ISNY Flexible Sockets for Upper-Limb Prostheses

SIDNEY FISHMAN, PHD, NORMAN BERGER, MS, ANDJOAN EDELSTEIN, MA, PT


The ISNY (Iceland-Sweden-New York University) flexible socket system which has proven so successful in above-knee and, more recently, below-knee applications has been extended to upper-limb prostheses. Several patients with upper-limb amputation, including long and very short below-elbow, elbow disarticulation, and above-elbow limb loss have been fitted with prostheses having ISNY sockets. Various suspension designs have been used.

The fabrication and fitting protocol requires that the amputation limb be casted in the usual manner and the positive model modified conventionally. Very thin polyethylene is vacuum formed over the model to create a total contact, flexible socket which is nested in a rigid carbon-fiber reinforced frame. Double-sided adhesive tape secures the socket to the frame. For juvenile amputees, the frames are made slightly longer and the distal end filled with polyurethane foam which can be ground away later to enlarge the socket to accommodate growth. Wearers report improved comfort, better function, and more secure suspension with the thin, pliable socket. Fitting is expedited substantially by the translucency of the socket. Models of designs for various amputation levels are shown.

New York University Post-Graduate Medical School, 317 East 34th Street, New York NY 10016