Extremity replantation: Indications and timing

History

In 1958, Onji and Tamai attempted the first revascularization of an incompletely amputated thigh on a 12-year-old girl in Japan; the replant eventually failed due to overwhelming infection and thrombosis. A year later, they were successful in restoring the nerve supply in another patient with an incomplete amputation at the level of the thigh. Laboratory studies and early clinical experiences limited replantation to hands and digits at that time. Ronald Malt performed the first extremity replantation on May 23, 1962, on a 12-year-old boy who amputated his arm at the level of the neck of the humerus in a train accident. Malt later reported that the patient had some functional recovery of the arm after wrist arthrodesis and tendon transfers. In 1963, Chen et al reported the first successful replantation of a hand in Shanghai, China, after a young factory worker had his hand reattached at the wrist. With the successful recovery of hand function, this became the first published replantation case. In 1964 Kleinert and Kasdan reported a successful revascularization of an incompletely amputated thumb. The next year, Tamai et al successfully performed the first thumb replantation after a clean amputation at the metacarpophalangeal joint.

The successes of these procedures led to continued research and development in the field of reconstructive microsurgery. During the 1960s, Harry Buncke earned the name of the “founding father of microsurgery.” In 1965 he published his work on replantation of a thumb on a rhesus monkey, followed by a hallux-to-hand transplantation on a rhesus monkey in 1966. Buncke later published his work on rabbit ear replantation, demonstrating the necessary instrumentation and techniques necessary for microvascular anastomosis. Refinements in techniques, instrumentation, and standardization of indications have been made, thus allowing the field of digital and extremity replantation to expand.

Microsurgical centers

Surgeons specializing in hand surgery are often trained to perform revascularizations, replantations, and other microsurgical procedures. The best postoperative outcomes are seen at centers that routinely perform complex reconstructive microsurgery. A team effort between surgeons, anesthesiologists, and nursing staff is required for a successful outcome. Replantations are best served in a center specializing in microsurgery with the following elements available:

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  An experienced microsurgical team able to work in shifts

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  An efficient network of ground and air transportation systems to transfer patients from the referring hospital to the microsurgical center

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  Organized anesthesiologists and an operating room and perioperative nursing staff available 24 hours a day, 7 days a week

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  Proper microscopes, instruments, and sutures

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  Trained postoperative nursing staff and access to an intensive care or similar specialty unit for diligent postoperative care and monitoring

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  Hand therapists trained in postreplantation hand therapy

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  Psychological and social service support to help the patient adjust to his or her injuries

Transportation

Prior to transportation, the referring physician should stabilize the patient and confirm that no coexisting life-threatening injuries exist. The physician must then prepare the amputated part and patient for transport to the replantation center. Early contact with the microsurgeon by the referring physician with specific information increases the chance of a successful outcome.

Several questions must be answered prior to transportation:

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  What time did the injury occur, and at what point was the part cooled (“cold ischemia time”)?

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  What was the mechanism of the amputation? Was it a crush, avulsion, degloving, or guillotine injury?

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  What is the level of the injury/amputation?

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  Is the amputation complete or incomplete? If not complete, are there any signs of circulation or sensation?

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  Which hand or limb is injured, and were there any previous injuries to that part?

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  Does the patient have any other injuries?

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  Does the patient have any other comorbidities, particularly those that would hamper wound healing after replantation?

Answering these questions can effectively help triage and facilitate moving the patient to the appropriate center for definitive care.

If available, radiographs and pictures of the affected hand or limb may be requested by email or short messaging service (text messaging) for evaluation by a microsurgeon. Buntic et al state that when possible they like to talk to emergency room patients at the referring hospital over the telephone. This allows the patient to be better informed about the probability of replantation and the risks, benefits, and alternatives. Pictures of the affected part(s) and radiograph images allow this discussion to be more individualized.

Once it has been determined that the patient is hemodynamically stable and been accepted to a microsurgical center, arrangements can be made to transfer the patient and the amputated part. The stump should be covered with a saline-moistened gauze pad and loosely wrapped and splinted if possible for comfort. A digital block should never be performed prior to arrival at the microsurgery center, as there is a high potential of inadvertently disrupting the anatomy and possible inflow to the amputated portion. The amputated part is placed in a lightly moistened gauze pad, then placed in a watertight bag and placed on ice ( Fig. 1 ). Care should be taken not to let the amputated part come in direct contact with the ice as this may cause inadvertent thermal injury (frostbite). Using this technique, digits have been replanted up to 48 hours after amputation and parts with muscles up to 12 hours after amputation.

Evaluation of the amputated part

Once the patient arrives to the microsurgery center, the amputated part(s) should be evaluated. It may be unrealistic to successfully replant a severely crushed and mangled body part. Avulsion injuries with traction along the neurovascular bundles create intimal tears and disruption of small branches to the skin. Small hematomas seen in the skin along the course of the neurovascular bundle result in the “red line sign.” This sign signifies significant injury to the neurovascular bundle so much so that replantation is often fraught with complications or is unsuccessful. Replantation of digits with the red line sign require vein grafting across this zone of injury to be successful.

