Revascularization and Replantation of the Digits
DEFINITION
Replantation is the reattachment of a completely amputated body part.
Revascularization is the restoration of circulation and repair of all injured structures in an incompletely amputated, dysvascular body part. Revascularization always includes repair of blood vessels to reestablish blood flow to the part.
Revision amputation is the procedure performed at the site of amputation to gain soft tissue coverage and to address concomitant injuries to the digit.
The decision of whether to perform replantation or revascularization and revision amputation of a digit is multifactorial. The relative indications and contraindications for each are discussed later in the chapter.
ANATOMY
An understanding of the anatomy over the complete length of the digit is essential for successful replantation. The anatomy of the thumb is different from that of the four fingers.
Palmar and dorsal cutaneous ligaments maintain the position of the neurovascular bundle during range of motion of the digit.
Grayson ligament is palmar to the neurovascular bundle, originates from the flexor tendon sheath, and inserts on the skin.
Cleland ligament travels dorsal to the neurovascular bundle from the phalanx to the overlying skin.
A radial and ulnar proper digital artery supplies each digit. Each vessel travels with a respective radial and ulnar proper digital nerve. At the level of the digit, the artery lies dorsal to the nerve.
The ulnar digital artery is typically larger in the thumb and index fingers. The radial digital artery usually is larger in the small finger.
Three major palmar arches arise from the digital arteries. The proximal, middle, and distal arches are consistently located at the level of the C1 pulley, C3 pulley, and just distal to the flexor digitorum profundus (FDP) insertion, respectively.
Four palmar and four dorsal branches usually extend from each digital artery.
Injection studies have demonstrated that the venous system of the digit consists of a series of arcades on the
dorsal and palmar surfaces, with connecting oblique and transverse anastomotic veins.10 The dorsal veins have a larger caliber than the palmar veins, which do not consistently travel with the digital artery and nerve.
A radial and ulnar proper digital nerve travels with each proper digital artery. The digital nerve is sensory only and typically contains one to three fascicles. It trifurcates at the level of the distal interphalangeal (DIP) joint.
Each finger has two flexor tendons within the flexor tendon sheath. The FDP tendon inserts at the proximal base of the distal phalanx.
The flexor digitorum superficialis (FDS) tendon inserts as two slips into the midportion of the middle phalanx.
The FDS tendon splits into two slips, and its relative position to the FDP tendon switches from palmar to dorsal at Camper chiasm. This allows the deeper FDP tendon to continue to its more distal insertion.
There are a series of five annular and three cruciform pulleys, which are discrete thickenings of the fibro-osseous sheath. The annular pulleys prevent bowstringing of the flexor tendons during flexion, whereas the cruciate pulleys are collapsible, accommodating flexion.
The odd-numbered annular pulleys are located over the joints of the finger, and the even-numbered annular pulleys are over the proximal and middle phalanx, respectively.
The A2 and A4 pulleys are most important in preventing bowstringing and should be preserved if possible.
Each lesser digit receives a tendon from the extensor digitorum communis (EDC). The index and small fingers each have a second extensor tendon, the extensor indicis proprius (EIP) and extensor digiti minimi (EDM), respectively. Both of these tendons are ulnar to the EDC tendons.
PATHOGENESIS
The mechanism of injury has a considerable effect on the potential for replantation. Sharp amputations are ideal for replantation because of the narrow zone of injury.
The degree of tissue injury increases substantially with crush and avulsion mechanisms and may prohibit successful replantation (FIG 1).
Most digit amputations occur as an isolated injury. When amputations occur in the multiply injured patient, consideration of other systemic injuries and adherence to advanced trauma life support (ATLS) protocols may prevent replantation.
NATURAL HISTORY
Replantation of an amputated digit results in longer hospital stays and more prolonged rehabilitation than revision amputation. Patient satisfaction, however, usually is higher with replantation than with revision amputation or a
prosthesis.8,11,12
Functionally, the expected range of motion in a replanted digit is 50% of normal. Secondary procedures, such as tenolysis, are common.
The literature reports rates of reoperation ranging from 3% to 93%. In a series of more than 1000 replants and
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revascularizations, 35% of patients required at least one secondary surgery.18 The incidence is higher for replantations than for revascularizations.
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FIG 1 • A. This hand sustained sharp amputation of the digits from a table saw. The narrow zone of injury made the digits ideal for replantation. B. This hand sustained a crush injury. The resultant wide zone of injury prohibited successful replantation.
