25 at 1 Hz). Storage and loss moduli matched well for bovine, but not as well for porcine tissue. In conclusion, the utilized Veronda-Westmann model was appropriate for representing the hyperelasticity of liver tissue seen in ramp tests. Concerning viscoelasticity, both chosen testing methods - stress relaxation and dynamic cyclic testing - yielded comparable results for E', E'', and tanδ, as long as elasticity non-linearities were heeded. The here presented method provides novel insight into the tensile viscoelastic properties of hepatic tissue, and provides guidelines for convenient evaluation of soft tissue mechanical properties.
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Affiliation(s)
- Sarah-Jane Estermann
- Department Anatomy and Biomechanics, Karl Landsteiner University of Health Sciences, Dr.-Karl-Dorrek-Straße 30, 3500 Krems an der Donau, Austria; Austrian Center for Medical Innovation and Technology, Viktor Kaplan-Straße 2/1, 2700 Wiener Neustadt, Austria; Institute for Lightweight Design and Structural Biomechanics, TU-Wien, Getreidemarkt 9, 1060 Wien, Austria
| | - Dieter H Pahr
- Department Anatomy and Biomechanics, Karl Landsteiner University of Health Sciences, Dr.-Karl-Dorrek-Straße 30, 3500 Krems an der Donau, Austria; Institute for Lightweight Design and Structural Biomechanics, TU-Wien, Getreidemarkt 9, 1060 Wien, Austria
| | - Andreas Reisinger
- Department Anatomy and Biomechanics, Karl Landsteiner University of Health Sciences, Dr.-Karl-Dorrek-Straße 30, 3500 Krems an der Donau, Austria.
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Han H, Lee DY. Deformable objects modeling with iterative updates of local positions. COMPUTER METHODS AND PROGRAMS IN BIOMEDICINE 2020; 190:105346. [PMID: 32014719 DOI: 10.1016/j.cmpb.2020.105346] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/25/2019] [Revised: 11/28/2019] [Accepted: 01/16/2020] [Indexed: 06/10/2023]
Abstract
BACKGROUND AND OBJECTIVE Deformation of elastic material such as soft tissues of human body in the virtual environment is computed based on actual material properties. But this often leads to computational overhead hindering real-time simulation. This paper proposes a new modeling method of deformable objects for real-time simulation, using iterative updates of local positions, and control of the desired behavior by material properties. METHOD The Saint Venant-Kirchhoff model is used to form the governing equation to express and control the nonlinear behavior and properties of the material. This governing equation is combined with a local iterative solver using position-based dynamics framework. The proposed method updates the local positions iteratively by finding the solution to minimize the energy of related elements surrounding the target nodes. A grouping method is devised to determine the optimal order of computation. RESULT Various dynamic behaviors can be simulated using the proposed method corresponding to different Young's modulus. Maximum deformations simulated by the proposed method are compared with those results from commercial ANSYS. Relative errors of the real-time simulation results are less than 15% when Young's modulus ranges from 4 kPa to 10 kPa. Real-time performance is evaluated using a liver model composed of 596 tetrahedral elements. CONCLUSION Simulation results show that the proposed method can simulate, in real-time, the stiffness of the model faithfully according to their material properties.
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Affiliation(s)
- Hyehyun Han
- Department of Mechanical Engineering, Korea Advanced Institute of Science and Technology, 291 Daehak-ro, Yuseong-gu, Daejeon 34141, Republic of Korea
| | - Doo Yong Lee
- Department of Mechanical Engineering, Korea Advanced Institute of Science and Technology, 291 Daehak-ro, Yuseong-gu, Daejeon 34141, Republic of Korea.
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19
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Quantifying tactile properties of liver tissue, silicone elastomers, and a 3D printed polymer for manufacturing realistic organ models. J Mech Behav Biomed Mater 2020; 104:103630. [DOI: 10.1016/j.jmbbm.2020.103630] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/02/2019] [Revised: 01/07/2020] [Accepted: 01/08/2020] [Indexed: 01/17/2023]
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Ponukumati AS, Wu X, Kahng PW, Skinner J, Paydarfar JA, Halter RJ. A System for Characterizing Intraoperative Force Distribution During Operative Laryngoscopy. IEEE Trans Biomed Eng 2020; 67:2616-2627. [PMID: 31976874 DOI: 10.1109/tbme.2020.2966954] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
OBJECTIVE This study aimed to create and validate an integrated data acquisition system for gauging the force distribution between a laryngoscope and soft-tissue during trans-oral surgery. METHODS Sixteen piezoresistive force sensors were interfaced to a laryngoscope and custom maxillary tooth guard. A protocol for calibrating the laryngoscope and maxilla sensors was developed using a motor-controlled linear stage and force measurements were validated against a digital scale. The system was initially tested during suspension laryngoscopy on three cadaver heads mounted on a cadaver head-holder. Intraoperative data was also collected from three patients undergoing head and neck tumor resection. RESULTS Mean calibration error of the scope sensors was less than 150 g (n = 3) and mean maxilla sensor error was less than 200 g (n = 3). Peak scope mag-forces of 8.09 ± 6.61 kg and peak maxilla forces of 7.62 ± 4.57 kg were experienced during the cadaver trials. The peak scope sensor mag-force recorded during the intraoperative cases was 24.7 ± 4.53 kg, and the peak maxilla force was 22.0 ± 4.60 kg. CONCLUSION The data acquisition system was successfully able to record intraoperative force distribution data. The usefulness of this technology in informing surgeons during trans-oral surgery should be further evaluated in patients with varying anatomic and procedural characteristics. SIGNIFICANCE Creation of a low-cost, integrated force-sensing system allows for the characterization of retraction forces at anatomic sites including the pharynx and larynx, brain, and abdomen. Real-time force detection provides surgeons with valuable intraoperative feedback and can be used to improve deformation models at various anatomic sites.
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Mancia L, Vlaisavljevich E, Yousefi N, Rodriguez M, Ziemlewicz TJ, Lee FT, Henann D, Franck C, Xu Z, Johnsen E. Modeling tissue-selective cavitation damage. Phys Med Biol 2019; 64:225001. [PMID: 31639778 PMCID: PMC6925591 DOI: 10.1088/1361-6560/ab5010] [Citation(s) in RCA: 28] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
The destructive growth and collapse of cavitation bubbles are used for therapeutic purposes in focused ultrasound procedures and can contribute to tissue damage in traumatic injuries. Histotripsy is a focused ultrasound procedure that relies on controlled cavitation to homogenize soft tissue. Experimental studies of histotripsy cavitation have shown that the extent of ablation in different tissues depends on tissue mechanical properties and waveform parameters. Variable tissue susceptibility to the large stresses, strains, and strain rates developed by cavitation bubbles has been suggested as a basis for localized liver tumor treatments that spare large vessels and bile ducts. However, field quantities developed within microns of cavitation bubbles are too localized and transient to measure in experiments. Previous numerical studies have attempted to circumvent this challenge but made limited use of realistic tissue property data. In this study, numerical simulations are used to calculate stress, strain, and strain rate fields produced by bubble oscillation under histotripsy forcing in a variety of tissues with literature-sourced viscoelastic and acoustic properties. Strain field calculations are then used to predict a theoretical damage radius using tissue ultimate strain data. Simulation results support the hypothesis that differential tissue responses could be used to design tissue-selective treatments. Results agree with studies correlating tissue ultimate fractional strain with resistance to histotripsy ablation and are also consistent with experiments demonstrating smaller lesion size under exposure to higher frequency waveforms. Methods presented in this study provide an approach for modeling tissue-selective cavitation damage in general.