The “ribbon sign” is another finding on an amputated part that signifies vessel damage. The ribbon sign is an indication of torsion and stretch on a vessel. The vessel resembles a ribbon that has been stretched and curled for decoration on a birthday present. Vessels that have the ribbon sign often are not amenable to sustaining blood flow, precluding replantation attempts ( Fig. 2 ).

Indications

Motivation and intelligence of the patient are two major factors influencing the functional outcome after replantation and revascularization. In general, a patient with a partial or complete amputation of the hand is a candidate for replantation. Optimal candidates will have sustained sharp, guillotine-type injuries to the thumb, multiple digits, hand, or wrist with minimal contamination. When deciding whether to replant the digit, the surgeon should consider function of the hand as a whole of the patient after a replant versus merely closing the amputated stump and fitting the patient with a prosthesis.

Every effort must be made in replanting a digit in a child. Replantation in a child is technically more challenging due to the small caliber of the vessels and vasospasm and may require the application of supermicrosurgical techniques. Nevertheless, the digit does grow with the child and the results of tendon and nerve repair are superior to those in an adult.

Contraindications

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  Significant associated injuries: Digital amputations are rarely associated with other major injuries, but major amputations of the arm are frequently associated with head, chest, and abdominal injuries. These injuries may be life-threatening and may preclude replantation of the upper extremity or amputation.

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  Multiple injuries within the amputated part: Extensive damage along the digital arteries from a crush or avulsion mechanism may preclude replantation. Extensive crushing or degloving of the amputated part or segmental amputations at multiple levels in the digit or hand are usually a contraindication to replantation. Clinical inspection of the amputated part may be correlated with radiographs that may reveal fractures at multiple levels.

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  Systemic illness: Elderly patients with a previous history of a myocardial infarction, heart failure, chronic obstructive pulmonary disease, or insulin-dependent diabetes may not be candidates for prolonged surgery and anesthesia. A general rule is that patients who cannot tolerate general anesthesia are likely not candidates for replantation.

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  Age: Elderly patients may have significant systemic disease, but more importantly, the recovery of tendon and nerve function in the replanted digit is usually poorer compared with a younger patient. There also is an added risk of producing stiffness in the joints of adjacent uninjured fingers. Arteriosclerosis is relatively rare in the arteries of the upper extremity but can occasionally complicate the anastomoses of the radial and ulnar arteries during replantation at the wrist level in an elderly patient.

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  Avulsion injuries: With avulsion injuries, there is usually extensive damage to the digital arteries and digital nerves both proximal and distal to the level of amputation. Avulsion amputations of the digits resulting from rodeo or water-skiing injuries are fairly obvious on clinical inspection, with long segments of the digital nerves or flexor and extensor tendons attached to the amputated digit. In contrast, the digital arteries are usually avulsed distally from within the digit, sometimes all the way to the trifurcation of the digital artery at the level of the distal interphalangeal (DIP) joint. Replantation will only be successful if a normal-appearing lumen of the distal digital artery can be found before the digital artery trifurcates and usually requires the use of interposition vein grafts.

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  Prolonged warm ischemia time: Muscle is the tissue most susceptible to ischemia and begins to undergo irreversible changes after 6 hours at room temperature. Because a proximal forearm or upper arm amputation contains a significant muscle mass, it is vitally important that such amputations be cooled as quickly as possible and if necessary, reperfused through arterial shunts to reduce the warm and cold ischemia times and allow successful replantation. Because digits do not contain muscles, they have a longer ischemic tolerance. With multiple digital amputations, Chiu et al reported a successful replantation after 33 hours of warm ischemia, and Wei et al reported a successful replantation after 94 hours of cold ischemia.

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  Massive contamination: Radical surgical débridement precedes any major upper extremity replantation, but occasionally, massive contamination in farm injuries or by impregnation of all tissues by oil or grease in industrial injuries may prevent radical débridement and therefore preclude replantation because of the risk of infection and overwhelming sepsis.

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  Psychological problems: Self-inflicted amputations, usually of the hand or wrist, may precede a later successful suicide attempt. These patients require an emergency psychiatric consultation prior to any replantation.

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  Single-digit amputations: Although a single-digit amputation should always be replanted in children, replantation of a single digit in an adult remains controversial. Viability can be restored after amputation proximal to the proximal interphalangeal (PIP) joint; digital motion is compromised because of the adhesions associated with flexor tendon repairs in zone II, resulting in less than satisfactory flexion at the PIP and DIP joints. Replantation of an index finger amputation proximal to the PIP joint in an adult is usually unsatisfactory, because the brain excludes the index finger and substitutes the middle finger for thumb-middle finger pinch. Similarly, replantation of a single middle finger, ring finger, or small finger may interfere with the motion of the other two fingers as a result of the common origin of the flexor digitorum profundus (FDP) tendons. However, replantation of a single-digit amputation through the middle phalanx distal to the insertion of the flexor digitorum sublimis (FDS) tendon or through the distal phalanx may provide excellent sensory return, maintaining full flexion at the PIP joint.