Expected survival rates of replanted digits are 80% or higher, with even higher survival rates in revascularized digits.
PATIENT HISTORY AND PHYSICAL FINDINGS
The surgeon must evaluate the patient in the emergency room immediately on arrival. A complete history and physical examination are performed.
The history should include specific details regarding the mechanism and timing of the injury. Identification of the specific machinery involved often reveals valuable information about potential contamination and the pattern of injury sustained by the amputated part.
A history of mental instability is relevant because rehabilitation protocols require significant patient compliance to maximize functional outcomes. Furthermore, self-inflicted amputations are unlikely to yield the same functional results after replantation as accidental amputations.
A history of medical comorbidities should be thoroughly evaluated. Conditions such as diabetes, peripheral vascular disease, hypercoaguability, and tobacco use are not absolute contraindications to replantation but must be considered.
Similarly, the surgeon must evaluate for medical conditions that prevent the patient from tolerating the blood volume changes associated with major limb replantation. Revision amputation may be the best choice if the patient has a history of previous trauma or arthritis in the amputated part.
Ischemia time and method of transport should be evaluated for appropriateness. In the digits, a warm ischemia time of less than 6 hours is desired. In more proximal amputations containing muscle, ischemia time is more critical.
Cooling the amputated part reduces metabolic acidosis, bacterial growth, and muscle necrosis. Cold ischemia times of up to 12 hours are tolerated for replantation of digits. There are reports of successful replantation of
digits with warm ischemia times of 42 hours and cold ischemia times of 96 hours.2,19
Proper transportation of the amputated part is essential. Never place the part directly on ice. The part should be wrapped in a sterile gauze moistened with Ringer lactate or normal saline. The gauze is then placed in a leakproof plastic bag and the bag is placed on ice (FIG 2). The temperature should be maintained at approximately 4° C.
Alternatively, the part may be immersed in Ringer lactate or normal saline in a plastic bag with the bag then placed on ice.
The surgeon examines the part and the injured extremity to evaluate suitability for replantation. The number of digits, level of injury, and type of injury are assessed.
Specifically, the surgeon evaluates the injured parts for the red line sign and the ribbon sign.
The red line sign refers to a red streak of ecchymosis along the lateral border of the digit, which is the result of hemorrhage from avulsed branches of the digital artery after a traction injury (FIG 3).
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FIG 2 • The amputated part should be wrapped in a sterile gauze moistened with Ringer lactate or normal saline. The gauze is then placed in a leakproof plastic bag, which is placed on ice. The part should never be placed directly on ice.
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FIG 3 • The red line sign, which represents an avulsion injury, is seen clinically as a red streak of ecchymosis along the lateral border of the digit. This ecchymosis is the result of hemorrhage from avulsed branches of the digital artery after a traction injury. The ribbon sign, which also represents an avulsion injury, refers to the
corkscrew appearance of the digital artery resulting from disruption of the vessel wall layers. When these clinical signs are present, the zone of injury must be bypassed with vein grafts if replantation is attempted.
The ribbon sign also represents an avulsion injury (see FIG 3). Coiling of the artery at the amputation site
results from disruption of the vessel wall layers from traction.17 If replantation is attempted, vein grafting is often required.
IMAGING AND OTHER DIAGNOSTIC STUDIES
When the patient arrives in the emergency department, standard radiographs of the amputated parts and the injured limb are obtained (FIG 4).
Laboratory evaluations should include a complete blood count, basic metabolic panel, coagulation panel, drug screen, and blood type and crossmatch. Other preoperative tests are ordered as indicated by the patient's age and comorbidities.
NONOPERATIVE MANAGEMENT
There is no role for nonoperative management of these injuries.
Some surgeons advocate performing revision amputations in the emergency department under local anesthesia. It has been our experience that these procedures are best performed in the operating room with appropriate anesthesia, hemostasis, sterile conditions, lighting, and equipment.
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FIG 4 • A. Standard posteroanterior (PA) radiograph of the injured hand. B. A radiograph of the amputated parts is also obtained by placing the bag containing the parts directly on the x-ray cassette.
SURGICAL MANAGEMENT
The decision to replant a digit is predicated on the determination that the anticipated function after replantation will be better than that of a revision amputation. This determination is made after careful consideration of the factors
influencing the predicted survival of the replanted digit, morbidity to the patient, and functional outcome. Specific factors related to the status of the amputated part and the status of the patient include the following:
Mechanism of injury (eg, sharp, crush, avulsion) Level of amputation
Ischemia time (warm or cold) Health of patient
Age of patient
Presence of segmental injury Predicted rehabilitation Vocation and hobbies
Informed consent for replantation versus revision amputation must reference the postoperative care differences.
