Highlights Of Va Contractual Research Program--Prosthetics

John O. Ess linger M.D.

From BPR 10-4 Fall 1965, Bulletin of Prosthetics Research, Prosthetic and Sensory Aids Service, Department of Medicine and Surgery, Veterans Administration, Washington, D.C. Reprinted with permission.

Animal experiments are continuing on passage of materials through the skin and attachment to bone. Methods to give pain-free end-weight-bearing on amputated bones are being developed as an interesting by-product both on this project and, as a result of it, under private auspices.

Semi-buried Vitallium mesh has been placed subcuticularly and allowed to protrude through the skin without problems for as much as a year and a half. Raveling of the mesh has been prevented, in some cases by fusing, and in others by coating with Teflon. Experiments have recently begun with Dacron mesh inserted subcuticularly.

In accordance with ideas advanced by several others, an experiment was begun several years ago looking toward a two-stage procedure for skeletal attachment of a prosthesis. A plastic plug was screwed into the amputated and tapped end of the tibia, and the skin was closed over the plug. The initial goal was to allow firm healing of the plug into the bone and to assure absence of infection. (The second stage was intended to provide a portion snapped over the end of the plug, passing through the skin, and allowing fastening to an external prosthesis.) The animal proved able to walk so comfortably on the healed skin covering the dome-like end of the plug after the first stage that this method of obtaining end-weight-bearing seemed worthy of further development.

Numerous similar experiments have been made with rigid plastic plugs or with Silastic RTV (room-temperature-vulcanizing) rubber in the distal medullary canal and forming a mushroom-like projection over the amputated end. (The latter, like the elastic heel pad of the Syme stump, seemed to provide cushioning.) To assure that the animal actually used the stump, the opposite leg was usually disarticulated at the hip.

Though most experiments have involved the tibia, some little experience has been gained at other levels. In one case seen during a site visit in July 1965 (a dog accidentally amputated by a power mower), Teflon plugs were placed in the amputated ends of the metatarsals; as a control, the similarly amputated ends of the metatarsals of the opposite paw initially were left unplugged. The animal walked most of the time on the paw with the plugged ends, only occasionally on that with unplugged bones. The skin under the plugged ends remained intact and became somewhat callused, while that under the unplugged ends was beginning to ulcerate. At the time of the visit, plugging of the metatarsals of the second paw in an attempt to heal ulceration and restore symmetry was being considered by Dr. Esslinger.

Dr. Charles Frantz of Grand Rapids, long an active participant in the Artificial Limb Program, became interested in the possibilities for treating the end of the bone without attempting to project through the skin. The goals would be to improve tolerance for end-weight-bearing in any amputee and to avoid need for surgical revision through the elimination of pain, and the prevention of fascia and skin perforation by overgrowth of bone (compared with soft tissue) in a growing child. With support of the Hartford Foundation, he began experiments which have now been taken over by his colleague, Dr. Alfred Swanson, at Blodgett Memorial Hospital, Grand Rapids, Michigan. A Silastic plug with mushroom end is placed in the amputated end of the bone. Recently, prefabricated molded plugs have been used. In addition to a number of experiments on dogs, a few human cases have been so treated. Initial results are encouraging.

John O. Ess linger M.D. is from Birmingham, Michigan