The Navy Prosthetics Research Laboratory impulsion valve.

PERSPIRATION of the stump while a prosthesis is being worn has always been a problem to a sizable segment of the amputee population. As a rule, amputees perspire at a greater rate than is normal even without the prosthesis. The newer, total-contact sockets as designed and introduced offer no provision for ventilation. Although in the case of some patients who sweat profusely during the initial use of total-contact sockets the problem seems to disappear after a period, there remains a sufficient number of cases in which perspiration presents a real problem. In an attempt to provide ventilation in sockets, many prosthetists have drilled or punched many small holes in the socket walls, but this has not proven to be very satisfactory. Because of the high concentration of sweat glands in the extremities (as many as 80 per square cm.), it is virtually impossible to provide mechanically a sufficient number of holes in a socket wall to give adequate ventilation and retain the necessary strength. To overcome this dilemma, porous plastic laminates (1, 2) that permitted breathing were developed. These have proven to be quite satisfactory for upper-extremity prostheses but much less so for lower-extremity sockets where strength is a paramount problem. Except in cases where the prosthesis is subjected to only light loads, when the socket walls are made thick enough to withstand the stresses imposed the socket becomes intolerably bulky. Because porous laminates offer an almost ideal solution, work is continuing on their refinement. Meanwhile, experiments and clinical experience indicate that the use of an inexpensive impulsion valve developed by the Navy Pros-