Patients undergoing revision amputation typically are discharged from the hospital much quicker and have much shorter, less intensive rehabilitation protocols.
Patients treated by replantation typically require a 5- to 7-day hospital course, avoidance of smoking and caffeine, possible blood transfusions, and prolonged rehabilitation. Furthermore, these patients must be advised about the likelihood of cold intolerance.
The techniques we use for replantation of amputated digits are described in detail in the following sections. The same techniques and sequence of repair are followed for the revascularization of partially amputated parts.
In partial amputations, not all structures will be injured, so it may be that only some structures require repair. For example, if the dorsal skin and its veins remain intact, the procedure does not require venous anastomosis for outflow.
Each case should be examined individually, and all structures should be carefully evaluated for injury.
Preoperative Planning
Broad-spectrum antibiotics and tetanus prophylaxis are administered on presentation in the emergency department.
The patient, hand, and amputated parts are examined to confirm suitability for possible replantation. A urethral catheter should be placed for long procedures.
Regional anesthesia is preferred to facilitate autonomic blockade, which results in increased peripheral vasodilation. Ideally, an indwelling catheter is placed to allow for continuous postoperative pain relief and sympathetic block. General anesthesia is required for children.
If an attempt at replantation is determined to be appropriate and desired, the parts are brought to the operating room as soon as possible. Initial preparation of the parts can begin while the anesthesia team evaluates the patient.
The operating room and patient must be kept warm to prevent peripheral vasoconstriction. The sequence of repair is as follows:
Débridement and identification of structures Bone shortening and fixation
Extensor tendon repair
Flexor tendon repair
Arterial repair Nerve repair Vein repair
Skin closure/coverage
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Positioning
The patient is positioned supine on a standard operating room table with a hand table attachment. The table is rotated 90 degrees to allow access for the operating microscope and fluoroscopy.
Approach
Slightly dorsal midaxial incisions are made on both the radial and ulnar sides of the digits. These incisions allow for rapid identification of both the neurovascular bundles and the dorsal veins. Both the palmar and dorsal flaps can be reflected as needed (FIG 5).
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FIG 5 • A,B. Bilateral longitudinal midaxial incisions allow for easy exposure of the neurovascular bundles and dorsal veins.
TECHNIQUES
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Preparation of the Amputated Part
A two-team approach is used. One team prepares the amputated part, whereas the other team prepares the patient.
The parts should continue to be kept cool until they are reattached. A sterile prep table and a sterile covered ice-filled basin are required for preparation of the parts (TECH FIG 1).
A sterile metal irrigation basin is filled with ice and covered with a sterile adhesive drape. A moist sterile towel is placed over the drape as a working surface.
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TECH FIG 1 • A,B. The amputated parts are removed from the bag, and a sterile prep is performed on a separate table. C. A sterile metal irrigation basin is filled with ice and covered with a sterile adhesive drape. Use as much ice as can be placed without disruption of the sterile environment to maximize contact with the amputated parts. D. A sterile surgical towel is then placed over the drape and used as a working surface. E. Nylon sutures placed through the amputated parts are secured to the surgical towel. The amputated parts are now ready for débridement and preparation.
The basin should be filled such that the ice forms a mound above its rim.
The parts are brought to the operating room and cleaned on the sterile prep table with Hibiclens and sterile Ringer lactate.
A nylon suture is passed through the tip of each amputated part and secured to the towel with a small hemostat.
Under loupe magnification, the contaminated skin edges and subcutaneous tissues are débrided.
Slightly dorsal midlateral incisions are made on the radial and ulnar sides of the digit. Arteries, nerves, and veins are identified
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and tagged for later with small hemoclips or microsutures. The hemoclips should be placed as close to the vessel and nerve ends as possible to avoid damaging the structures.
The nerves and vessels are exposed for a length of 1.5 to 2 cm. The veins lie in the subdermal plane and can be identified by elevating the dorsal skin flap. If the veins are difficult to isolate, the surgeon may defer their identification until after the anastomosis of one artery when engorgement makes them more prominent.