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Affiliation(s)
- Lauren Mancia
- Department of Mechanical Engineering, University of Michigan, Ann Arbor, MI, United States of America. University of Michigan Medical School, Ann Arbor, MI, United States of America
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23
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Overtoom EM, Horeman T, Jansen FW, Dankelman J, Schreuder HWR. Haptic Feedback, Force Feedback, and Force-Sensing in Simulation Training for Laparoscopy: A Systematic Overview. JOURNAL OF SURGICAL EDUCATION 2019; 76:242-261. [PMID: 30082239 DOI: 10.1016/j.jsurg.2018.06.008] [Citation(s) in RCA: 39] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/26/2018] [Revised: 04/24/2018] [Accepted: 06/13/2018] [Indexed: 06/08/2023]
Abstract
OBJECTIVES To provide a systematic overview of the literature assessing the value of haptic and force feedback in current simulators teaching laparoscopic surgical skills. DATA SOURCES The databases of Pubmed, Cochrane, Embase, Web of Science, and Google Scholar were searched to retrieve relevant studies published until January 31st, 2017. The search included laparoscopic surgery, simulation, and haptic or force feedback and all relevant synonyms. METHODS Duplicates were removed, and titles and abstracts screened. The remaining articles were subsequently screened full text and included in this review if they followed the inclusion criteria. A total of 2 types of feedback have been analyzed and will be discussed separately: haptic- and force feedback. RESULTS A total of 4023 articles were found, of which 87 could be used in this review. A descriptive analysis of the data is provided. Results of the added value of haptic interface devices in virtual reality are variable. Haptic feedback is most important for more complex tasks. The interface devices do not require the highest level of fidelity. Haptic feedback leads to a shorter learning curve with a steadier upward trend. Concerning force feedback, force parameters are measured through force sensing systems in the instrument and/or the environment. These parameters, especially in combination with motion parameters, provide box trainers with an objective evaluation of laparoscopic skills. Feedback of force-use both real time and postpractice has been shown to improve training. CONCLUSIONS Haptic feedback is added to virtual reality simulators to increase the fidelity and thereby improve training effect. Variable results have been found from adding haptic feedback. It is most important for more complex tasks, but results in only minor improvements for novice surgeons. Force parameters and force feedback in box trainers have been shown to improve training results.
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Affiliation(s)
- Evelien M Overtoom
- Department of Gynaecology and Reproductive Medicine, University Medical Center Utrecht and Department of Gynaecologic Oncology, UMC Utrecht Cancer Centre, Utrecht, The Netherlands
| | - Tim Horeman
- Department of Biomechanical Engineering, Faculty of Mechanical Engineering, Delft University of Technology, Delft, The Netherlands
| | - Frank-Willem Jansen
- Department of Biomechanical Engineering, Faculty of Mechanical Engineering, Delft University of Technology, Delft, The Netherlands; Department of Gynaecology, Leiden University Medical Centre, Leiden, The Netherlands
| | - Jenny Dankelman
- Department of Biomechanical Engineering, Faculty of Mechanical Engineering, Delft University of Technology, Delft, The Netherlands
| | - Henk W R Schreuder
- Department of Gynaecology and Reproductive Medicine, University Medical Center Utrecht and Department of Gynaecologic Oncology, UMC Utrecht Cancer Centre, Utrecht, The Netherlands.
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Moores N, Conway H, Donato D, Gociman B, Pannucci CJ, Agarwal J. Is release of the posterior lamella enough? A cadaveric exploration of posterior component separation techniques. Am J Surg 2018; 218:533-536. [PMID: 30591182 DOI: 10.1016/j.amjsurg.2018.12.011] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/23/2018] [Revised: 12/05/2018] [Accepted: 12/10/2018] [Indexed: 01/04/2023]
Abstract
BACKGROUND As posterior component separation techniques continue to gain popularity there is uncertainty regarding the degree of fascial advancement afforded by the various techniques. Our study seeks to compare the degree anterior rectus sheath translation seen in full transversus abdominus release compared to simple release of the posterior lamella of the rectus sheath. METHODS Ten hemi-abdomens in five fresh cadavers were dissected. One hemi-abdomen underwent external oblique release. The contralateral hemi-abdomen underwent retrorectus dissection and initial release of the internal lamella of the internal oblique, followed by full transversus abdominus release. A 4 kg weight was suspended from the fascia and excursion was measured after 1) external oblique separation, 2) posterior lamella of the internal oblique separation, and 3) transversus abdominis separation. RESULTS Average unilateral hemifascial translation after release of the external oblique provided an average unilateral hemi-fascial translation of 3.38 cm (+/- 0.69). Release of the posterior lamella of the internal oblique provided 3.98 cm (+/- 0.94). After transversus release the average translation increased to 4.31 cm (+/- 0.89). CONCLUSIONS In this cadaveric study, the majority (92%) of fascial advancement afforded by posterior component separation was achieved by an intermediate step in the transversus abdominus release operation: division of the posterior lamella of the internal oblique.
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Affiliation(s)
- N Moores
- University of Utah, Division of Plastic Surgery, 30N 1900 E, #3B400, Salt Lake City, UT, 84132, USA.
| | - H Conway
- Huntsman Cancer Institute, 2000 Circle of Hope dr, Rm 5524.12, Salt Lake City, UT, 84123, USA.
| | - D Donato
- University of Utah, Division of Plastic Surgery, 30N 1900 E, #3B400, Salt Lake City, UT, 84132, USA.
| | - B Gociman
- University of Utah, Division of Plastic Surgery, 30N 1900 E, #3B400, Salt Lake City, UT, 84132, USA.
| | - C J Pannucci
- University of Utah, Division of Plastic Surgery, 30N 1900 E, #3B400, Salt Lake City, UT, 84132, USA.
| | - J Agarwal
- University of Utah, Division of Plastic Surgery, 30N 1900 E, #3B400, Salt Lake City, UT, 84132, USA.
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Abstract
Structural links from the nucleus to the cytoskeleton and to the extracellular environment play a role in direct mechanosensing by nuclear factors. Here, we highlight recent studies that illustrate nuclear mechanosensation processes ranging from DNA repair and nuclear protein phospho-modulation to chromatin reorganization, lipase activation by dilation, and reversible rupture with the release of nuclear factors. Recent progresses demonstrate that these mechanosensing processes lead to modulation of gene expression such as those involved in the regulation of cytoskeletal programs and introduce copy number variations. The nuclear lamina protein lamin A has a recurring role, and various biophysical analyses prove helpful in clarifying mechanisms. The various recent observations provide further motivation to understand the regulation of nuclear mechanosensing pathways in both physiological and pathological contexts.
