The common factors indicating amputation of a part of the body are trauma, interference with the vascular supply, malignant neoplasm, chronic osteomyelitis, life-threatening infections, inoperable congenital limb deformity in children, the need to increase function, and, occasionally, the cosmetic effect.
In the presence of trauma, it is first necessary to evaluate carefully the extent of tissue and vascular damage in terms of possibly salvaging the extremity. With the recent advances in peripheral vascular repair and grafting, reestablishment of distal blood flow following arterial injury, blockage by arteriosclerosis, or embolus is often possible. It is essential to combat shock with intravenous administration of fluids and colloid solutions until the patient's general condition is improved sufficiently to withstand the operation. With diabetes or advanced vascular disease, the usual strict medical measures are taken to regulate these associated diseases. If there is localized skin infection at the proposed level for amputation, the procedure is delayed whenever possible. In the presence of wet gangrene, packing the leg in ice or dry ice combined with the application of a tourniquet just below the site of proposed amputation not only may lessen toxicity but also may decrease the incidence of wound infection, since the lymphatics may be cleared before amputation. The threat of gas gangrene may be a real one when the arterial supply to the extremity has been severely compromised, either by intra-arterial occlusion or trauma with inadequate debridement and a closed space infection.
Spinal anesthesia is commonly used for major amputation of the lower extremities, inhalation anesthesia for major amputations of the upper extremities, and plexus block or local infiltration anesthesia for amputation of the fingers and toes.
(See Plate 231.) In amputations of the upper extremity, the patient is placed near the edge of the table with the arm extended and abducted to the desired position. For amputations of the lower extremity, the leg may be elevated with several sterile towels under the calf.
In the absence of infection, the extremity is elevated to encourage venous drainage before a tourniquet is applied. The tourniquet is placed above the knee for amputations of the lower leg and foot, high in the thigh for amputations of the knee and lower thigh, and above the elbow to control the brachial artery for major amputations of the forearm. In ...