Unfortunately, not all limbs that exhibit diabetic foot infections or ulcerations are able to be salvaged. There are instances where amputation of a toe, foot, or below knee amputation is actually in the patient's best interest. "Best interest" can include saving their life.
There is a multitude of considerations that must be addressed in the decision of a diabetic amputation. The situation will vary from patient to patient. Different amputation levels offer different advantages and disadvantages.
Patient preference of course is part of the equation, but in an ideal situation the patient would be happiest with the least amount of amputation. Many times this is possible, however, in a large percentage of cases this is not possible.
Ability of the wound to heal beyond the patient's preference, other considerations include the ability of the wound to heal. The level of diabetic amputation chosen must give the patient the best chance of healing, otherwise, the patient is once again looking at a chronic wound that requires regular ongoing medical care with the inability of the patient to get on with their life. Perhaps worse than that, it sets the patient up for possible further amputations at a higher level. So once again the patient is faced with more surgery along with the risks of surgery. Keep in mind that many diabetics are sick people with heart and kidney disease and the re-introduction of general anesthesia, along with the stress of surgery is not in the best interest to the patient.
Osteomyelitis In patients with osteomyelitis the amputation needs to be far enough away from the infected bone in order to avoid a "new" bone infection.
Vascular status The patient's vascular status (circulation) must be assessed. If the level of anticipated diabetic amputation does not exhibit adequate blood flow than the proposed procedure is doomed to failure before it begins. Without adequate circulation the surgical wound that is created will not heal. Any proposed skin flaps will also not heal. Blood is what allows wounds to heal. Too little blood equals no wound healing. This will lead to post operative complications. Again, the worse scenario is performing an amputation at a level that is poorly vascularized as it will ultimately require a second surgery.
Overall patient health The overall health and return to a somewhat normal life need to be addressed. A sedentary patient will place far less demands on the amputated limb than the reasonably young individual who would like to return to their normal activity level which usually includes participation in athletic activities. In those who hope to return to an active lifestyle the level of diabetic amputation becomes crucial. Because an amputation changes the biomechanical considerations in gait, sometimes an amputation further up may afford the patient a prosthesis that will better function in a more active lifestyle.
Even though in this case the psychological and cosmetic factors would suggest a lesser amputation, the desired lifestyle the patient hopes to resume would necessitate a more aggressive amputation in an effort to construct a prosthesis to allow the patient to resume his or her activity level. In this scenario the patient's vision of the future outweighs the medical criteria in terms of what level to do an amputation.
On the other end of the spectrum is the patient facing an amputation who is more sickly. Not only do they have a foot wound or infection that shows no signs of healing, but their overall health status is also a concern. These types of patients are usually poorly controlled diabetics. They also in many cases exhibit heart disease and kidney disease. Many will have nutritional deficiencies. If a person is malnourished, their tissues will not heal and any proposed procedure is doomed to failure. Malnutrition will also inhibit those whose limbs are being salvaged by wound care teams.
Many people with chronic foot wounds have been dealing with this problem for months if not years. They are seen constantly in wound care centers, occasionally hospitalized with infections and other diabetic related problems. The longer a wound is open with the inability to close it, the greater the chances it will never close. A chronic open wound is always susceptible to infection. If the blood sugars are always elevated the chance of infection and the inability to eradicate the infection also increases.
There are also scenarios where a patient has a foot wound that finally closes, the patient is discharged, only to return a few months or a year or two later with a new wound in the same location. Yes, closing the wound should be the initial treatment of choice, but inevitably if the wound keeps recurring and the doctor and patient cannot identify things the patient may be doing to himself (poor fitting shoes, poor hygiene, poor diet) that is causing recurring wounds, then again, amputation should at least be in the discussion.
Off-loading or reducing pressure on the wounded foot puts greater demands on the unaffected foot. This in many instances will cause eventual breakdown somewhere on the good foot and now the problem has doubled. For this reason, many patients reach a tipping point where they are better off with an amputation rather than an endless schedule of doctor's appointments and wound care treatment at home.
I think it is fairly safe to say that given the choice no one would like an amputation of their limb, however, there are instances where there is no choice. A septic (infected) foot can lead to death. In the less severe scenarios people in discussion with their doctor should arrive at a realistic decision as to what measures will allow them to get back to the type of lifestyle they envision for themselves. As you can see from this discussion there is no "cookie cutter" formula.
For those who suffer from diabetic ulcers or undergo lower extremity amputations there is the additional issue of mortality. Not so much from the ulcer or amputation itself, but rather from the underlying medical issues that lead up to these problems (or the inability to salvage a limb due to underlying causes), the life expectancy of a diabetic is very much diminished, more so if both limbs are amputated. If you look at the graph below, you will see that five year survival is less then some of the more common cancers.
Once again this the reason diabetics, even those diabetics who have no symptoms, need to take their disease seriously. It is much easier to prevent an ulcer or amputation then it is to cure one.
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