Elbow and Above-Elbow Amputations Periprocedural Care

Clinical presentation

Patients with vascular compromise or occlusion present very differently, depending on the etiology. For example, patients with vascular occlusion secondary to acute embolic phenomena from a more proximal arterial graft typically present with a cold, pale, initially painful portion of the upper extremity with absent capillary refill.

Because of collateral circulation, the location of embolic occlusion is often difficult to determine on the basis of clinical appearance. In such individuals, arteriography or magnetic resonance angiography (MRA) confirms the location of the occlusion and assists in determining the level of intervention. In persons with acute occlusion, medical or surgical thrombolytic recanalization or vascular bypass efforts should be pursued. However, if these efforts fail or if the devascularized tissue has undergone irreversible injury, then amputation is indicated.

Incidents of chronic ischemia, such as in persons with diabetes or peripheral vascular disease, occur less often in the upper extremity than in the lower extremity. Furthermore, the incidence of chronic ischemia resulting in amputations above the elbow is uncommon, given the relative size of the vessel and the proximity to the heart. Revascularization efforts in this situation are less successful and frequently proceed to amputation. Chronic ischemic injury begins distally and usually progresses proximally to more viable tissue. For this reason, the extent of ischemic injury may not be fully appreciated soon after the initiation of clinical changes.

In individuals with chronic vascular insufficiency, patients remain quite functional for many years despite intermittent reports of mild pain with activity or cold intolerance. The only skin changes, if any, may be those of atrophy (shiny hairless skin). For example, patients may present with acute onset of pain in the ipsilateral index and long digits with no or minimal skin discoloration acutely. Over the course of 24-72 hours, skin usually turns cyanotic, and pain is replaced with decreased sensation. Provided that the patient is not acutely ill from sepsis, amputation at this time is discouraged. In persons with chronic ischemia, allowing the extent of the ischemia to declare itself clinically is far preferable.

Cyanotic fingers may turn black with time, and assumed viable tissue more proximally may follow, with cyanosis observed in the fingers. Once the progression of ischemia has stabilized, plans for definitive amputation may commence. If the level of amputation is in question, specific tests may be performed to assess the viability and healing potential of the tissue in question.

Thermal burns and frostbite rarely result in amputation more proximal to the hand. However, with extensive injury, amputation may be required. In general, thermal burns and frostbite injuries should be managed nonoperatively until the extent of the damage can be assessed accurately and the amputation can be performed at the most distal level consistent with good healing. Pyrophosphate nuclear scanning has been demonstrated to be useful in predicting the need for amputation in these situations. ^[13]

Even in the trauma setting, the level of amputation may be difficult to determine. Most cases of trauma involve significant avulsion and crush components that leave obvious devitalized tissue exposed. The complete extent of the injury zone may not be apparent on initial presentation. When in doubt, especially in grossly contaminated wounds, it is wise to proceed with open amputation to allow the wound to declare itself prior to closure over a definitive stump length.

Neglected compartment syndromes in the upper extremities commonly necessitate amputation. Initially, fasciotomies are performed, and provided that the patient remains systemically stable, initial debridement should remove tissue that is obviously dead. Tissue that is neither contractile nor bleeding should be removed at this time. Tissue that is noncontractile but bleeding and that otherwise appears to be healthy should be left intact; fasciotomies should be left open and have a sterile dressing that prevents desiccation.

The patient should then return to the operating room within 24-48 hours for a second observation of the tissues, and the tissues should be debrided as described above. This conservative process continues until the tissues have stabilized and the surgeon is convinced that all remaining tissue is viable. Although this stepwise conservative debridement is labor-intensive, it ensures that the absolute minimal tissue has been removed and that the patient is left with maximal function.

Even in severe instances where amputation is indicated, this stepwise process dictates the level of amputation and ensures maximum length for the remaining portion of the extremity; otherwise, an arbitrary guess at the amputation level may be necessary, possibly leaving the remainder of the extremity inappropriately long (resulting in failure of healing) or inappropriately short (resulting in decreased functional potential). However, the stepwise process is contraindicated in patients with systemic sepsis, renal compromise secondary to disseminated myoglobin, or some other critical illness that leaves the patient unable to sustain multiple surgeries.

Laboratory studies

Hematocrit and hemoglobin levels should be monitored. In trauma situations, acute blood loss is a concern. Even with elective amputations, postoperative bleeding and hematoma formation require careful assessment. Acceptable levels are individualized on the basis of age, associated medical problems and injuries, and baseline values. In general, a young, otherwise healthy patient should maintain a hematocrit above 20% and a hemoglobin level higher than 6 g/dL. Elderly patients or patients with underlying cardiovascular disease should be maintained at higher levels (30% and 10 g/dL).