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Vanderbeek C, Liu YF, Reichert Z, Thakker J, Collett T, Inman JC. Effect of Mandible and Maxilla Osteotomies on Velar, Oropharyngeal, and Hypopharyngeal Diameter. J Oral Maxillofac Surg 2018; 77:398-404. [PMID: 30077595 DOI: 10.1016/j.joms.2018.06.176] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2018] [Revised: 06/06/2018] [Accepted: 06/20/2018] [Indexed: 11/19/2022]
Abstract
PURPOSE There is a lack of anatomic comparisons between maxillomandibular advancement (MMA) and other bony surgical treatments of obstructive sleep apnea (OSA). Surgical procedures were simulated in cadavers to evaluate their ability to expand the posterior airway space (PAS). MATERIALS AND METHODS The following bony advancement surgeries were performed on each of 9 cadavers: genioglossal advancement (GGA); genioplasty with advancement of the genioglossus, geniohyoid, and anterior digastric muscles (GPA); bilateral sagittal split osteotomy; Le Fort I maxillary advancement; Le Fort I maxillary anterior impaction osteotomy (LFAI); MMA; MMA plus GPA; and MMA plus LFAI. Bony advancements were performed at increasing distances and change in PAS anteroposterior (AP) diameter was measured at the levels of the velum, oropharynx, and hypopharynx. RESULTS Change in PAS varied in a linear fashion with advancement surgical maneuvers. GPA led to a greater increase in AP distance at the levels of the oropharynx and hypopharynx compared with GGA. LFAI showed a greater increase in AP distance at the velum compared with MMA. All maxillary movements showed greater AP expansion in the PAS at the velum compared with mandibular advancements. CONCLUSIONS Static AP expansion of the PAS at the levels of the velum, oropharynx, and hypopharynx occurs in a roughly linear and predictable pattern with different bony surgical procedures used in OSA surgery. MMA alone and MMA plus GPA had the overall greatest effect at all airway levels. GPA had a greater effect on expansion of the oropharynx and hypopharynx compared with GGA.
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Affiliation(s)
- Christopher Vanderbeek
- Resident, Department of Oral and Maxillofacial Surgery, Loma Linda University, Loma Linda University Medical Center, Loma Linda, CA
| | - Yuan F Liu
- Resident, Department of Otolaryngology-Head and Neck Surgery, Loma Linda University Medical Center, Loma Linda, CA
| | - Zachary Reichert
- Student, Loma Linda University School of Medicine, Loma Linda, CA
| | - Jayini Thakker
- Program Director, Department of Oral and Maxillofacial Surgery, Loma Linda University, Loma Linda University Medical Center, Loma Linda, CA
| | - Tolbin Collett
- Resident, Department of Otolaryngology-Head and Neck Surgery, Loma Linda University Medical Center, Loma Linda, CA
| | - Jared C Inman
- Associate Professor, Department of Otolaryngology-Head and Neck Surgery, Loma Linda University Medical Center, Loma Linda, CA.
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Sianov A, Harders M. Exploring Feature-Based Learning for Data-Driven Haptic Rendering. IEEE TRANSACTIONS ON HAPTICS 2018; 11:388-399. [PMID: 29994158 DOI: 10.1109/toh.2018.2817483] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Abstract
In this work we extend ideas of machine learning to the domain of data-driven haptic rendering. The proposed approach facilitates the processing of high-dimensional haptic interaction signals, which so far proved too difficult for existing data-driven methods. The key idea is to construct a compact feature space in the frequency domain which allows for efficient data reduction via a feature selection process. First, in a recording stage, extensive force and displacement datasets are acquired in automated measurements on deformable sample objects. These data are then transformed into a dimensionally reduced, compact frequency space representation. Next, feature-based learning is carried out in this feature space to significantly reduce the size of the original dataset. Based on this, time-domain haptic models capable of real-time performance are finally generated to encode the forces arising from bimanual object interactions. The presented processing chain is generally applicable and extendable to more complex interactions with even higher-dimensional data. The resulting haptic models are directly usable for data-driven haptic rendering. We illustrate the improved performance in comparison with previously existing data-processing approaches.
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Chae S, Jung SW, Park HS. In vivo biomechanical measurement and haptic simulation of portal placement procedure in shoulder arthroscopic surgery. PLoS One 2018; 13:e0193736. [PMID: 29494691 PMCID: PMC5833274 DOI: 10.1371/journal.pone.0193736] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2017] [Accepted: 02/16/2018] [Indexed: 01/22/2023] Open
Abstract
A survey of 67 experienced orthopedic surgeons indicated that precise portal placement was the most important skill in arthroscopic surgery. However, none of the currently available virtual reality simulators include simulation / training in portal placement, including haptic feedback of the necessary puncture force. This study aimed to: (1) measure the in vivo force and stiffness during a portal placement procedure in an actual operating room and (2) implement active haptic simulation of a portal placement procedure using the measured in vivo data. We measured the force required for port placement and the stiffness of the joint capsule during portal placement procedures performed by an experienced arthroscopic surgeon. Based on the acquired mechanical property values, we developed a cable-driven active haptic simulator designed to train the portal placement skill and evaluated the validity of the simulated haptics. Ten patients diagnosed with rotator cuff tears were enrolled in this experiment. The maximum peak force and joint capsule stiffness during posterior portal placement procedures were 66.46 (±10.76N) and 2560.82(±252.92) N/m, respectively. We then designed an active haptic simulator using the acquired data. Our cable-driven mechanism structure had a friction force of 3.763 ± 0.341 N, less than 6% of the mean puncture force. Simulator performance was evaluated by comparing the target stiffness and force with the stiffness and force reproduced by the device. R-squared values were 0.998 for puncture force replication and 0.902 for stiffness replication, indicating that the in vivo data can be used to implement a realistic haptic simulator.
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Affiliation(s)
- Sanghoon Chae
- Graduate School of Medical Science and Engineering, Korea Advanced Institute of Science and Technology (KAIST), Daejeon, South Korea
| | - Sung-Weon Jung
- Department of Orthopaedic surgery, Samsung Changwon Hospital, Sungkyunkwan University School of Medicine, Changwon, South Korea
| | - Hyung-Soon Park
- Department of Mechanical Engineering, Korea Advanced Institute of Science and Technology (KAIST), Daejeon, South Korea
- * E-mail:
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Joddar B, Tasnim N, Thakur V, Kumar A, McCallum RW, Chattopadhyay M. Delivery of Mesenchymal Stem Cells from Gelatin-Alginate Hydrogels to Stomach Lumen for Treatment of Gastroparesis. Bioengineering (Basel) 2018; 5:E12. [PMID: 29414870 PMCID: PMC5874878 DOI: 10.3390/bioengineering5010012] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/04/2018] [Revised: 02/02/2018] [Accepted: 02/04/2018] [Indexed: 12/12/2022] Open
Abstract
Gastroparesis (GP) is associated with depletion of interstitial cells of Cajal (ICCs) and enteric neurons, which leads to pyloric dysfunction followed by severe nausea, vomiting and delayed gastric emptying. Regenerating these fundamental structures with mesenchymal stem cell (MSC) therapy would be helpful to restore gastric function in GP. MSCs have been successfully used in animal models of other gastrointestinal (GI) diseases, including colitis. However, no study has been performed with these cells on GP animals. In this study, we explored whether mouse MSCs can be delivered from a hydrogel scaffold to the luminal surfaces of mice stomach explants. Mouse MSCs were seeded atop alginate-gelatin, coated with poly-l-lysine. These cell-gel constructs were placed atop stomach explants facing the luminal side. MSCs grew uniformly all across the gel surface within 48 h. When placed atop the lumen of the stomach, MSCs migrated from the gels to the tissues, as confirmed by positive staining with vimentin and N-cadherin. Thus, the feasibility of transplanting a cell-gel construct to deliver stem cells in the stomach wall was successfully shown in a mice stomach explant model, thereby making a significant advance towards envisioning the transplantation of an entire tissue-engineered 'gastric patch' or 'microgels' with cells and growth factors.
