Replantation in Emergency Medicine Treatment & Management

Updated: Feb 04, 2020
  • Author: Mark I Langdorf, MD, FAAEM, FACEP, MHPE, RDMS; Chief Editor: Harris Gellman, MD  more...
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Treatment

Prehospital Care

At the scene, collect and preserve all amputated parts, even those crushed and not thought to be useful. Parts not suitable for replantation can provide tendons or bone.

Cool the amputated part to 4°C to preserve it; 1 hour of warm ischemia is equivalent to approximately 6 hours of cold ischemia. Hence, cooling can markedly prolong the window of opportunity for replantation or revascularization. An amputated digit, for example, can withstand up to 30 hours of cold ischemia.

For cooling, wrap the part in saline-soaked gauze and then in a towel. Next, place it in a dry, plastic bag. Place this bag on ice, or in a second bag filled with ice and water, as soon as possible. This 2-layer approach avoids submersion of the part in ice water, which causes freezing of the tissues and cell destruction. Dry ice is too cold and causes tissue freezing and cell destruction. [15]

Estimate the blood lost at the scene; this information is useful regarding resuscitation prior to surgery. Control bleeding from the amputated stump.

Label the bag with the patient’s information. [16, 17]

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Emergency Department Care

Uncontrolled arterial bleeding is the only immediately life-threatening complication likely to be encountered in the ED after injury to the upper extremity. Normal hemostasis involves circumferential constriction of affected arteries and their retraction into the amputated stump. The addition of a pressure dressing usually suffices to control bleeding. With partial arterial lacerations, retraction is prevented, and bleeding control can be more difficult.

Control hemorrhage in the upper extremities with local direct pressure or a pressure dressing. Use of a proximal tourniquet is acceptable, although not preferred, if direct pressure is not effective. The surgeon can clamp and ligate a bleeding vessel, but this can complicate later repair. In the ED, point control with localized pressure over the bleeding vessel or use of a pressure dressing is preferred.

Elevate the arm. Ensure that a poorly applied pressure dressing does not become a tourniquet and cause ischemia in the amputated stump. If a tourniquet is used, use it as briefly as possible, perhaps only during resuscitation for acute hypovolemia. Use of a tourniquet for more than 3 hours may lead to irreversible loss of function. Do not use a tourniquet during an interhospital transfer. A consultant may appropriately use a temporary tourniquet to better identify important structures such as nerves and vessels.

Blind ligation or clamping of bleeding vessels could lead to greater damage because the bleeding may be near a neurovascular bundle containing ischemia-sensitive nerves. Careless clamping can also lead to vessel thrombosis, which requires shortening of a vessel and/or interposition of a vessel graft.

Do not allow the patient to smoke prior to making the decision to replant or repair the amputation; smoking can cause vasospasm and complicate the procedure.

For partial amputations, splint the involved extremity to prevent further damage. Reduce any malrotation to limit ischemia. Avoid tension on the tissue bridge, which can damage nerves or vessels. Cooling of a partially amputated part is controversial. If no demonstrable perfusion of the part exists, cool it as if it were completely amputated. If a pulse or bleeding from the capillary bed is present, avoid cooling.

Bone, tendon, and skin can tolerate approximately 8-12 hours of warm ischemia and as long as 24 hours of cold ischemia. However, muscle necroses after 6 hours of warm ischemia or 12 hours of cold ischemia. In general, amputated digits may tolerate 12 hours of warm ischemia and 24 hours of cold ischemia. Other major amputations tolerate 6 hours of warm ischemia and 12 hours of cold ischemia because of their larger muscle content. Excessive ischemia time reduces muscle function and can result in myoglobinuria on reperfusion, placing renal function at risk. More proximal amputations involving more muscles must, therefore, be treated quickly. [18]

Any amputation involves bone and tendon injury and is therefore a tetanus-prone wound by definition. Therefore, 0.5 mL of tetanus toxoid (adsorbed) must be administered intramuscularly if the last booster was received more than 5 years earlier. If the patient has not had primary immunization as a child or if the immunization status is unclear, administer tetanus toxoid as well as tetanus immune globulin (250 U intramuscularly) in opposite limbs.

A digital or regional nerve block is not recommended before a hand or a plastic surgeon evaluates the patient,  because documentation of nerve function prior to surgery is important. Use systemic analgesics with intravascularly administered narcotics.

Transfer of patient

The prevalence of severe associated injuries is 0.8%. Prior to considering transfer, ensure that the patient has no life-threatening conditions other than the amputation, if applicable. Transfer is indicated in the following cases:

  • Amputations of thumbs and/or multiple digits

  • Amputations in children

  • Amputations of individual digits distal to the superficialis insertion

  • Complete amputations that might benefit from acute microsurgical reconstruction (eg, revascularization, coverage of free flap)

  • Clean amputations at the palm, wrist, or forearm

Use of the Internet to transmit high-resolution images, including photographs and radiographs, of potential cases for replantation and use of a digital camera in the ED to facilitate replantation consultation might prevent unnecessary transfer of patients.

Contraindications to transfer include the following:

  • Significant associated injuries

  • Coexisting medical problems (eg, recent stroke, myocardial infarction) that prohibit surgery

  • Prolonged warm ischemia time (>12 h), especially with limb amputations

Relative contraindications to transfer include the following:

  • Amputation of single digits in adults through or proximal to the proximal interphalangeal joint

  • Multilevel injuries

  • Injuries caused by a severe crush-avulsion mechanism

  • Severe contamination

  • Wide segmental tissue injury

Use of bulky dressings should be avoided during transport because these can conceal bleeding. Bleeding should be controlled before applying the dressing or before cooling the distal extremity without perfusion.

