Development and validation of a 3D-printed interfacial stress sensor for prosthetic applications

Laszczak, Piotr; Jiang, Liudi; Bader, Dan L.; Moser, David; Zahedi, Saeed

doi:10.1016/j.medengphy.2014.10.002

Cited by 122 publications

(93 citation statements)

References 15 publications

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“…bed-or wheel chair-ridden patients) as well as for prosthetics wearers where optimising comfort at the stump-prosthetic interface and preventing pressure ulcers is critical [17,48,49]. These experimental techniques and tools offer vast opportunities to be complemented by computational studies to gain a more mechanistic understanding of the interplay between the physical factors that contribute to primary skin injuries and that can ultimately evolve into more serious conditions such as chronic wounds [5,9,50].…”

Section: Discussionmentioning

confidence: 99%

“…12 illustrate how the risk of damage initiation (correlated with high shear stress) varies according to the contact conditions at specific topographic and internal microstructural features of the skin and how far an "idealised" distribution of shear stress might be from that naturally occurring in real in vivo conditions. To date, experimental studies have analysed interfacial shear stress as a surrogate in vivo measure of the risk of developing skin injuries [16][17][18]. Nevertheless, these studies do not provide a quantitative insight into how these stresses are transmitted from the surface to the deeper layers of the skin.…”

Section: Discussionmentioning

confidence: 99%

“…It is known that repetitive loading of skin, especially under shear, results in skin lesions such as friction blisters [15]. Also, prolonged application of pressure can result in skin and deep tissue damage (pressure ulcers), which is aggravated when combined with interfacial shear [16][17][18]. In these situations, the interfacial properties of the skin and counter surface (e.g.…”

Section: Introductionmentioning

confidence: 99%

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Implications of Multi-asperity Contact for Shear Stress Distribution in the Viable Epidermis – An Image-based Finite Element Study

et al. 2017

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Understanding load transfer mechanisms from the surface of the skin to its deeper layers is crucial in gaining a fundamental insight into damage phenomena related to skin tears, blisters and superficial/deep tissue ulcers. It is unknown how shear stresses in the viable epidermis are conditioned by the skin surface topography and internal microstructure and to which extent their propagation is conditioned by the size of a contacting asperities.In this computational study, these questions were addressed by conducting a series of contact finite element analyses simulating normal indentation of an anatomically-based two-dimensional multi-layer model of the skin by rigid indenters of various sizes and sliding of these indenters over the skin surface. Indentation depths, local (i.e. microscopic) coefficients of friction and Young's modulus of the stratum corneum were also varied. For comparison purpose and for isolating effects arising purely from the skin microstructure, a geometrically-idealised equivalent multi-layer model of the skin was also considered.The multi-asperity contact induced by the skin topographic features in combination with a non-idealised geometry of the skin layers lead to levels of shear stresses much higher than those produced in the geometrically-idealised case. These effects are also modulated by other system parameters (e.g. local coefficient of friction, indenter radius).These findings have major implications for the design and analyses of finite element studies aiming at modelling the tribology of skin, particularly if the focus is on how surface shear stress leads to damage initiation which is a process known to occur across several length scales.

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Section: Discussionmentioning

confidence: 99%

Section: Discussionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Implications of Multi-asperity Contact for Shear Stress Distribution in the Viable Epidermis – An Image-based Finite Element Study

et al. 2017

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“…see [67]) and printable sensor designs have also been proposed (e.g. [68]). Motion capture systems may also be employed to study and capture dynamic loading data which may serve as input for load evaluation and validation.…”

Section: Discussionmentioning

confidence: 99%

Automated and Data-driven Computational Design of Patient-Specific Biomechanical Interfaces

Moerman¹,

Sengeh²,

Herr³

2016

Preprint

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Abstract-Biomechanical interfaces are mechanical structures that form the connection between a device and a tissue region, and, through appropriate load transfer, aim to minimize tissue discomfort and injury. A patient-specific and data-driven computational framework for the automated design of biomechanical interfaces is presented here. Optimization of the design of biomechanical interfaces is complex since it is affected by the interplay of the geometry and mechanical properties of both the tissue and the interface. The proposed framework is presented for the application of transtibial amputee prostheses where the interface is formed by a prosthetic liner and socket. Conventional socket design and manufacturing is largely artisan, non-standard, and insufficiently data-driven, leading to discrepancies between the quality of sockets produced by different prosthetists. Furthermore, current prosthetic liners are often not patient-specific. The proposed framework involves: A) non-invasive imaging to record patient geometry, B) indentation to assess tissue mechanical properties, C) data-driven and automated creation of patientspecific designs, D) patient-specific finite element analysis (FEA) and design evaluation, and finally E) computer aided manufacturing. Uniquely, the FEA procedure controls both the design and mechanical properties of the devices, and simulates, not only the loading during use, but also the pre-load induced by the donning of both the liner and the socket independently. Through FEA evaluation, detailed information on internal and external tissue loading, which are directly responsible for discomfort and injury, are available. Further, these provide quantitative evidence on the implications of design choices, e.g. : 1) alterations in the design can be used to locally enhance or reduce tissue loading, 2) compliant features can aid in relieving local surface pressure. The proposed methods form a patient-specific, data-driven and repeatable design framework for biomechanical interfaces, and by enabling FEA-based optimization reduces the requirement for repeated patient involvement in the currently manual and iterative design process.

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“…25 72 74 90 96 108 The skin suffers from abrasion, adding to the discomfort and potential for infection. 108 These problems persist in 20% to 55% of LL amputees no matter how good we optimize the socket design.…”

Section: Introductionmentioning

confidence: 99%

Review: Problems with Use of Trans-Tibial Prosthesis

Chatterjee¹,

Majumder²,

Roy-Chowdhury³

et al. 2016

j med imaging hlth inform

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Discomfort and elevated energy consumption is still a common companion of many prosthetic users, generally due to altered loading condition which the body is not adapted to, preventing them to participate actively in the society. The socket, being an interface between body and prosthesis, is believed to be the most important concern regarding comfort of prosthetic use. The main cause of problem is altered gait dynamics. Local stress concentration, friction and slippage, confinement into warm moist environment inside socket, etc. adds to discomfort. The stump, being a living part, is also subjected to variations. These produce various soft tissue problems and enhance energy expenditure. This can be somewhat countered by even distribution of load along stump. In this review article, papers regarding biomechanics and pathomechanics of prosthetic gait, the mechanical and corresponding medical problems and suggested solutions have been studied in details. 59% of Trans-Tibial amputees and 78% of Trans-Femoral amputees are found to have problems with socket fit. This results in skin irritations in 41% of TT amputees and 22% of TF amputees. The main problems are regional stress concentration, friction and rubbing of stump along socket and energy expenditure. Hydrostatic total surface bearing and variable geometry fitting socket has been hypothesized to counter this problem though they are also having their own limitations.

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Development and validation of a 3D-printed interfacial stress sensor for prosthetic applications

Cited by 122 publications

References 15 publications

Implications of Multi-asperity Contact for Shear Stress Distribution in the Viable Epidermis – An Image-based Finite Element Study

Implications of Multi-asperity Contact for Shear Stress Distribution in the Viable Epidermis – An Image-based Finite Element Study

Automated and Data-driven Computational Design of Patient-Specific Biomechanical Interfaces

Review: Problems with Use of Trans-Tibial Prosthesis

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