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Affiliation(s)
- Binata Joddar
- Inspired Materials & Stem-Cell Based Tissue Engineering Laboratory (IMSTEL), Department of Metallurgical, Materials and Biomedical Engineering, University of Texas at El Paso, 500 W University Avenue, El Paso, TX 79968, USA.
- Border Biomedical Research Center, University of Texas at El Paso, 500 W University Avenue, El Paso, TX 79968, USA.
| | - Nishat Tasnim
- Inspired Materials & Stem-Cell Based Tissue Engineering Laboratory (IMSTEL), Department of Metallurgical, Materials and Biomedical Engineering, University of Texas at El Paso, 500 W University Avenue, El Paso, TX 79968, USA.
| | - Vikram Thakur
- Department of Biomedical Sciences, Center of Emphasis in Diabetes and Metabolism, Texas Tech University Health Sciences Center, 5001 El Paso Drive, El Paso, TX 79905, USA.
| | - Alok Kumar
- Inspired Materials & Stem-Cell Based Tissue Engineering Laboratory (IMSTEL), Department of Metallurgical, Materials and Biomedical Engineering, University of Texas at El Paso, 500 W University Avenue, El Paso, TX 79968, USA.
| | - Richard W McCallum
- Department of Internal Medicine, Paul L. Foster School of Medicine, Texas Tech University Health Sciences Center, 4800 Alberta Avenue, El Paso, TX 79905, USA.
| | - Munmun Chattopadhyay
- Department of Biomedical Sciences, Center of Emphasis in Diabetes and Metabolism, Texas Tech University Health Sciences Center, 5001 El Paso Drive, El Paso, TX 79905, USA.
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Gadomski BC, Shetye SS, Hindman BJ, Dexter F, Santoni BG, Todd MM, Traynelis VC, From RP, Fontes RB, Puttlitz CM. Intubation biomechanics: validation of a finite element model of cervical spine motion during endotracheal intubation in intact and injured conditions. J Neurosurg Spine 2018; 28:10-22. [DOI: 10.3171/2017.5.spine17189] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
OBJECTIVEBecause of limitations inherent to cadaver models of endotracheal intubation, the authors’ group developed a finite element (FE) model of the human cervical spine and spinal cord. Their aims were to 1) compare FE model predictions of intervertebral motion during intubation with intervertebral motion measured in patients with intact cervical spines and in cadavers with spine injuries at C-2 and C3–4 and 2) estimate spinal cord strains during intubation under these conditions.METHODSThe FE model was designed to replicate the properties of an intact (stable) spine in patients, C-2 injury (Type II odontoid fracture), and a severe C3–4 distractive-flexion injury from prior cadaver studies. The authors recorded the laryngoscope force values from 2 different laryngoscopes (Macintosh, high intubation force; Airtraq, low intubation force) used during the patient and cadaver intubation studies. FE-modeled motion was compared with experimentally measured motion, and corresponding cord strain values were calculated.RESULTSFE model predictions of intact intervertebral motions were comparable to motions measured in patients and in cadavers at occiput–C2. In intact subaxial segments, the FE model more closely predicted patient intervertebral motions than did cadavers. With C-2 injury, FE-predicted motions did not differ from cadaver measurements. With C3–4 injury, however, the FE model predicted greater motions than were measured in cadavers. FE model cord strains during intubation were greater for the Macintosh laryngoscope than the Airtraq laryngoscope but were comparable among the 3 conditions (intact, C-2 injury, and C3–4 injury).CONCLUSIONSThe FE model is comparable to patients and cadaver models in estimating occiput–C2 motion during intubation in both intact and injured conditions. The FE model may be superior to cadavers in predicting motions of subaxial segments in intact and injured conditions.
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Affiliation(s)
- Benjamin C. Gadomski
- 1Department of Mechanical Engineering, School of Biomedical Engineering, Orthopaedic Bioengineering Research Laboratory, Colorado State University, Fort Collins, Colorado
| | - Snehal S. Shetye
- 1Department of Mechanical Engineering, School of Biomedical Engineering, Orthopaedic Bioengineering Research Laboratory, Colorado State University, Fort Collins, Colorado
| | - Bradley J. Hindman
- 2Department of Anesthesia, University of Iowa Roy J. and Lucille A. Carver College of Medicine, Iowa City, Iowa
| | - Franklin Dexter
- 2Department of Anesthesia, University of Iowa Roy J. and Lucille A. Carver College of Medicine, Iowa City, Iowa
| | | | - Michael M. Todd
- 4Department of Anesthesia, University of Minnesota, Minneapolis, Minnesota; and
| | | | - Robert P. From
- 2Department of Anesthesia, University of Iowa Roy J. and Lucille A. Carver College of Medicine, Iowa City, Iowa
| | - Ricardo B. Fontes
- 5Department of Neurosurgery, Rush University Medical Center, Chicago, Illinois
| | - Christian M. Puttlitz
- 1Department of Mechanical Engineering, School of Biomedical Engineering, Orthopaedic Bioengineering Research Laboratory, Colorado State University, Fort Collins, Colorado
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Pfeifer CR, Alvey CM, Irianto J, Discher DE. Genome variation across cancers scales with tissue stiffness - an invasion-mutation mechanism and implications for immune cell infiltration. ACTA ACUST UNITED AC 2017; 2:103-114. [PMID: 29082336 DOI: 10.1016/j.coisb.2017.04.005] [Citation(s) in RCA: 34] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
Many different types of soft and solid tumors have now been sequenced, and meta-analyses suggest that genomic variation across tumors scales with the stiffness of the tumors' tissues of origin. The opinion expressed here is based on a review of current genomics data, and it considers multiple 'mechanogenomics' mechanisms to potentially explain this scaling of mutation rate with tissue stiffness. Since stiff solid tissues have higher density of fibrous collagen matrix, which should decrease tissue porosity, cancer cell proliferation could be affected and so could invasion into stiff tissues as the nucleus is squeezed sufficiently to enhance DNA damage. Diversification of a cancer genome after constricted migration is now clear. Understanding genome changes that give rise to neo-antigens is important to selection as well as to the development of immunotherapies, and we discuss engineered monocytes/macrophages as particularly relevant to understanding infiltration into solid tumors.
