Replantation in Emergency Medicine

 

Practice Essentials

Replantation aims to restore the amputated part to its anatomical site, preserving function and appearance. Outcome depends on factors intrinsic to the patient and to the nature of the injury. Young patients who have distal, cleanly amputated extremities have the best return of function; multiple levels of injury, crush, or avulsing injuries have less. Patients must be fully informed about the commitment to rehabilitation and the possibility of multiple surgeries for best results.

As replantation techniques advance, and success rates increase regardless of adverse factors, the focus is shifting from merely achieving anatomic survival through adequate tissue perfusion, to reconstruction of a functional limb. In some instances, a hand with a well-formed stump may be more functional than one with a functionless digit. The goal of replantation should not be the indiscriminate replantation of all severed fingers but the preservation of quality of life through regained function and appearance. This being said, most experts believe thumbs should be reattached regardless of mechanism of injury due to their representation of almost half of hand function.

For additional information, see Hand Amputations and ReplantationDigital Amputations, and Thumb Reconstruction.

Background

In the past 200 years, successful replantation of amputated digits has gradually moved from fantasy to reality. William Balfour performed the first successful fingertip reattachment in 1814; Thomas Hunter is credited with the first thumb replantation performed in the following year.

Little progress was made until the pioneering work of William Steward Halstead and Alexis Carrel, who performed replantation experiments with dog limbs in the 1880s. Dr Carrel won the Nobel Prize in 1912 for his work on vascular anastomoses and for pioneering renal transplantation.

In 1962, Ronald A. Malt performed the first successful replantation of an entire limb in a 12-year-old boy whose arm had been severed in a train accident. With the development of the operating microscope by Julius Jacobson and Ernesto Suarez in the early 1960s, replantation became easier, and its use began to spread throughout the Western world.

With the advent of microvascular reanastomosis, digit replantation became tenable. In 1965, Shigeo Kmatsu and Susumu Tamai were the first to perform such a procedure. Since then, medicine has advanced to include the successful replantation of a child’s completely amputated ear as well as replantation of multiple digits and hands. [12]

Modern replantation is now available in most large hospitals and favorable functionality and cosmetic appearance is increasingly common. [3]

Pathophysiology

Amputation replantation is the reattachment of a completely severed part. This is distinguished from incomplete nonviable amputations, which require revascularization. Revascularization is the reconstruction of the blood supply of an incompletely amputated part. In general, revascularization usually provides better functional results than replantation itself.

However, viability alone is an inadequate measure of success. The main predictive factors include the following [4]

  • Injury mechanism (crushing and avulsion have the worst prognosis)
  • Platelet count
  • Smoking after the operation
  • Preservation method of the amputated part
  • Use of vein grafting

Amputations of the distal phalanx and the thumb, male gender, and ischemia time greater than 12 hours along with presence of diabetes seem to portend a somewhat worse prognosis. Age and history of alcohol use are less significant factors toward the success of replantation. [5]

Etiology

The 6 mechanisms of amputation injury are the following:

  • Sharp cut, as from a knife or meat slicer

  • Dull cut, as from a saw or dull edge (eg, fan blade)

  • Cut with a narrow segment of crush injury, as from a punch press

  • Cut and avulsion, as from a machine that causes partial amputation and subsequent reflexive withdrawal of the hand that completes the amputation

  • Avulsion, as from a finger or a hand caught in an anchor rope or horse reins

  • Crush avulsion, as from a machine (eg, rollers) that crushes the limb then pulls the digits off

Epidemiology

In the United States, 9,407 patients were treated for upper extremity amputation in a 3-year period spanning the first decade of the new millennium, 1,361 of whom underwent replantation (14.5%). [6 Although finger amputation injuries have increased over time, the rate of replantation has declined. In 2001, 2004, and 2007 combined, only 27% of thumb and 12% of finger traumatic amputations were replanted. [7 

Mean age of patients undergoing replantation was 36 years (range, 0-86 y), compared with 44 years (range, 0-104 y) in patients not undergoing replantation. In the United States, 87% of patients with amputation who underwent replantation were male. [6]

African-American patients are less likely to undergo a replantation procedure after experiencing a finger/thumb amputation injury, likely due to disparities in surgical settings associated with system-level differences in access to care. [7 Longer emergency department wait times are associated with lower odds of replantation and being a minority and having no insurance are associated with longer ED wait times. [8 

Hospital charges and length of inpatient stay were significantly higher ($43,000, 5.8 days) for patients with replantations versus those without replantations ($28,000, 3.5 days). Patients treated at teaching facilities were more likely to undergo replantation than those at a nonteaching facility (19% vs 7%). Large hospitals and urban hospitals were more likely to perform replantation. Self-pay, Medicare, and Medicaid patients all had lower replantation rates than patients with private insurance or workers’ compensation. [6 

 

 

