Numerical Simulations and Experimental Data to Evaluate Residual Limb-Socket Interaction

Morotti, Roberto; Rizzi, Caterina; Regazzoni, Daniele; Colombo, Giorgio

doi:10.1115/imece2014-36860

Cited by 3 publications

(1 citation statement)

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“…Although patientspecific geometries are derived from MRI, the socket designs are created in a computer aided but manual fashion based on experience and a-priori knowledge of manually inspected vulnerable and load-bearing regions. In addition, the above has been combined with FEA based socket design evaluation [37], [38], and socket evaluation using FEA is also presented in [39]- [41]. However, in all of these cases the soft tissue material behavior was modeled using linear elasticity which is not appropriate for analysis of large deformations.…”

Section: Introductionmentioning

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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Section: Introductionmentioning

confidence: 99%

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

Moerman¹,

Sengeh²,

Herr³

2016

Preprint

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Design and Additive Manufacturing of Lower Limb Prosthetic Socket

Vitali

Regazzoni

Rizzi

et al. 2017

Volume 11: Systems, Design, and Complexity

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Additive Manufacturing (AM) is not only an innovative approach of fabrication but it fosters a new paradigm to design products. The possibility to confer inhomogeneous properties to the product provides an important design key. This paper concerns the design and manufacture of medical devices that require a high level of customization. We focus the attention on lower limb prosthesis and in particular on the prosthetic socket. The proposed method is centered on the virtual modeling of patient’s residual limb and the virtual process is highly integrated and the data flow is as fluid as possible. Three main phases can be identified: design, validation and manufacture of the socket. Firstly, the technician uses the Socket Modeling Assistant (SMA) tool to design the socket shape. Then, a numerical simulation is run to check pressure distribution and validate the socket shape. Finally, a multi-material 3D printer is used to build the socket. Preliminary results are presented and conclusions are drawn concerning the challenge of multi-material 3D printing of the socket.

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