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Affiliation(s)
- Charlotte R Pfeifer
- Physical Sciences Oncology Center at Penn (PSOC@Penn), University of Pennsylvania, Philadelphia, PA 19104.,Molecular & Cell Biophysics Lab, University of Pennsylvania, Philadelphia, PA 19104.,Graduate Group / Department of Physics & Astronomy, University of Pennsylvania, Philadelphia, PA 19104
| | - Cory M Alvey
- Physical Sciences Oncology Center at Penn (PSOC@Penn), University of Pennsylvania, Philadelphia, PA 19104.,Molecular & Cell Biophysics Lab, University of Pennsylvania, Philadelphia, PA 19104.,Graduate Group / Department of Pharmacology, University of Pennsylvania, Philadelphia, PA 19104
| | - Jerome Irianto
- Physical Sciences Oncology Center at Penn (PSOC@Penn), University of Pennsylvania, Philadelphia, PA 19104.,Molecular & Cell Biophysics Lab, University of Pennsylvania, Philadelphia, PA 19104
| | - Dennis E Discher
- Physical Sciences Oncology Center at Penn (PSOC@Penn), University of Pennsylvania, Philadelphia, PA 19104.,Molecular & Cell Biophysics Lab, University of Pennsylvania, Philadelphia, PA 19104.,Graduate Group / Department of Physics & Astronomy, University of Pennsylvania, Philadelphia, PA 19104.,Graduate Group / Department of Pharmacology, University of Pennsylvania, Philadelphia, PA 19104
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Chandler JH, Mushtaq F, Moxley-Wyles B, West NP, Taylor GW, Culmer PR. Real-Time Assessment of Mechanical Tissue Trauma in Surgery. IEEE Trans Biomed Eng 2017; 64:2384-2393. [PMID: 28237916 DOI: 10.1109/tbme.2017.2664668] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Abstract
OBJECTIVE This work presents a method to assess and prevent tissue trauma in real-time during surgery. BACKGROUND Tissue trauma occurs routinely during laparoscopic surgery with potentially severe consequences. As such, it is crucial that a surgeon is able to regulate the pressure exerted by surgical instruments. We propose a novel method to assess the onset of tissue trauma by considering the mechanical response of tissue as it is loaded in real-time. METHODS We conducted a parametric study using a lab-based grasping model and differing load conditions. Mechanical stress-time data were analyzed to characterize the tissue response to grasps. Qualitative and quantitative histological analyses were performed to inspect damage characteristics of the tissue under different load conditions. These were correlated against the mechanical measures to identify the nature of trauma onset with respect to our predictive metric. RESULTS Results showed increasing tissue trauma with load and a strong correlation with the mechanical response of the tissue. Load rate and load history also showed a clear effect on tissue response. The proposed method for trauma assessment was effective in identifying damage. The metric can be normalized with respect to loading rate and history, making it feasible in the unconstrained environment of intraoperative surgery. SIGNIFICANCE This work demonstrates that tissue trauma can be predicted using mechanical measures in real-time. Applying this technique to laparoscopic tools has the potential to reduce unnecessary tissue trauma and its associated complications by indicating through user feedback or actively regulating the mechanical impact of surgical instruments.
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Afshari E, Rostami M, Farahmand F. Review on different experimental techniques developed for recording force-deformation behaviour of soft tissues; with a view to surgery simulation applications. J Med Eng Technol 2017; 41:257-274. [DOI: 10.1080/03091902.2016.1264492] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023]
Affiliation(s)
- Elnaz Afshari
- Biomechanics Department, Faculty of Biomedical Engineering, Amirkabir University of Technology (Tehran Polytechnic), Tehran, Iran
| | - Mostafa Rostami
- Biomechanics Department, Faculty of Biomedical Engineering, Amirkabir University of Technology (Tehran Polytechnic), Tehran, Iran
| | - Farzam Farahmand
- Mechanical Engineering Department, Sharif University of Technology, Tehran, Iran
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Li M, Miller K, Joldes GR, Kikinis R, Wittek A. Biomechanical model for computing deformations for whole-body image registration: A meshless approach. INTERNATIONAL JOURNAL FOR NUMERICAL METHODS IN BIOMEDICAL ENGINEERING 2016; 32:10.1002/cnm.2771. [PMID: 26791945 PMCID: PMC4956599 DOI: 10.1002/cnm.2771] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/23/2015] [Revised: 12/06/2015] [Accepted: 01/17/2016] [Indexed: 06/05/2023]
Abstract
Patient-specific biomechanical models have been advocated as a tool for predicting deformations of soft body organs/tissue for medical image registration (aligning two sets of images) when differences between the images are large. However, complex and irregular geometry of the body organs makes generation of patient-specific biomechanical models very time-consuming. Meshless discretisation has been proposed to solve this challenge. However, applications so far have been limited to 2D models and computing single organ deformations. In this study, 3D comprehensive patient-specific nonlinear biomechanical models implemented using meshless Total Lagrangian explicit dynamics algorithms are applied to predict a 3D deformation field for whole-body image registration. Unlike a conventional approach that requires dividing (segmenting) the image into non-overlapping constituents representing different organs/tissues, the mechanical properties are assigned using the fuzzy c-means algorithm without the image segmentation. Verification indicates that the deformations predicted using the proposed meshless approach are for practical purposes the same as those obtained using the previously validated finite element models. To quantitatively evaluate the accuracy of the predicted deformations, we determined the spatial misalignment between the registered (i.e. source images warped using the predicted deformations) and target images by computing the edge-based Hausdorff distance. The Hausdorff distance-based evaluation determines that our meshless models led to successful registration of the vast majority of the image features. Copyright © 2016 John Wiley & Sons, Ltd.
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Affiliation(s)
- Mao Li
- Intelligent Systems for Medicine Laboratory, School of Mechanical and Chemical Engineering, The University of Western Australia, Perth, Australia
| | - Karol Miller
- Intelligent Systems for Medicine Laboratory, School of Mechanical and Chemical Engineering, The University of Western Australia, Perth, Australia
- Institute of Mechanics and Advanced Materials, Cardiff School of Engineering, Cardiff University, Wales, UK
| | - Grand Roman Joldes
- Intelligent Systems for Medicine Laboratory, School of Mechanical and Chemical Engineering, The University of Western Australia, Perth, Australia
| | - Ron Kikinis
- Surgical Planning Laboratory, Brigham and Women’s Hospital, Harvard Medical School, Boston, MA, USA
- Fraunhofer Institute for Medical Image Computing MEVIS and the University of Bremen, Bremen, Germany
| | - Adam Wittek
- Intelligent Systems for Medicine Laboratory, School of Mechanical and Chemical Engineering, The University of Western Australia, Perth, Australia
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Abstract
BACKGROUND Patient safety during operations hinges on the surgeon's skills and abilities. However, surgical training has come under a variety of restrictions. To acquire dexterity with decreasingly "simple" cases, within the legislative time constraints and increasing expectations for surgical results is the future challenge. OBJECTIVES Are there alternatives to traditional master-apprentice learning? MATERIALS AND METHODS A literature review and analysis of the development, implementation, and evaluation of surgical simulation are presented. RESULTS Simulation, using a variety of methods, most important physical and virtual (computer-generated) models, provides a safe environment to practice basic and advanced skills without endangering patients. These environments have specific strengths and weaknesses. CONCLUSIONS Simulations can only serve to decrease the slope of learning curves, but cannot be a substitute for the real situation. Thus, they have to be an integral part of a comprehensive training curriculum. Our surgical societies have to take up that challenge to ensure the training of future generations.