The flexor tendons are identified, and a 4-0 nonabsorbable braided suture is placed in each tendon in a Tajima fashion. The crossing limb of the Tajima suture should be placed 1.0 to 1.2 cm from the free end of the tendon.
The bone is then shortened appropriately. Consideration of the level and geometry of amputation is required. It is necessary to reference the recipient site to match the orientation of the bone ends.
In general, 4 to 10 mm of total digit shortening allows for appropriate débridement of nerves and vessels to
healthy tissue and subsequent primary repair without tension. Shortening also eases skin coverage of the repair site. The amount of shortening depends partly on the mechanism of injury. Crush injuries typically require more resection than sharp injuries.
Two 0.045-inch Kirschner wires (K-wires) are placed longitudinally down the long axis of the bone in a retrograde fashion. The K-wires should exit through the tip of the digit just palmar to the nail. The K-wires are advanced until the tips are showing through the bone so that the amputated digit is now ready for immediate attachment.
The parts should continue to be kept cool under ice packs until they are reattached.
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Preparation of the Stump
The second surgical team initiates preparation of the injured extremity while the amputated parts are being prepared.
Under tourniquet ischemia and loupe magnification, débridement of the skin and subcutaneous tissues is performed.
In an identical manner to the amputated parts, the arteries, nerves, and veins are identified, tagged, and exposed through slightly dorsal midlateral incisions. The veins are the most difficult structures to identify on the stump. Once a vein is located, continue the dissection in the same subdermal plane to identify others. If possible, two veins are repaired for each artery.
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TECH FIG 2 • A. A Tajima-type suture repair is used so that the flexor tendons can be opposed and secured at the ideal time. B,C. The suture is placed in the proximal and distal ends of the tendon. D. The sutures are then tied in the repair site at the appropriate time.
Flexor tendons are identified, and a Tajima suture is placed in each (TECH FIG 2). If the tendons have retracted proximally, atraumatic retrieval is necessary to avoid inducing spasm or damaging the proximal
vessels. If required, a separate proximal incision is made to retrieve the tendons safely.
After identifying all structures, evaluate the need for grafts. Every attempt should be made to repair all structures primarily. Delayed reconstructions are much more difficult, place the repaired vessels at risk, and subject the patient to additional surgery and rehabilitation.
Any amputated parts that are not being replanted should not be discarded because these are an excellent source for donor grafts(skin, bone, nerve, vessel).
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Bone Fixation
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Bone shortening has already been performed at the time of débridement. If shortening was limited by the proximity of joints, the use of vein grafts should be entertained at the time of vessel anastomosis. When shortening the bone in a thumb amputation, the resection should be maximized on the amputated part so that if the replant fails, thumb length is maintained.
Numerous methods of bone fixation are available, including longitudinal K-wires, crossed K-wires, intraosseous wiring (so-called 90-90 wiring), tension band wiring, intramedullary screw, and plate and screws.
Parallel longitudinal K-wires are quick, easy, and have low nonunion and complication rates.7 When possible, this is our preferred technique (TECH FIG 3A-D).
Crossed K-wires are also relatively quick and easy to use. The drawback to crossed K-wires is potential risk to the neurovascular bundles, either directly or by tethering (TECH FIG 3E-H).
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TECH FIG 3 • A-D. Parallel longitudinal K-wires allow for easy and rapid fixation with low complication rates. (continued)
Intraosseous wiring takes more time and exposure to perform but allows for early range of motion. Drill holes accepting of a 24-gauge wire are placed in a dorsal to palmar and radial to ulnar orientation at each bone end. Two loops of 24-gauge wire are then passed perpendicular to each other through the analogous drill holes at each bone end and tightened in standard cerclage fashion.
The tension band technique is a useful option for arthrodesis because it allows the surgeon to set the desired amount of flexion. Two parallel 0.045-inch K-wires are placed across the fusion site, and a figure-8 loop of 24-gauge wire is used over the dorsum of the finger to complete the construct.
The intramedullary screw is most useful in thumb amputations at the metacarpal level. Removal of this hardware is difficult, so its use should be avoided in highly contaminated wounds where the risk of infection is high.
Lag screw fixation is appropriate to treat long oblique fractures. However, because most amputations do not result in this fracture pattern, this technique is seldom used in replantation surgery.
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TECH FIG 3 • (continued) E-H. In more proximal amputations, longitudinal K-wires may not be possible. Crossed K-wires can be used successfully in these injuries.
