e-AD: enhanced attachment device

A new attachment for trans-humeral amputees between a myoelectric prosthesis and a bone anchored implant system

Master thesis (2018)

Authors

L.E. van der Kaaden Industrial Design Engineering

Contributors

R.H.M. Goossens (mentor)
Y. Song (mentor)
E.L. Doubrovski (mentor)
J.P.W. Millenaar (mentor)
Faculty
Industrial Design Engineering, Industrial Design Engineering
Copyright: © 2018 Eefje van der Kaaden
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Published Date

21-08-2018

Language

English

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Faculty

Industrial Design Engineering

Abstract

The goal of Integrum is to improve the life of amputees. They do so by providing the OPRA (Osseointegrated prosthesis for the Rehabilitation of Amputees), bone-anchored implant systems for prosthetic attachment: a prosthesis can be mounted on a percutaneous abutment (‘pin’) coming from the residual limb. One of the latest developments of Integrum is the e-OPRA system, the enhanced-OPRA. The e-OPRA has implanted electrodes embedded in the bone anchored implant for the neural control of a myoelectric prosthesis. With the addition of the electronics, the requirements for the attachment of the prosthesis have changed: Along with the prosthesis being attached to the abutment, the electronics in the implant must be connected to the controller in the prosthesis. The connector in the abutment and the connector on the prosthesis side fit in only one way and must be aligned before they are connected. Misalignment can cause damage to the connectors and failure in the control of the prosthesis. The conventional OPRA attachment device is not sufficient for these changes. That is why the e-AD, the enhanced attachment device, is introduced.

The e-AD consist of an adapter mounted on the abutment, and a base and shaft mounted on the prosthesis. To attach the prosthesis, the abutment with adapter is inserted into the shaft. The alignment is ensured between the abutment and the base and the connection is ensured between the adapter and the shaft. The connection is made by a Bal Seal Canted Coil spring ®, according to the Lock and Quick Release (LQR®) principle: The adapter has two grooves on its outer surface and the shaft houses a Bal Seal Canted Coil spring ®. When the abutment with adapter is inserted into the shaft, the spring will lock in the first groove of the adapter and the abutment cannot be pulled out or pushed further. In this position, the prosthesis can be used in daily life. When wanting to detach the prosthesis, the user can rotate the shaft, unlocking it, and then pull it up. The spring will then snap into the second groove of the adapter, the spring is re-oriented and ‘relaxes’. The abutment can be lifted out of the prosthesis.