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Affiliation(s)
- A Nabavi
- Klink für Neurochirurgie, International Neuroscience Institute (INI) Hannover GmbH, Rudolf-Pichlmayr-Straße 4, 30625, Hannover, Deutschland.
| | - J Schipper
- Klinik für Hals-Nasen-Ohrenheilkunde, Zentrum für Operative Medizin II, Universitätsklinikum Düsseldorf, Düsseldorf, Deutschland
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Seok J, Oh CT, Kwon HJ, Kwon TR, Choi EJ, Choi SY, Mun SK, Han SH, Kim BJ, Kim MN. Investigating skin penetration depth and shape following needle-free injection at different pressures: A cadaveric study. Lasers Surg Med 2016; 48:624-8. [PMID: 27075398 DOI: 10.1002/lsm.22517] [Citation(s) in RCA: 40] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 03/20/2016] [Indexed: 11/09/2022]
Abstract
BACKGROUND AND OBJECTIVES The effectiveness of needle-free injection devices in neocollagenesis for treating extended skin planes is an area of active research. It is anticipated that needle-free injection systems will not only be used to inject vaccines or insulin, but will also greatly aid skin rejuvenation when used to inject aesthetic materials such as hyaluronic acid, botulinum toxin, and placental extracts. There has not been any specific research to date examining how materials penetrate the skin when a needle-free injection device is used. In this study, we investigated how material infiltrates the skin when it is injected into a cadaver using a needle-free device. STUDY DESIGN/MATERIALS AND METHODS Using a needle-free injector (INNOJECTOR™; Amore Pacific, Seoul, Korea), 0.2 ml of 5% methylene blue (MB) or latex was injected into cheeks of human cadavers. The device has a nozzle diameter of 100 µm and produces a jet with velocity of 180 m/s. This jet penetrates the skin and delivers medicine intradermally via liquid propelled by compressed gasses. Materials were injected at pressures of 6 or 8.5 bars, and the injection areas were excised after the procedure. The excised areas were observed visually and with a phototrichogram to investigate the size, infiltration depth, and shape of the hole created on the skin. A small part of the area that was excised was magnified and stained with H&E (×40) for histological examination. RESULTS We characterized the shape, size, and depth of skin infiltration following injection of 5% MB or latex into cadaver cheeks using a needle-free injection device at various pressure settings. Under visual inspection, the injection at 6 bars created semi-circle-shaped hole that penetrated half the depth of the excised tissue, while injection at 8.5 bars created a cylinder-shaped hole that spanned the entire depth of the excised tissue. More specific measurements were collected using phototrichogram imaging. The shape of the injection entry point was consistently spherical regardless of the amount of pressure used. When injecting 5% MB at 6 bars, the depth of infiltration reached 2.323 mm, while that at 8.5 bars reached 8.906 mm. The area of the hole created by the 5% MB injection was 0.797 mm(2) at 6 bars and 0.242 mm(2) at 8.5 bars. Latex injections reached a depth of 3.480 mm at 6 bars and 7.558 mm at 8.5 bars, and the areas were measured at 1.043 mm(2) (6 bars) and 0.355 mm(2) (8.5 bars). Histological examination showed that the injection penetrated as deep as the superficial musculoaponeurotic system at 6 bars and the masseter muscle at 8.5 bars. CONCLUSION When injecting material into the skin using a pneumatic needle-free injector, higher-pressure injections result in a hole with smaller area than lower-pressure injections. The depth and shape of skin penetration vary according to the amount of pressure applied. For materials of low density and viscosity, there is a greater difference in penetration depth according to the degree of pressure. Lasers Surg. Med. 48:624-628, 2016. © 2016 Wiley Periodicals, Inc.
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Affiliation(s)
- Joon Seok
- Department of Dermatology, Chung-Ang University College of Medicine, Seoul, Korea
| | - Chang Taek Oh
- Department of Medicine, Graduate School, Chung-Ang University, Seoul, South Korea
| | - Hyun Jung Kwon
- Department of Dermatology, Chung-Ang University College of Medicine, Seoul, Korea
| | - Tae Rin Kwon
- Department of Medicine, Graduate School, Chung-Ang University, Seoul, South Korea
| | - Eun Ja Choi
- Department of Medicine, Graduate School, Chung-Ang University, Seoul, South Korea
| | - Sun Young Choi
- Department of Dermatology, Chung-Ang University College of Medicine, Seoul, Korea
| | - Seog Kyun Mun
- Department of Otorhinolaryngology-Head and Neck Surgery, Chung-Ang University College of Medicine, Seoul, Korea
| | - Seung-Ho Han
- Department of Anatomy, Chung-Ang University College of Medicine, Seoul, Korea
| | - Beom Joon Kim
- Department of Dermatology, Chung-Ang University College of Medicine, Seoul, Korea
| | - Myeung Nam Kim
- Department of Dermatology, Chung-Ang University College of Medicine, Seoul, Korea
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Intubation Biomechanics: Laryngoscope Force and Cervical Spine Motion during Intubation in Cadavers-Cadavers versus Patients, the Effect of Repeated Intubations, and the Effect of Type II Odontoid Fracture on C1-C2 Motion. Anesthesiology 2016; 123:1042-58. [PMID: 26288267 DOI: 10.1097/aln.0000000000000830] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
BACKGROUND The aims of this study are to characterize (1) the cadaver intubation biomechanics, including the effect of repeated intubations, and (2) the relation between intubation force and the motion of an injured cervical segment. METHODS Fourteen cadavers were serially intubated using force-sensing Macintosh and Airtraq laryngoscopes in random order, with simultaneous cervical spine motion recorded with lateral fluoroscopy. Motion of the C1-C2 segment was measured in the intact and injured state (type II odontoid fracture). Injured C1-C2 motion was proportionately corrected for changes in intubation forces that occurred with repeated intubations. RESULTS Cadaver intubation biomechanics were comparable with those of patients in all parameters other than C2-C5 extension. In cadavers, intubation force (set 2/set 1 force ratio = 0.61; 95% CI, 0.46 to 0.81; P = 0.002) and Oc-C5 extension (set 2 - set 1 difference = -6.1 degrees; 95% CI, -11.4 to -0.9; P = 0.025) decreased with repeated intubations. In cadavers, C1-C2 extension did not differ (1) between intact and injured states; or (2) in the injured state, between laryngoscopes (with and without force correction). With force correction, in the injured state, C1-C2 subluxation was greater with the Airtraq (mean difference 2.8 mm; 95% CI, 0.7 to 4.9 mm; P = 0.004). CONCLUSIONS With limitations, cadavers may be clinically relevant models of intubation biomechanics and cervical spine motion. In the setting of a type II odontoid fracture, C1-C2 motion during intubation with either the Macintosh or the Airtraq does not appear to greatly exceed physiologic values or to have a high likelihood of hyperextension or direct cord compression.
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Full-surface deformation measurement of anisotropic tissues under indentation. Med Eng Phys 2015; 37:484-93. [PMID: 25857545 DOI: 10.1016/j.medengphy.2015.03.005] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/04/2014] [Revised: 03/17/2015] [Accepted: 03/17/2015] [Indexed: 11/20/2022]
Abstract
Inverse finite element-based analysis of soft biological tissues is an important tool to investigate their complex mechanical behavior and to develop physical models for medical simulations. Although there have recently been advances in dealing with the computational complexities of modeling biological materials, the collection of a sufficiently dense set of experimental data to properly capture their typically regionally varying properties still remains a critical issue. The aim of this work was to develop and test an optical system that combines 2D-Digital Image Correlation (DIC) and a novel Fringe Projection method with radial sensitivity (RFP) to test soft biological tissues under in vitro indentation. This system has the distinctive capability of using a single camera to retrieve the shape and 3D deformation of the whole upper surface of the indented sample without any blind measurement areas (with exception of the area under the indenter), with nominal depth and in-plane resolution of 0.05 mm and 0.004 mm, respectively. To test and illustrate the capabilities of the developed DIC/RFP system, the in vitro response to indentation of a homogeneous and isotropic latex foam is presented against the response of a slab of porcine ventricular myocardium, a highly in-homogeneous and anisotropic tissue. Our results illustrate the enhanced capabilities of the developed method to capture asymmetry in deformation with respect to standard indentation tests. This feature, together with the possibility of miniaturizing the system into a hand-held probe, makes this method potentially extendable to in vivo settings, alone or in combination with ultrasound measurements.