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Surgical Care

Surgeons must be skilled at microvascular reanastomosis and be able to achieve a 90% patency rate in a 1-mm – diameter vessel in laboratory animals. [19]  If the vessels of partial or complete finger amputations are suitable for anastomosis, a successful replantation with excellent functional and esthetic recovery can be achieved.

Repair may be performed with an axillary nerve block with bupivacaine, which provides anesthesia lasting 12-16 hours. However, children must have general anesthesia because they do not tolerate axillary block well.

The surgical sequence for replantation varies slightly with amputations distal and those proximal to the wrist and with the mechanism of injury (clean cut, crush, avulsion). Since injury distal to the wrist is more common, the following surgical sequence is delineated:

  • With tourniquet-induced ischemia and use of a microscope, the stump is debrided of all crushed tissue, foreign bodies are removed, and the vessels and nerves are identified and tagged. The amputated part then is similarly debrided, with irrigation of the cut end, while maintaining cooling. Vessels and nerves are identified and tagged. [20]

  • Bones are fixed with K wires, intramedullary screws or pegs, or small plates with screws.

  • The extensor tendon is repaired by using horizontal mattress 4-0 polyester sutures. A tendon graft may also be necessary if a sufficient length of tendon is not available. Finally, if extension is deemed expendable, arthrodesis (joint fusion) may be performed. Then, the flexor tendon is repaired with sutures.

  • Arterial repair is performed next. Brisk blood flow from the proximal vessel should be confirmed prior to vascular anastomosis. Restoration of proximal blood flow may require relief of vascular compression, warming of the patient, administration of adequate blood volume, elevation of the patient's blood pressure, irrigation of the proximal part with warmed lactated Ringer solution, intraluminal flushing with papaverine solution, and correction of systemic metabolic acidosis.

  • Even with a technically successful arterial/venous anastomosis, hemodynamic compromise or insufficient anticoagulation may lead to digital ischemia. As soon as the diagnosis of "no reflow phenomenon" is confirmed, an intra-arterial catheter should be considered followed by an antithrombotic protocol. [21]

  • To avoid thrombosis, reconnect only normal intima visualized under the microscope. A vein graft may be necessary. [20, 22]

  • Tourniquet-induced ischemia may be continued until the anastomosis is complete, although bolus injection of heparin is recommended to prevent thrombosis.

  • Ideally, two veins should be repaired for each artery. No tension should be present on the vessels. If no suitable vein can be found, artery-only replantation can be attempted.

  • Due to the damage associated with avulsion injuries, various vein grafts, vessel transfers from adjacent digits, and venous flow-through flaps have all been demonstrated to increase survival of avulsed fingers.

  • Perform nerve repair next, with fascicular or bundle repair. A nerve graft may be necessary.

  • Skin coverage with grafts or flaps is the final step.

See the images below.

After 2-digit replantation. After 2-digit replantation.
Surgical amputation of a left big toe. Surgical amputation of a left big toe.
Toe-to-thumb transfer. Toe-to-thumb transfer.

Postoperative anticoagulation with heparin, aspirin, and occasionally dextrans is commonly used to prevent thrombosis. A survey of surgeons in the United Kingdom showed that the use of dextran is not uniform and not necessarily beneficial for outcome. [23]  Because of their adverse effects profile, dextrans are less commonly used than aspirin.

Venous insufficiency is reported as the most common complication encountered after replantation, often occurring by postoperative day 3, with an incidence of 7 – 32%. In addition to aspirin, heparin and low molecular weight heparins to prevent thrombosis, pinpricking, milking and medical leeches can be used to induce external bleeding until venous outflow is reestablished. Heparin pledgets placed on a nail bed incision have also been described. [12, 24, 25, 26]

For artery-only replants, injected fluorescein dyes and quantitative fluorometers are used to observe vessel integrity in the digit and monitor for development of a venous outflow tract.

Patients are encouraged to avoid smoking and caffeine for a month because these may enhance vasoconstriction.

Viability of the replanted limb is no longer the sole determinant of success; functional recovery, preoperative and postoperative risks, and duration of treatment are vital factors in making the decision to perform replantation.

The duration of treatment, including rehabilitation, should not exceed 2 years; if it does, the replantation is not thought worthwhile. Amputation with early fitting of prosthesis is a viable alternative in these cases.

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Complications

Detection of perfusion disturbances in digit replantation can be achieved by using near-infrared spectroscopy and serial quantitative fluoroscopy. Near-infrared spectroscopy measurement of tissue oxygenation correlates with fluorescein monitoring and digit perfusion. This noninvasive monitoring is easy, reliable, safe, and useful in postoperative monitoring of digit replantation. [27]

Venous insufficiency is a common complication of digital replantation. Lin et al have reported successful use of a subdermal pocket procedure, used either at the time of replantation if no suitable vein is available after digital artery anastomosis or as a salvage procedure to restore venous drainage. [28]

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Consultations

Consult a microvascular hand surgeon.

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Long-Term Monitoring

Postoperative anticoagulation with aspirin and dextrans is recommended to prevent thrombosis. Patients are encouraged to avoid smoking and caffeine for a month because these may enhance vasoconstriction.

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