Management of Amputations

Background

Replantation attempts (with rare success) have been described for hundreds of years but the ability to consistently replant amputated parts is now possible with advances in microvascular surgical techniques. Upper limb and hand replants were first described in 1962. The first successful microvascular anastomosis of a digital vessel was described in 1965, and now replantation success rates range from 50% to 90%. Survival of the replanted tissue was the criterion for success for the original pioneers in replant surgery, but with further technological and surgical refinements, today's surgeons emphasize functional recovery as well as viability. Replantation of a part that is painful or useless or that interferes with function is a disservice to the patient and is less desirable than early restoration of function without replantation. With advancements in technology, there are also alternatives to replantation such as targeted reinnervation, transplantation of composite tissue, or the potential for upper extremity transplantation to restore upper extremity function. The operative plan must be tailored to each individual patient with consideration of the patient's underlying health, ability to undergo and comply with rehabilitation, support network, and likely functional outcome.

Indications

The mechanism of injury is the most important determinant of implant survival. Replantation is more likely to occur with sharp/penetrating injury, distal level of amputation, lack of multilevel involvement, and when the injury is isolated to the extremity. Preservation of the amputated part is indicated whenever there is a potential for replantation. Revascularization and reanastomosis of partially and completely amputated parts should be provided when there is hope of preservation or restoration of function. Aesthetic considerations, patient avocations, and occasionally the patient's religious or social customs may also influence the decision to proceed with surgery. Ultimately, the microsurgical team and patient must reach the decision together after a rational explanation of the potential results.

Replantation is more commonly performed for upper extremity amputation because a lower extremity prosthesis often provides a good functional outcome and is often superior to outcomes with replantation. Upper extremity prostheses are less able to achieve fine motor activity and a “bad hand” may be more functional than a “good amputation” in the upper extremity. Additionally, there is less muscle (which is less vulnerable to crush injury and allows a longer ischemia time) and increased collateral circulation in the upper extremity, which improves replantation success. Review Box 47.1 summarizes the general indications for replantation. Single-digit amputations that are both proximal to the distal interphalangeal (DIP) joint and distal to the flexor digitorum superficialis may be replanted successfully with good functional recovery ( Fig. 47.1 ). The thumb accounts for 40% to 50% of hand function with its utility in pinch and grip. Even if a replanted thumb has a limited range of motion, it is more functional than any other available reconstructive procedure or prosthetic device. The underlying health of the patient is more important to outcomes than chronologic age. Children consistently have better outcomes due to their superior neuroplasticity, regenerative capacity, and adaptability to rehabilitation, though there are no fixed age limits for replantation. The decision to replant is made on a case-by-case basis by the microsurgical team, who must weigh all the factors involved. In general, patients can expect to achieve 50% of original sensation and motor function of the replanted part, with younger patients and more distal amputations having the best outcomes.

Contraindications

Absolute contraindications to replantation include life-threatening injury or significant comorbidity that prohibits a lengthy operation. Relative contraindications include severely crushed or mangled parts or profuse contamination. Contraindications to replantation are listed in Review Box 47.1 and are discussed in the following sections. The amputated part should be treated carefully because portions may be used as a graft even if the entire part will not be replanted. For example, an amputated fingertip not suitable for replantation may be an ideal donor source for a skin graft on the stump. In addition, even when replantation is contraindicated, tissue (e.g., skin, bone, tendon) from the amputated part may be useful in restoring function to other damaged parts. In general, never discard amputated tissue until all possible uses of the severed parts are considered.

General Considerations

Patient Assessment and Management

The initial care and treatment of a patient with a traumatic amputation begins with a primary survey and stabilization of the airway, breathing, and circulation. Traumatic limb amputations are less likely to occur in isolation and management of a patient's injuries must be prioritized such that life-threatening head and torso injuries take precedence over limb-threatening conditions ( Fig. 47.2 ). Early hemorrhage control is essential. Bleeding should be controlled initially with direct pressure. If unsuccessful, the judicious use of a tourniquet is endorsed as a temporary adjunct to control extremity hemorrhage. To minimize potential complications, note the time of tourniquet application and limit tourniquet use to the time necessary to control the hemorrhage. Multiple amputations are an independent risk factor for death.

After the initial assessment and stabilization of the patient, initiate care of the stump and amputated part ( Box 47.1 ). A thorough neurovascular exam should be performed and documented. Evaluate the extremities for pulses and the presence of a bruit. In partial amputations, note the hard and soft signs of vascular injury ( Table 47.1 ). In patients with soft signs of vascular injury, measure the ankle-brachial index or arterial pressure index (systolic pressure of the injured extremity/systolic pressure of the uninjured extremity). A ratio of less than or equal to 0.9 raises concern for a vascular injury. Reduce and immobilize associated fractures and evaluate the patient for associated conditions such as rhabdomyolysis and compartment syndrome.