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Christensen MB, Oberg K, Wolchok JC. Tensile properties of the rectal and sigmoid colon: a comparative analysis of human and porcine tissue. SPRINGERPLUS 2015; 4:142. [PMID: 25977885 PMCID: PMC4414857 DOI: 10.1186/s40064-015-0922-x] [Citation(s) in RCA: 35] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 09/18/2014] [Accepted: 03/11/2015] [Indexed: 01/19/2023]
Abstract
For many patients, rectal catheters are an effective means to manage bowel incontinence. Unfortunately, the incidence of catheter leakage in these patients remains troublingly high. Matching the mechanical properties of the catheter and the surrounding tissue may improve the catheter seal and reduce leakage. However, little data is available on the mechanical properties of colorectal tissue. Therefore, our group examined the mechanical properties of colorectal tissue obtained from both a common animal model and humans. Uniaxial tension tests were performed to determine the effects of location, orientation, and species (porcine and human) on bowel tissue tensile mechanical properties. Bowel tissue ultimate strength, elongation at failure, and elastic modulus were derived from these tests and statistically analyzed. Ultimate tensile strength (0.58 MPa, 0.87 MPa), elongation at failure (113.19%, 62.81%), and elastic modulus (1.83 MPa, 5.18 MPa) for porcine and human samples respectively exhibited significant differences based on species. Generally, human tissues were stronger and less compliant than their porcine counterparts. Furthermore, harvest site location and testing orientation significantly affected several mechanical properties in porcine derived tissues, but very few in human tissues. The data suggests that porcine colorectal tissue does not accurately model human colorectal tissue mechanical properties. Ultimately, the tensile properties reported herein may be used to help guide the design of next generation rectal catheters with tissue mimetic properties, as well as aid in the development of physical and computer based bowel models.
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Affiliation(s)
- Michael B Christensen
- Keck Center for Tissue Engineering, Department of Bioengineering, University of Utah, 36 S Wasatch Dr. Rm 3100, Salt Lake City, UT 84112 USA
| | - Kevin Oberg
- Keck Center for Tissue Engineering, Department of Bioengineering, University of Utah, 36 S Wasatch Dr. Rm 3100, Salt Lake City, UT 84112 USA
| | - Jeffrey C Wolchok
- Department of Biomedical Engineering, University of Arkansas, 120 Engineering Hall, Fayetteville, AR 72701 USA
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Intubation biomechanics: laryngoscope force and cervical spine motion during intubation with Macintosh and Airtraq laryngoscopes. Anesthesiology 2014; 121:260-71. [PMID: 24739996 DOI: 10.1097/aln.0000000000000263] [Citation(s) in RCA: 46] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
INTRODUCTION Laryngoscopy and endotracheal intubation in the presence of cervical spine instability may put patients at risk of cervical cord injury. Nevertheless, the biomechanics of intubation (cervical spine motion as a function of applied force) have not been characterized. This study characterized and compared the relationship between laryngoscope force and cervical spine motion using two laryngoscopes hypothesized to differ in force. METHODS Fourteen adults undergoing elective surgery were intubated twice (Macintosh, Airtraq). During each intubation, laryngoscope force, cervical spine motion, and glottic view were recorded. Force and motion were referenced to a preintubation baseline (stage 1) and were characterized at three stages: stage 2 (laryngoscope introduction); stage 3 (best glottic view); and stage 4 (endotracheal tube in trachea). RESULTS Maximal force and motion occurred at stage 3 and differed between the Macintosh and Airtraq: (1) force: 48.8 ± 15.8 versus 10.4 ± 2.8 N, respectively, P = 0.0001; (2) occiput-C5 extension: 29.5 ± 8.5 versus 19.1 ± 8.7 degrees, respectively, P = 0.0023. Between stages 2 and 3, the motion/force ratio differed between Macintosh and Airtraq: 0.5 ± 0.2 versus 2.0 ± 1.4 degrees/N, respectively; P = 0.0006. DISCUSSION The relationship between laryngoscope force and cervical spine motion is: (1) nonlinear and (2) differs between laryngoscopes. Differences between laryngoscopes in motion/force relationships are likely due to: (1) laryngoscope-specific cervical extension needed for intubation, (2) laryngoscope-specific airway displacement/deformation needed for intubation, and (3) cervical spine and airway tissue viscoelastic properties. Cervical spine motion during endotracheal intubation is not directly proportional to force. Low-force laryngoscopes cannot be assumed to result in proportionally low cervical spine motion.
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Kurita Y, Ikeda A, Nagata K, Ogasawara T. Haptic Augmentation Utilizing the Reaction Force of a Base Object. JOURNAL OF ROBOTICS AND MECHATRONICS 2013. [DOI: 10.20965/jrm.2013.p0072] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
A haptic device is one of the interfaces promising as a human-computer interaction tool that provides users with information in a virtual reality environment. The proposed haptic augmentation presents the force response of an object by combining the force generated from a haptic device against the force response generated from the base object, which has material properties similar to those of the target object. In this paper, the concept of a haptic augmentation technique is described and the prototype of a haptic augmentation system is developed. Frequency characteristics and experiments by human participants show that the proposed method has better performance than a traditional device-only method.
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Small intestine mucosal adhesivity to in vivo capsule robot materials. J Mech Behav Biomed Mater 2012; 15:24-32. [DOI: 10.1016/j.jmbbm.2012.06.018] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/18/2012] [Revised: 06/18/2012] [Accepted: 06/28/2012] [Indexed: 11/20/2022]
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Bourgouin S, Bège T, Masson C, Arnoux PJ, Mancini J, Garcia S, Brunet C, Berdah SV. Biomechanical characterisation of fresh and cadaverous human small intestine: applications for abdominal trauma. Med Biol Eng Comput 2012; 50:1279-88. [PMID: 23054381 DOI: 10.1007/s11517-012-0964-y] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/14/2012] [Accepted: 09/25/2012] [Indexed: 11/26/2022]
Abstract
Intestinal injuries are responsible for significant morbidity and mortality arising from trauma to the abdomen. The biomechanical characterisation of the small intestine allows for the understanding of the pathophysiological mechanisms responsible for these injuries. Studies reported in the literature focus principally on quasi-static tests, which do not take into account the stresses experienced during high kinetic trauma. In addition, the use of embalmed human tissue can alter the recorded response. The stress-strain curves from 43 tensile tests performed at 1 m/s were analysed. Samples were prepared from four fresh human intestines and from four embalmed cadaveric intestines. The data indicated a two-phase response, with each response consisting of a quasi-linear increase in the stress followed by an inflection in the curve before a peak preceding the loss of stress. The fresh tissue was more deformable than the embalmed tissue, and its first peak stress was lower (P = 0.034). A complementary histological analysis was performed. The results of the analysis enable an investigation of the response of the intestinal wall layers to stress as a two-layer structure and highlight the high sensitivity of the structure's mechanical behaviour to the speed of loading and the method of preservation.