Creatinine levels should be monitored. In individuals with muscle injury and necrosis, myoglobin enters the systemic circulation and can lead to renal insufficiency and failure. This is especially true in individuals with thermal and electrical burns. If creatinine levels continue to rise more than 0.4 over baseline, preoperative, or preinjury levels, more aggressive surgical intervention and fluid hydration should be considered.

Potassium and calcium levels should be monitored. As dead tissue is metabolized, destroyed cells release intracellular stores of potassium and calcium into the extracellular space. Elevated levels of these electrolytes may lead to cardiac arrhythmias and seizures.

The white blood cell (WBC) count, C-reactive protein (CRP) level, and erythrocyte sedimentation rate (ESR) should be monitored in persons with infection. It is helpful to observe that these values normalize following amputation, thus suggesting resolution of the infection. The laboratory CRP value is typically the first to respond to treatment; the other two may take several days to weeks to normalize despite eradication of the infection. If these values remain elevated or rise further, treatment should be reassessed by changing to a more appropriate antibiotic, by searching for an unrelated occult infection or hidden abscess, and possibly by performing revision amputation at a more proximal level.

Platelets should be monitored periodically if subcutaneous heparin is administered postoperatively. Heparin-induced thrombocytopenia may occur even as a result of small subcutaneous doses of heparin.

Imaging studies

Plain radiography should be routinely included in preoperative planning. The presence of hardware, occult pathology, or other unanticipated abnormalities in an extremity to be amputated may affect the surgical plan.

In oncology cases, preoperative computed tomography (CT) and magnetic resonance imaging (MRI) have proved invaluable in assessing the extent of tumor involvement and level of amputation. When a forequarter amputation is considered in the treatment of a malignancy, CT and MRI should include not only the affected extremity but also the lungs. Occasionally, preoperative CT or MRI is helpful in evaluating the extent of infection and abscess in these particular settings.

Arteriography remains the standard for the definitive analysis of vascular status. However, because this is an invasive procedure, arteriography carries the risk of leading to a pseudoaneurysm, hematoma, and vascular embolism in the patient.

MRA remains a noninvasive alternative to arteriography. It avoids the complications of arterial puncture, eliminates the risk of contrast-related renal failure, and has a higher sensitivity than does contrast angiography in the identification of severe peripheral arterial occlusive disease.

Pyrophosphate nuclear scanning has been introduced as another noninvasive method of evaluating tissue viability. It has been demonstrated to be a useful adjunct in predicting the need for amputation in persons whose extremities have been damaged by electrical injury, frostbite, or invasive infection. Pyrophosphate nuclear scanning has a sensitivity of 94%, a specificity of 100%, and an accuracy of 96% when performed for this purpose.

Doppler ultrasonography (US) detects blood flow, and when employed in conjunction with blood pressure cuffs, it can be used to measure arterial pressure at different levels in the upper extremity.

Other studies

Transcutaneous oxygen tensions reflect tissue perfusion. Significant occlusive disease causes these measurements to fall below 35 mm Hg. In considering the level of amputation, it is imperative that transcutaneous oxygen tensions at the level of incision be at least 35 mm Hg, because measurements below this level are associated with decreased healing and wound problems. Measurement of tissue oxygen tension is not affected by incompressible, calcified vessels and appears to be very sensitive in evaluating arterial occlusive disease during exercise.

The time for prosthetic fitting in a person with an upper-extremity amputation has been debated. Traditionally, fitting commences once stump shrinkage has subsided, usually after 8-12 weeks. However, many have advocated immediate or early prosthetic fitting to improve outcome, particularly with regard to early bimanual activities and user rates.

Malone et al described a "golden period" of prosthetic fitting, which occurs within the first month following amputation of the upper extremity; according to the authors, fitting during this period maximizes prosthetic acceptance rates and use patterns among patients, regardless of the type of prosthesis that is initially employed. ^[14]

Malone et al also observed that if the fitting occurred within this time, patients demonstrated decreased edema, decreased postoperative pain, decreased phantom pain, accelerated wound healing, improved rehabilitation, and decreased hospital stays, compared with patients who underwent later fittings. ^[14] These benefits were less pronounced at amputation levels above the elbow but were still significant.

Unlike patients with a lower-extremity amputation, most persons with an upper-extremity amputation have excellent vascularity in their stump and are much less prone to wound-related problems. It appears that in the upper extremities, the advantages of immediate or early prosthetic fitting far outweigh the disadvantages.