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Automated Framework for the Design of Passive Prosthetic & Orthotic Interfaces

Description:

TECHNOLOGY AREA(S): Bio Medical 

OBJECTIVE: Develop, demonstrate, and commercialize an automated and data-driven computational framework for the design and optimization of passive prosthetic & orthotic (P&O) interfaces. Such a framework will predict the equilibrium shape and compliant mechanical properties of an optimized P&O interface, enhancing user comfort, mitigating soft tissue injury, and ultimately, improving the quality of life for the P&O user. 

DESCRIPTION: Musculoskeletal injury is the leading cause of health problems for the military. It can be caused by traumatic combat injuries and physically straining risk factors such as military training, repeated combat deployment, carrying heavy loads, and standing for extended periods of time, walking long distances and participating in sports [1]. There have been over 1700 major limb amputations from the current conflicts with more than 82% of those affecting the lower extremity, with lower extremity involvement exceeding 95% of civilian amputations. Prosthetic and orthotic (P&O) interfaces are mechanical structures that form the interface between a P&O device and a tissue region which functions to appropriately transfer and distribute mechanical loads to couple the device to the tissue region without causing discomfort or injury. Residual-limb soft tissues are not designed to bear weight yet must endure large compression and shear forces from conventional prosthetic sockets, directly contributing to tissue injury [2]. Currently, P&O interface design is largely an artisan procedure performed by prosthetists and orthotists with varying experience. This conventional design process is also not standardized, and often does not include sufficient quantitative, patient-specific data. Hence, across P&O practitioners, discrepancies exist in the quality of P&O interfaces. The manual nature of the current design process does not lend itself to the inclusion of detailed biological data such as internal bone and soft tissue geometries, patient-specific biomechanical properties and loading data. Proposals are sought to develop a patient-specific, automated, and data-driven framework for the design and optimization of passive P&O interfaces. 

PHASE I: Demonstrate the feasibility of producing an advanced patient-specific, data-driven P&O interface design framework for the quantitative design and optimization of passive P&O interfaces. The required Phase I deliverables will include: 1) a research plan for engineering the quantitative design for the interface of a prosthesis, and 2) a preliminary prototype, either physical or virtual, to demonstrate the proof-of-concept capability of the design framework. Other supportive data may also be provided during this effort. Due to the short timeline of a Phase I project, human and animal use is not allowed. A Phase I project should demonstrate a proof of concept and/or efficacy of the design framework in handling computer-generated data. 

PHASE II: The performer shall design, develop, test, finalize and validate the practical implementation of the prototype system that implements the Phase I methodology. The testing and practical implementation of the prototype system should be relevant to Service members who have experienced limb trauma requiring the use of a prosthesis. These patients are often young and have previously demonstrated the need to perform Return to Duty, occupation, and other life activities which cannot be completed with sub-optimal P&O device interface fit. As such, all human use testing should be on individuals physiologically similar to the active duty population. The demonstration of prototype should show applicability to prosthetic and orthotic devices alike, regardless of manufacturer or whether those legs are passive or microprocessor controlled. The system should produce P&O device interfaces that also account for different activity specific devices such as running feet or high activity orthotic devices. 

PHASE III: The performer is encouraged to work with commercial partners (prosthetics manufacturers and amputee care providers) and military clinics (For example, a military treatment facility that treats patients with amputation. The three main centers include Walter Reed National Military Medical Center, San Antonio Military Medical Center, and the Naval Medical Center, San Diego) to develop a final commercial product that will allow prosthetists to develop an optimal design of passive prosthetic & orthotic interfaces.  

REFERENCES: 

1: Yancosek, K. E., Roy, T., & Erickson, M. (2012). Rehabilitation programs for musculoskeletal injuries in military personnel. Current Opinion in Rheumatology, 24(2), 232"236. doi:10.1097/BOR.0b013e3283503406

2:  Salawu, A., Middleton, C., Gilbertson, A., Kodavali, K. and Neumann, V. (2006). Stump ulcers and continued prosthetic limb use. Prosthetics and orthotics international, vol. 30, pp. 279-285.

KEYWORDS: Prosthetics, Orthotics, Socket, Design, Interface 

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