How To Determine The Appropriate Level Of Amputation

By Kathleen Satterfield, DPM

   One should not view an amputation as a failure but as an opportunity to give a patient a chance to improve his or her quality of life.1-3 If the amputation is a definitive procedure, it may allow the patient freedom from the continuing wound care that chronic ulcerations tend to require. While the amputation is often thought of as a simple procedure, one should only perform this procedure after careful consideration of factors that will lead to a successful long-term outcome for each patient.

   Selecting an inappropriate level of amputation can doom a procedure to failure from the start, even if the surgeon has performed the technical aspects of the surgery flawlessly. The pre-planning of a successful procedure should, in fact, comprise the majority of effort in a well-performed amputation.4

   Surgeons must weigh many considerations in order to successfully plan the appropriate level of amputation. These factors include: tissue viability (the presence of ulcerations, skin anomalies, tissue deficits); micro- and macro-vascular circulation; anatomy and biomechanical function (residual deformities); cardiac demand and energy expenditure; and rehabilitation potential.

Tissue Viability: Why It Is Essential To Evaluate For Possible Infection

   While it is of paramount importance to leave only viable tissue when performing an amputation, it is not always an easy call to make. The decision to leave “marginal” tissue has been the cause of many failed surgeries. Infection, ulcerations, necrosis and fibrotic tissue or dysvascular tissue can all predispose the surgery to fail. A failed amputation can mean the need for revision and exposing the compromised patient to further risk of anesthesia.2

   There is an inherent desire on the part of the surgeon, and indeed the patient, to leave as much length as possible during an amputation. However, leaving even any question of potentially infected tissue within the wound is inadvisable and foolhardy. That said, identifying affected tissue can be difficult in cases that are marginal.5-7

   There are some important signs to consider when evaluating patients. Strep infections, which are most destructive to tissue of all origins, cause hemorrhagic changes that are clearly visible as dark red, maroon and/or black color changes to connective tissues, blood vessels and muscle tissue.

   Staph infections may be more commonly represented by purulence. While the adjacent tissue may not have become compromised, it is necessary in this case to perform an atraumatic exploration of all potential spaces for further presence of infection. This is a learned skill that requires considerable caution and care. By exploring adjacent spaces, the surgeon may inadvertently spread infection. It is important to not only have an ingress into a compartment, but also to have an egress to allow for drainage of potentially infected materials.8-10

   It is imperative to visualize all tissue that may have been contiguous with known areas of infection. Under pressure, infectious fluids will extrude from one compartment to the next along anatomic lines.11, 12

   Van Baal states in Clinics of Infectious Disease that “Proper debridement and drainage of the infection requires a sound knowledge of foot anatomy. The usual routes of progression of the infection along anatomic pathways must be understood.”13 Reviewing the compartments of the foot will aid both novice and experienced surgeons in ensuring a knowledgeable exploration of potential areas of infection progression.

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