| ??? 09/16/12 02:15 Read: times |
#188347 - other considerations Responding to: ???'s previous message |
Jim Granville said:
Richard Erlacher said:
... I'd point out that the limitation on precision is imposed by the size of the probes. The size is limited by the fact that accidents could cause injury if the probes are very small, even if the pressure is quite limited.
I would not consider moving the probe set while pressure is applied, due to the risk of tearing skin. I'm not sure whether it's more important to measure the probes' deflection concurrently or one-at-a-time. I'm also not sure whether it's more beneficial to measure the probes on a horizontal plane or a vertical one. Both have potential benefit. I'm not even certain that it would be better to use one probe or many. I did mention a nylon wheel on the probe end, to control area, and allow some sideways compliance, and movement. What I was considering was a sequence of move-extend-measure-retract-move. That would yield information about tissue density at predefined points, as the places between, particularly where the tissue is soft and very compliant, will move considerably when pressed. I'd tend to favour one probe, but if you really need to measure fast it comes down to just how fast swelling occurs. In my particular case, it proceeds at a pretty rapid rate, and nearly immediately, though I'm over 30-years post-op on the second amputation. A single probe would do a pressure contour sweep in a few seconds, but you would need multiple sweeps to get a full contour. I dislike the notion of moving with pressure applied, as even a wheel, unless the mechanism is very carefully built, could misalign and potentially damage the skin. If speed becomes vital, then that pushes you more to multiple probes, with full active pressure intelligence - and away from KISS.
I agree that simplicity would be a good thing. Patient safety is of paramount importance, though, particularly as many amputees are diabetic, and what takes 3 days or so for a healthy person to heal, often takes several weeks for a diabetic to heal, and that could mean he/she has to forgo wearing a prosthesis until it heals. That can be VERY inconvenient. RE |
