Musings of a Compulsive Thinker

Round-up of the pet project

Here's my summary of design issues for the plug-in prosthesis idea.

Really, this design concept isn't so far off. It's probably a long ways from bulk commercial production, because it's kind of an expensive prospect at this point, but the actual implementation is within our grasp.

The electromechanical functions of the prosthesis may be complicated, but this has all been done by robotics research groups focusing on control of biofidelic movement.

The interface linking the peripheral nerves to the prosthesis is a three-stage problem:

1. The "plug-in" interface on the prosthesis itself.
Comparatively speaking, this is trivial.

2. The direct tie-ins between the implanted cybernetic interface (ICI) and the nerves.
This is not so trivial. However, referring back to previous entries including research on the FINE (flat-interface nerve electrode), we can see that the groundwork for this stage is well underway.

3. The implantation and long-term maintenance of the ICI itself, the physical module that will interface mechanically with the body and the prosthesis.
This is probably the most difficult part of the entire design. I foresee three areas of primary concern:

A) Mechanically, this unit has to hold up under not-insignificant loading; it has to be firmly anchored in the limb, and it has to transmit forces between the limb end and the prosthetic. Ideally, it will perform as a nearly-seamless mechanical interface with little to no maintenance requirements, because repairs on this level will likely require surgical intervention.

B) Electrically, the ICI needs to maintain good contacts with the prosthesis. Over time, various elements may require replacement; this shouldn't be too much of a hassle.

C) Biologically, the ICI should not provoke any kind of long-term inflammatory or immune response. Here, it is important to recognize that the direct neural interface will require a permanent disruption in the body's natural coverings (skin, underlying connective tissues). On the biological side of the interface, at some point the natural and the synthetic will meet. Some questions here involve the extent of skin coverage -- will the skin be continuous over the end of the limb, or will it end at a seam along the edge of the ICI? If the skin is continuous, will it cover most of the ICI surface (in which case irritation will be a concern where the skin touches the prosthesis), or will the ICI fit over it like a cap (in which case irritation is still a concern)?

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Labels: engineering, science

posted by the alygator @ 9:39 AM