Topic Overview
The decision to have a limb amputated is difficult for the person and
his or her doctor. Many times, extensive measures have been tried to save the
limb. The major causes of amputation are
diabetes and/or
peripheral arterial disease that results in either
painful, poor limb function or
gangrene.
In general, amputation is recommended for:
- Gangrene with or without
infection.
- Unbearable pain when at rest.
- Nonhealing,
untreatable ulcers.
Tobacco use may be the most important factor in progressing to
amputation.
In doing the amputation, the surgeon seeks to remove all dead or
dying tissue. Goals of amputation are to relieve pain, encourage wound healing,
and increase a person's ability to carry out his or her daily activities.
Amputations and bypass grafting surgery may be planned at the same
time to achieve the best results. For example, a person who has gangrene may
have an amputation of part of the foot or leg while also having bypass
grafting in an attempt to preserve still-living tissue. In a person who is not
a candidate for revascularization or who has not had success with previous
bypass grafting attempts, amputation alone may be recommended for severe pain
at rest, nonhealing ulcers, and/or gangrene.
Preoperative issues in amputations
Preoperative care before amputation is similar to any major surgery.
A complete history and physical exam, routine lab tests, a chest
X-ray, and an
electrocardiogram (EKG or ECG) may be performed.
People with major medical problems, such as diabetes or heart, lung,
or kidney problems must be carefully assessed and their medical care optimized
before the operation. The importance of the preoperative evaluation cannot be
overemphasized. People who have amputations are often chronically or seriously
ill. And their risk of dying around the time of the operation as well as in the
following years is higher than for other people of the same age.
At which level should the amputation be done?
The appropriate amputation level depends on a number of factors,
including why the amputation is needed, the general health of the person, the
possibility for recovery and rehabilitation (rehab), and the probability of adequate
wound healing. The aim of an amputation is to remove all dead and dying tissue
while creating the most useful limb for recovery and rehab. It is very
important to make sure that an artificial limb, if desired, can be appropriately fitted.
A below-the-knee amputation is usually preferable. It provides
better mobility. Even if a person is very unlikely to be able to walk because
of their general health or other medical conditions, a below-the-knee
amputation provides for easier transfers and movement while in bed. Walking on
an above-the-knee prosthesis (artificial limb) requires a lot more
energy than walking on a below-the-knee prosthesis, although young, relatively
healthy people manage much better than older, more frail people do. But when a
below-the-knee amputation cannot be done, an above-the-knee amputation has
the advantage of easier healing.
Sometimes a bypass grafting operation may be done to allow a
below-knee amputation site to heal adequately. The most important thing in
deciding whether a below-knee amputation will heal is the clinical judgment of
a knowledgeable surgeon.
When is the right time to operate?
In general, amputations for sudden ischemia (when a clot develops and
completely blocks blood supply to an extremity) are done to control pain
soon after the preoperative evaluation is finished, if possible.
Bypass surgery or angioplasty is always done when possible.
Amputation is the last option.
Noninfected gangrene of the fingers and toes can be treated by
amputation or can be allowed to "autoamputate" (tissue dies and sloughs off on
its own) over a period of time, usually months. Gangrene of other extremities
requires amputation.
Infected gangrene should be treated with the goal of getting rid of
the infection yet preserving as much of the extremity as possible. Dead or
dying infected tissue should be removed (debridement) as quickly as possible.
Tissue that is infected but may likely heal should be left. And the person
should receive intravenous antibiotics.
If a person is not stable or does not respond to antibiotic treatment
and debridement, amputation must be done rapidly. A first emergency
amputation is often done with the goal of stabilizing the person. And a
second elective operation may be done to remove any further dead tissue and to improve the function of the remaining
limb.