Prognosis

Despite recent microsurgical advancements, evidence suggests that in contrast to other developed countries, replantation success rates in the United States have fallen to approximately 60%. [7  This may be due to a significant decline in digital replantations being performed, despite a relatively stable incidence of amputations. Compared with 930 replantations in 2001, only 445 were performed in 2011, more than a 50 percent decrease (p < 0.001). In all years, the majority of hospitals performing replantation performed only one (49.3 to 64.1 percent) each year, with a small minority (2.2 to 8.1 percent) performing more than 10 per year. [9  

The results of a retrospecitive study of 631 digit replantation attempts from five U.S. states found the hospital annual replantation volume increased the odds of success (OR=1.06, CI: 1.02–1.10). An annual hospital volume of 3 replants was needed to achieve a success rate of 70%. [10 

Replantation survival rates of 80-90% have been described in selected reports, but outcome is related not only to the success of the microvascular anastomosis, but to the adequacy of bone, tendon, and nerve repairs. Sensory recovery following digit replantation occurred in 70% of patients, as defined by 2-point discrimination of less than 15 mm. Sensory recovery is better following replantation with sharp-cut mechanism rather than avulsion. Overall, 61% of thumbs and 54% of fingers recovered useful sensory function by 2-point discrimination. [6]

Arterial insufficiency is one of the most common causes for replantation failure. Other causes include venous congestion and thrombosis. 

Function may be limited after replantation. Multivariate analysis of factors that favor functional recovery after finger replantation or revascularization showed better recovery for patients younger than 40 years compared with older patients. Injuries caused by a sharp mechanism have a better prognosis than those caused by a crush mechanism; injuries caused by a crush mechanism have a better prognosis than those caused by avulsion; and injuries at the middle phalangeal level have a better prognosis than those at the proximal level. A meta-analysis showed that smoking, diabetes, and avulsion or crush injury are poor prognostic factors in replantation of amputated digits.  [5]

Cold intolerance of the replanted limb is a universal problem. [11Similarly, cold-induced vasospasm occurs in essentially all patients. Sensitivity to light touch and 2-point discrimination frequently is impaired, while limitations in the flexion of joints distal to the replantation vary. Cosmetic deformity may occur.  Average finger flexion for reimplanted digits has been shown to be 129°. Replantation in zones 1 and 5 fared better than those in zones 2 through 4. As with survival and nerve function, avulsion mechanisms had poorer outcomes. [6]

Complications following reimplantation include infection and osteomyelitis. Myonecrosis leading to rhabdomyolysis and renal insufficiency may occur if significant muscle mass that was transiently ischemic is replanted. These occur with forearm or lower leg replantations but not with finger replantations. 

Replantation in Emergency Medicine Clinical Presentation


History

An adequate history of the amputation injury is important and should include the following:

  • Mechanism, time, and place of injury
  • Condition of the injured part
  • Patient's hand dominance
  • Patient's general condition

Type of injury is the most important factor in determining the likelihood of survival and functionality of the replanted part. Injuries due to sharp mechanisms have a much better chance of successful replantation than those caused by blunt crushing forces. If a narrow zone of crush injury is present, replantation may be possible by excising the crush zone and replanting with clean margins.

Avulsion amputations caused by rollers offer a markedly reduced chance of successful, functional replantation, although such repairs are not impossible. Degloving injuries are those in which the soft tissue is torn from the underlying bone, as when a glove is removed from the hand. These often are a result of jewelry getting caught in machinery.

The time elapsed since injury affects the amount of local and systemic hemorrhage and, hence, the degree of ischemia in the tissue and amputated part. In addition, wound contamination progresses with time because bacteria proliferate on the wound surface. The source of contamination may influence the choice of antibiotic, method and duration of irrigation, and degree of debridement prior to replantation.

Determine the patient's dominant hand, although this information is of only relative importance.

Ask about allergies, immunizations, and chronic active disease processes.

Ask if any old injury is present. Negative prognostic factors include old age, peripheral vascular disease, congestive heart failure, and diabetes mellitus with complications. In the surgeon's judgment, these factors may make replantation inadvisable.

Assess the patient's psychiatric history. If the amputation was self-inflicted, a psychiatric evaluation is recommended.

Physical Examination

Perform a detailed examination of the hand, which includes distinction in function between flexor digitorum profundus and flexor digitorum superficialis. Also, describe the injury and neurovascular status. Check sensation on both sides of the distal part to assess digital nerve function before any digital nerve anesthesia.

In cases of amputated digits, determine whether the amputation is within zone II of the hand (proximal to the flexor digitorum superficialis tendon insertion). Injuries in this zone are associated with poor postoperative functional outcome due to development of a stiff proximal interphalangeal joint that negatively impacts overall hand function. [12]

A red-line sign may be seen in avulsion injuries with associated traction on the neurovascular bundle. These are small subcutaneous hematomas caused by intimal tears along the bundle. This is usually a negative prognostic sign.

A ribbon sign is seen in patients where the blood vessel was subjected to stretch and torsion. The vessel will resemble a gift-wrap ribbon. This also portends a negative prognosis.

