A computerized device for the volumetric analysis of the residual limbs of amputees

Prosthetics Research Study has developed a computerized automated system for the volumetric analysis of the residual limbs of amputees. Basically, this system utilizes the same principles as does normal, clinical fluid displacement volumetric analysis, with the addition of the following--if an object is suspended in a vertical cylinder into which water is being injected at a constant rate, then the rate of rise of the water will vary proportionally, at any point, with the cross-sectional area of the object. In this system, water is pumped into a Plexiglas cylinder of appropriate size so as to immerse a residual limb within a time frame of under ten seconds while a microcomputer records the water depth as a function of time. The rate of water depth rise is recorded for 256 levels during a measurement. These results are then analyzed comparatively, on a level-for-level basis, with similar rates generated with fluid pumped into the empty cylinder, thus generating 256 discrete cross-sectional-area parameters. These are then processed (in groups of eight) into 32 actual cross sections and displayed, graphed, or stored for purposes of comparison. Possible clinical application for this kind of device includes measurement of edema and other extremity volume changes with time, and measurement of muscle activity related to axial movements of muscle bulk.