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Terry BS, Schoen JA, Rentschler ME. Characterization and Experimental Results of a Novel Sensor for Measuring the Contact Force From Myenteric Contractions. IEEE Trans Biomed Eng 2012; 59:1971-7. [DOI: 10.1109/tbme.2012.2195179] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
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Barone WR, Feola AJ, Moalli PA, Abramowitch SD. THE EFFECT OF PREGNANCY AND POSTPARTUM RECOVERY ON THE VISCOELASTIC BEHAVIOR OF THE RAT CERVIX. J MECH MED BIOL 2012; 12:12500091-125000917. [PMID: 23125473 DOI: 10.1142/s0219519412004399] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
The objective of this study was to elucidate the normal functional adaptations of the cervix in pregnancy. Utilizing a Long-Evans rodent model, the cervix was divided into distal and proximal portions for virgin, mid-pregnant, and four weeks postpartum animals. The quasi-linear viscoelastic theory describes the elastic and viscous behavior of the cervix. A hydroxyproline assay was used to measure collagen content. The nonlinearity of the elastic response significantly increased throughout the entire cervix during pregnancy when compared to virgin samples (p < 0.05) and was similar to virgin samples postpartum. All viscous behavior, except for the short-term relaxation of the proximal cervix, significantly differed for pregnant specimens (p < 0.05) and remained similar to pregnant samples postpartum. Collagen content was found to increase by mid-pregnancy only in the proximal cervix when compared to virgin. Distal and proximal portions, however, were found to differ in collagen content at all time points (p < 0.05). This study finds that the cervix becomes elastically stiffer with increasing strain and exhibits increased viscous behavior during pregnancy, with incomplete recovery postpartum. These alterations allow for quick dissipation of loads, and are likely related to altered matrix organization and porosity reported by others.
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Affiliation(s)
- William R Barone
- Musculoskeletal Research Center, Department of Bioengineering University of Pittsburgh, 405 Center for Bioengineering, 300 Technology Drive, Pittsburgh Pennsylvania 15219, USA
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Danion F, Diamond JS, Flanagan JR. The role of haptic feedback when manipulating nonrigid objects. J Neurophysiol 2011; 107:433-41. [PMID: 22013237 DOI: 10.1152/jn.00738.2011] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Humans can learn to manipulate objects with complex dynamics, including nonrigid objects with internal degrees of freedom. The first aim of this study was to assess the contribution of haptic feedback when learning to manipulate a nonrigid object. The second aim was to evaluate how learning without haptic feedback influences subsequent learning with haptic feedback and vice versa. The task involved moving a simulated mass-attached to a grasped handle via a simulated, damped spring-to a target as quickly as possible. In the haptic plus vision (HV) condition, appropriate forces were applied to the handle, which was attached to a robot. In the vision only (V) condition, these forces were turned off. Participants completed 80 trials in each condition, with one-half starting with the HV condition. Both groups exhibited significant learning, as measured by movement time, in both conditions. For the condition performed first, initial performance, learning rate, and final performance were better with haptic feedback. Prior experience in the HV condition led to faster learning and better final performance in the V condition. However, prior experience in the V condition led to slower learning and worse final performance in the HV condition. In the V condition, all participants tended to keep the mass close to the hand. In the HV condition, participants who started with the HV condition allowed the mass to move away from the hand, whereas participants who started with the V condition continued to keep the mass close to the hand. We conclude that haptic feedback as well as prior experience with haptic feedback enhance the ability to control nonrigid objects and that training without haptic feedback can lead to persisting detrimental effects when subsequently dealing with haptic feedback.
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Affiliation(s)
- Frédéric Danion
- Institute of Movement Sciences, 163 Ave. de Luminy, 13009 Marseille, France.
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Basafa E, Farahmand F. Real-time simulation of the nonlinear visco-elastic deformations of soft tissues. Int J Comput Assist Radiol Surg 2010; 6:297-307. [PMID: 20607618 DOI: 10.1007/s11548-010-0508-6] [Citation(s) in RCA: 48] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/10/2010] [Accepted: 06/14/2010] [Indexed: 11/30/2022]
Abstract
PURPOSE Mass-spring-damper (MSD) models are often used for real-time surgery simulation due to their fast response and fairly realistic deformation replication. An improved real time simulation model of soft tissue deformation due to a laparoscopic surgical indenter was developed and tested. METHOD The mechanical realization of conventional MSD models was improved using nonlinear springs and nodal dampers, while their high computational efficiency was maintained using an adapted implicit integration algorithm. New practical algorithms for model parameter tuning, collision detection, and simulation were incorporated. RESULTS The model was able to replicate complex biological soft tissue mechanical properties under large deformations, i.e., the nonlinear and viscoelastic behaviors. The simulated response of the model after tuning of its parameters to the experimental data of a deer liver sample, closely tracked the reference data with high correlation and maximum relative differences of less than 5 and 10%, for the tuning and testing data sets respectively. Finally, implementation of the proposed model and algorithms in a graphical environment resulted in a real-time simulation with update rates of 150 Hz for interactive deformation and haptic manipulation, and 30 Hz for visual rendering. CONCLUSION The proposed real time simulation model of soft tissue deformation due to a laparoscopic surgical indenter was efficient, realistic, and accurate in ex vivo testing. This model is a suitable candidate for testing in vivo during laparoscopic surgery.
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Affiliation(s)
- Ehsan Basafa
- School of Mechanical Engineering, Sharif University of Technology, Azadi Avenue, Tehran, Iran
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Electroactive Elastomeric Haptic Displays of Organ Motility and Tissue Compliance for Medical Training and Surgical Force Feedback. IEEE Trans Biomed Eng 2009; 56:2327-30. [DOI: 10.1109/tbme.2009.2024691] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
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Maciel A, Halic T, Lu Z, Nedel LP, De S. Using the PhysX engine for physics-based virtual surgery with force feedback. Int J Med Robot 2009; 5:341-53. [PMID: 19449317 PMCID: PMC2810833 DOI: 10.1002/rcs.266] [Citation(s) in RCA: 56] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Abstract
BACKGROUND The development of modern surgical simulators is highly challenging, as they must support complex simulation environments. The demand for higher realism in such simulators has driven researchers to adopt physics-based models, which are computationally very demanding. This poses a major problem, since real-time interactions must permit graphical updates of 30 Hz and a much higher rate of 1 kHz for force feedback (haptics). Recently several physics engines have been developed which offer multi-physics simulation capabilities, including rigid and deformable bodies, cloth and fluids. While such physics engines provide unique opportunities for the development of surgical simulators, their higher latencies, compared to what is necessary for real-time graphics and haptics, offer significant barriers to their use in interactive simulation environments. METHODS In this work, we propose solutions to this problem and demonstrate how a multimodal surgical simulation environment may be developed based on NVIDIA's PhysX physics library. Hence, models that are undergoing relatively low-frequency updates in PhysX can exist in an environment that demands much higher frequency updates for haptics. We use a collision handling layer to interface between the physical response provided by PhysX and the haptic rendering device to provide both real-time tissue response and force feedback. RESULTS Our simulator integrates a bimanual haptic interface for force feedback and per-pixel shaders for graphics realism in real time. To demonstrate the effectiveness of our approach, we present the simulation of the laparoscopic adjustable gastric banding (LAGB) procedure as a case study. CONCLUSIONS To develop complex and realistic surgical trainers with realistic organ geometries and tissue properties demands stable physics-based deformation methods, which are not always compatible with the interaction level required for such trainers. We have shown that combining different modelling strategies for behaviour, collision and graphics is possible and desirable. Such multimodal environments enable suitable rates to simulate the major steps of the LAGB procedure.
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Affiliation(s)
- Anderson Maciel
- Instituto de Informática, Universidade Federal do Rio Grande do Sul, Porto Alegre, Brazil.
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Résultats préliminaires et perspectives de la modélisation dynamique pelvienne patient-spécifique. ACTA ACUST UNITED AC 2009. [DOI: 10.1007/s11608-009-0231-3] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023]
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