TECHNOLOGY AREA(S): Biomedical
OBJECTIVE: To develop a preliminary framework for a bio mathematical model to explain how human tissues interact / behave at their boundaries; develop a mathematical framework for translating this tissue interaction / behavior into predictive mathematical / biomechanical models able to represent tissue property transitions (e.g. muscle to tendon/ligament), aggregated tissues (connective, epithelial, muscular, and nervous), and systems of tissues/organ properties and behaviors. Demonstrate how this proposed work product is scalable and flexible and can be augmented for future use in medical simulation applications. The long term goal of this effort is to create a high fidelity, validated, reliable, robust, and reproducible simulated tissue interaction model for used by the medical research, development, and training community in products such as virtual reality part task trainers, interventional simulation systems, and to inform research and development of other dynamic interactive anatomical models.
DESCRIPTION: Patients demand that their healthcare providers appropriately and accurately diagnose and treat their ailments. To address this level of diagnosis and treatment, medical simulation researchers and developers must continue to advance training and education products by designing improved fidelity simulated tissues. However, incomplete information about human tissue properties and unrealistic simulated tissue behavior have been identified as knowledge and technology gaps by both civilian and military leaders; in addition, some inaccurate properties and behaviors may even have an adverse impact on medical training outcomes. Tissue interaction properties (e.g. tensile, shear, friction, and so forth) of connective, epithelial, muscular, and nervous tissue including sub-components of each of these broad categories lack fidelity in current simulation systems. While some basic tissue properties are known, the breadth and quantity of data remains insufficient for the development of mathematical models able to produce the life-like interactions of aggregated tissues and human organs for use in medical simulation and training systems.
With the advent of open-source frameworks for medical simulation and other computational methods for mechanistic mathematical modeling of biological interfaces at the cellular scale, emphasis on multi-scale modeling methods in biological and medical applications, and recent work in assessing medical simulation deformable models now is the time to begin developing a new or improved integrated multi-scale biophysical mathematical medical models to represent the interactions of aggregated tissues and organs for implementation in medical simulation systems; especially to support virtual and augmented reality applications.
These biophysical mathematical models could then be used for virtual reality, manikin-based, and/or hybrid medical simulation systems. This research and development effort aims to enable future military healthcare personnel to practice the skills and procedures needed to provide safe and effective care prior to practicing on humans. Inputs to considered for inclusion but are not limited to biomechanical engineering, physiology, computational mathematics, mathematical modeling, and clinical research, in order to (1) define, describe, and validate tissue interaction properties and characteristics such as friction, elasticity, cut strength, tensile strength, shear force, torque / torsion, hydration, dielectric properties, and thermal properties in reticular connective tissue, adipose tissue, cartilage, bone, fascia, blood, epithelium, stratified epithelium, striated, smooth and cardiac skeletal tissue, and peripheral nervous tissues; and (2) formulate and create a mathematical framework based upon the biophysical properties which balance individual components as they relate to aggregated tissues/organs; and (3) demonstrate the viability of the framework for developing a comprehensive, aggregated tissue and organ model. These capabilities should be as open source as possible, require a low / no manpower footprint, and be a tool that can be self-sustaining and extensible for wide variety of military and civilian uses.
PHASE I: Required Phase I proof of concept and report will include:
Provide a detailed description of the preliminary algorithm(s) and method(s) used to calculate the forces of interaction (anatomy/anatomy or tool/anatomy forces of interaction);
Define and describe tissue interaction properties and characteristics: for example, but not limited to the following, frictional forces, shear and tensile forces, adherence, the effect of hydration, temperature, electrolytes, and inflammation;
Provide references of all external data used and analyzed information of internally driven data;
Provide a preliminary plan describing the methodologies to be used to validate the biophysical mathematical model;
Provide information in the Phase I final report that described known gaps or inconsistencies in the proposed bio mathematical model, which would increase the risk to any extension of this work to Phase II.