Complete amputation of 2 digits. Complete amputation of 2 digits.
Complete thumb amputation. Complete thumb amputation.
Complete thumb amputation. Complete thumb amputation.
Surgical amputation of a left big toe. Surgical amputation of a left big toe.

Perform a general physical examination, concentrating on cardiovascular disease.

Perform a rectal examination to ensure that anticoagulation can be accomplished during or after surgery, if necessary, without placing the patient at risk for gastrointestinal bleeding.


Replantation in Emergency Medicine Workup


Laboratory Studies

Assess the patient's hemoglobin/hematocrit at baseline, and follow up with serial determinations if significant blood loss is suspected. Assess coagulopathy by determining the prothrombin time/international normalized ratio (INR) and platelet count if the patient's history suggests a bleeding disorder or liver disease.

Type and cross-match 2-4 units of packed red blood cells if the patient's history suggests significant blood loss.

Obtain an electrocardiogram in patients older than 45 years and in those with a history of cardiac ischemia or arrhythmia.

Pulse oximetry can be used to document arterial flow to a part that is incompletely amputated when clinical findings of arterial flow with Doppler ultrasonography suggest an absence of arterial perfusion. [1314]

Imaging Studies

Radiographs of the injured part should be performed as follows:

  • Obtain posteroanterior, lateral, and oblique radiographs of the amputated part and stump.

  • Carefully assess for radiopaque foreign bodies.

  • Comminution of the fracture implies a crush injury mechanism and is associated with soft-tissue trauma.

  • If the joint is destroyed at the level of amputation, perform arthrodesis (fusion); this results in loss of joint function.

  • If a crush injury is severe, a mosaic of fragments may preclude attempts at replantation.

See the images below.

Radiologic appearance of a hand with 2-digit amputRadiologic appearance of a hand with 2-digit amputation.
Radiologic appearance of a complete thumb amputatiRadiologic appearance of a complete thumb amputation.

Obtain a chest radiograph if it is indicated by the patient's age or underlying lung or heart disease or if blunt or penetrating chest injury is suspected.


Replantation in Emergency Medicine Treatment & Management



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. [1617]

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.

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. [2022]

  • 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. [12242526]

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.

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]

Consultations

Consult a microvascular hand surgeon.

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.


Replantation in Emergency Medicine Medication


Medication Summary

Prophylactic antibiotics are indicated with amputation, crush, or degloving injuries. Devitalized tissue is a good culture medium for bacterial contaminants. Common pathogens are Staphylococcus aureus (the most likely organism) and group A streptococci, whereas Clostridium species and organisms from the Enterobacteriaceae family are less common. Gram-negative and anaerobic bacteria are more commonly found with extensive tissue damage or with wounds grossly contaminated with soil, saliva, or feces. In these cases, perform Gram staining and cultures before initiating antibiotic therapy.

If the amputation is from a human bite, antibiotic coverage should include streptococci, Eikenella corrodens, anaerobic bacteria, and staphylococci. Use oral amoxicillin and clavulanate for human bites without amputation. Use intravenous ampicillin and sulbactam or ticarcillin and clavulanate for amputations or established infections caused by human bites. A combination of penicillin G and an antistaphylococcal antibiotic is also acceptable for minor bite wounds.

Antibiotics

Class Summary

Empiric antimicrobial therapy must be comprehensive and should cover all likely pathogens.

Cefazolin (Ancef, Kefzol)

First-generation semisynthetic cephalosporin; binds one or more penicillin-binding proteins; arrests bacterial cell-wall synthesis and inhibits bacterial growth; primarily active against skin flora, including S aureus.

Ampicillin and sulbactam (Unasyn)

Drug combination that involves a beta-lactamase inhibitor with ampicillin; covers skin organisms, enteric flora, and anaerobes; not ideal for nosocomial pathogens.

Ticarcillin and clavulanic acid (Timentin)

Inhibits biosynthesis of cell wall mucopeptide and is effective during stage of active growth; antipseudomonal penicillin and a beta-lactamase inhibitor covers most gram-positive and gram-negative organisms, as well as anaerobes.

Analgesics

Class Summary

Pain control is essential to quality patient care, ensuring patient comfort and promoting pulmonary toilet. Most analgesics have sedating properties, which are beneficial for patients with painful skin lesions.

Fentanyl (Duragesic)

More potent narcotic analgesic with a much shorter half-life than morphine sulfate; drug of choice for conscious sedation analgesia; ideal for analgesic action of short duration during anesthesia and in immediate postoperative period. For patient needing long-term pain control, sustained-release fentanyl transdermal patch (Duragesic) may control pain with 72-h dosing intervals; some patients require dosing intervals of 48 h. Onset of transdermal fentanyl patch analgesia is delayed for 8-12 hours, so acute pain control must be provided prior to full effect of patch. Overdose has been reported, so start with lowest dose/hour patch (25 mcg/h).

Morphine (Astramorph, MS Contin, Duramorph, Oramorph)

Drug of choice for narcotic analgesia because of its reliable and predictable effects, safety profile, and ease of reversibility with naloxone. Various IV doses are used and are commonly titrated until desired effect is obtained.

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