With the amputation technique, a distinction must be made between whether the amputation wound is closed immediately or only at a second operation. This is referred to as a closed or open operation. The open, so-called two-stage amputation, gained its importance especially in cases of war and catastrophe and can be associated with considerable disadvantages such as soft tissue and muscle retraction and drying of the bones. However, various drainage and vacuum techniques mean that it is rarely necessary to leave a residual limb completely open.
The most important principle in amputation is to preserve the limb as much as possible, since the longer the lever arm, the better the patient has control over his prosthesis. Unfortunately, this general rule is limited in certain situations. First the amputation height must be determined. In general, the amputation is performed through tissue that will heal satisfactorily and at a height where all pathologically altered parts are removed.
Lack of blood circulation
In the case of a lack of blood flow, the blood flow of the skin flaps is considered a more important criterion than the condition of the large vessels when determining the height. If joints are to be preserved and thus better mobility achieved, the tissue blood flow must be determined precisely. In the area of the leg or lower leg, the question is usually whether or not the knee joint can be preserved.
In addition to maintaining as much length as possible, it is also important to ensure that the residual limb can be covered with sufficiently normal sensitive and scar-free skin. This is because an insensitive or transplanted skin can barely withstand the pressure of a prosthesis and is very likely to fail. This problem mainly affects the lower limb, as it is heavily loaded.
But it is also a problem in traumatic injuries with burns and abrasions. An exception are children in whom a stump with an active growth joint (epiphyseal joint) is to be covered with skin, because in this case the skin grafts are less sensitive. It is also important that the residual limb is padded with muscle. Here, if the surgeon has difficulty suturing the opposing muscle groups above the bone without tension, he or she must shorten the bone to make the suture easier. Large vessels located in the muscle must be cut off individually when the muscles are severed, smaller vessels can be scabbed by heat.
In order to avoid the formation or the consequences of benign but painful nerve nodules (neuromas), which can occur when a nerve is severed, the nerve must be severed as close to the body as possible, otherwise compression of the neuroma by the prosthesis can lead to severe pain.