PHASE II: At the end of Phase II, it is expected that prototype system be demonstrated. Tissue interaction model should be demonstrated through the use of an interactive software application. To provide a basis for future expansion, Phase II development should focus on the modeling dissection and exploration of vessels (artery and veins) such at the iliac, femoral, brachial, or carotid sites. Use of an accurately simulated dissecting tool (such as a Maryland dissector / curved dissector) to interact with the modeled tissues is desired within the interactive software application. It is intended that further development would be able to leverage the existing biophysical mathematical model for military injury point of care or civilian trauma surgery use cases. Additional deliverables include, but not limited to:
Demonstrate the mathematical / biophysical tissue model based upon the appropriate tissue properties into an integrated prototype;
During Phase II an In Progress Review may be conducted in the Washington DC, northern VA, and Maryland area. Attendance could be in person or via tele/video-conference and is usually held during the 2nd year of Phase II.
Documentation / reports detailing the integrated biophysical mathematical model. Plans for additional development are required for completion of the advanced prototype system;
Detailed documentation / report describing the open-source components (if any) of the proposed system;
Detailed documentation / report of the tissue interaction property / characteristic data and information that was used to create the model;
Provide in a document / report any and all required software dependencies and minimum computer hardware specifications required to run the partially integrated biophysical mathematical model;
Provide in a document / report any and all preliminary pilot data / information used to validate / verify predicted outcomes of the model. Provide the conditions and variables under which the tests were performed including preliminary data analysis and descriptions of known short-comings and provide plans for future mitigation / correction;
Provide in a document / report human subject, animal, or cadaver approvals that were performed during the research such as acquisition of data / information to create the model or during the pilot test study; &
If included, video appendices must comply with the following specifications:
Maximum run length: <= 6 minutes
Audio codec: AAC
Sample audio bit rate: 64 kbit/s (mono acceptable)
Video codec: H.264
Format: MPEG-4 (mp4) container
Accepted formats: (mov, avi, mpg, mpeg, mp4, wmv)
PHASE III DUAL USE APPLICATIONS: It is anticipated by the end of Phase III, that a transition ready biophysical mathematical tissue interaction model is made available. Provide in a document / report the probable life cycle management of such a fully integrated biophysical mathematical model including probable updates, maintenance costs, service related costs, and warranties. Provide anticipated cost per unit. The Phase III must provide documentation and reports of the "end-state" of the research. There must be at least one description of military applications and detailed plans must be provided in form of documents to fully explain the remaining research needed to that of an operational capability. Commercial applications OR one or more commercial technologies that could be potentially inserted into defense systems as a result of this research and development must also be proposed in the form of a document or report. Test and evaluation results of studies must be provided in a document or report (as well as the conditions under which the tests were conducted).
REFERENCES:
Maurel W. 3D modeling of the human upper limb including the biomechanics of joint, muscles and soft tissues. PhD thesis. Lausanne; 1999
Langelaan, MLP. The essence of biophysical cues in skeletal muscle tissue engineering. Technische Universiteit Eindhoven; 2010
Causin, P.; Sacco, R.; Verri, M.; A multiscale approach in the computational modeling of the biophysical environment in artificial cartilage tissue regeneration. Biomech Model Mechanobiol (2013) 12:763–780
Ambrosi, D.; Garikipati, K.; Kuhl, E.; Mini-Workshop: The mathematics of growth & remodelling of soft biological tissues. MATHEMATISCHES FORSCHUNGSINSTITUT OBERWOLFACH; August 31st – September 6th, 2008
Edwards, C.; Marks, R.; Evaluation of Biomechanical Properties of Human Skin. Clinics in Dermatology; 1995;13:375-380
Marchal, M.; Allard, J.; Duriez, C., Cotin, S.; Towards a Framework for Assessing Deformable Models in Medical Simulation. ISBMS '08 Proceedings of the 4th international symposium on Biomedical Simulation. Pages 176 – 184
McKee, C.; Last, J.; Russell, P.; Murphy, C.; Indentation Versus Tensile Measurements of Young’s Modulus for Soft Biological Tissues. TISSUE ENGINEERING: Part B; Volume 17, Number 3, 2011
KEYWORDS: Medical modeling; computational modeling; tissue interaction; aggregated tissues; multi-scale modeling; virtual reality; augmented reality; biomechanical simulation; deformable models
TPOC-1: Hugh Connacher
Phone: 301-619-8089
Email: hugh.i.connacher.civ@mail.mil
TPOC-2: Dr. Kevin Kunkler
Phone: 301-619-7931
Email: kevin.j.kunkler.civ@mail.mil
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