Plate-and-screw fixation is generally not required in digit replantation because nonunion is rare. Although it provides rigid fixation, the hardware is bulky, increases tendon adhesions, and requires more time and exposure.
Regardless of the method of fixation, the surgeon must constantly evaluate alignment and rotation of the digit in both flexion and extension. The flexed fingertips should point toward the distal pole of the scaphoid.
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Extensor Tendon Repair
After bone stabilization, the extensor mechanism is repaired.
In the digit, the tendon is repaired with two horizontal mattress sutures using a 4-0 nonabsorbable suture.
It is imperative to repair the entire extensor mechanism. If the amputation is through the proximal phalanx, repair of the lateral bands will optimize functional outcomes.
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Flexor Tendon Repair
Because the Tajima sutures have already been placed, they are now ready to be tied in the repair site. The two strands of the repair should be tied simultaneously to achieve a symmetric repair.
In certain circumstances, the surgeon may choose to delay tying the sutures until after the microsurgical portion of the case. Specifically, in very proximal amputations, the ability to position the digit in slight hyperextension may facilitate the vessel and nerve repair.
Both the FDS and FDP are repaired when feasible. If the amputation is in zone 2 and the tendons are not cleanly cut, repair of only the FDP tendon is reasonable.
If the amputation level is distal to the FDS insertion, but proximal to the DIP joint, we typically do not repair the FDP or extensor tendon. We favor arthrodesis of the DIP joint with K-wires and direct rehabilitation toward early active and passive range of motion of the proximal interphalangeal (PIP) joint.
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Arterial Repair
We have found that both digital arteries should be repaired, when feasible, to maximize survival rates. The operating microscope and microsurgical instrument set are used.
The most important factor affecting survival is achieving a tension-free anastomosis of normal intima to normal intima (TECH FIG 4A-C).
Débridement of damaged arteries is performed under the operating microscope. The surgeon must resect until normal intima is identified. The liberal use of vein grafts is advocated for resulting defects.
The tourniquet is released to ensure good blood flow from the proximal stumps.
Sharply trim the proximal stump with angled Potts scissors and dilate the lumen with jeweler's forceps or a
lacrimal duct dilator.
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TECH FIG 4 • A-C. Arterial repair is performed using the operating microscope. A tension-free anastomosis of normal intima to normal intima is essential for survival of the replanted part. D. The vascular approximating clamp should have less than 30 g of closing pressure. Two clamps on a sliding bar allow for tension-free positioning of the vessel ends.
If adequate blood flow is not obtained, evaluate for all reversible causes of vasospasm, including hypotension, hypovolemia, acidosis, pain, or cold. Double check that the tourniquet was deflated.
Evaluate the proximal vessel for mechanical constriction.
Thoroughly irrigate the lumen with warm heparinized Ringer lactate through a 30-gauge blunt-tipped needle on a 10-mL syringe.
If vasospasm persists, irrigate the proximal vessel with papaverine solution (diluted 1:20 with sterile normal saline).
After appropriate blood flow is established, the proximal and distal stumps are placed within the vascular approximators. Several types of approximating devices are available. We favor two clamps on a sliding bar. The clamps should have less than 30 g of closing pressure and should be limited to no more than 30 minutes of application time due to the potential for vessel damage (TECH FIG 4D).
Place a microsurgical background deep to the repair site.
A bolus of 3000 to 5000 U of intravenous heparin is given just before the anastomosis. After the bolus, we typically initiate a heparin drip at 1000 U per hour.
Repeat inspection of the intima is performed proximally and distally to confirm its integrity. Verify that the anastomosis is tension-free and that no adventitia overhangs the lumen.
Appropriately sized monofilament nylon sutures (Table 1) are used and initial sutures are placed 180 degrees apart.
The size of each “bite” should be about one to two times the thickness of the arterial wall. Care must be taken to avoid damaging the intima of the vessel.
One limb each of the initial sutures should be cut long for use in manipulating the vessel without directly handling it.
Suture the front wall of the artery sequentially between stay sutures.
Irrigate the lumen after each suture is tied, and inspect the repair site to confirm that the back wall was not captured.
Flip the approximating clamp to expose the back wall and complete the anastomosis.
Remove the vessel from the approximating clips and repeat the procedure on the other digital artery.
Site of Repair
Suture Size
Needle Size (μm)
Palm
9-0
100
Proximal digit
10-0
75
Distal digit
11-0
50
Table 1 Needle and Suture Sizes
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Nerve Repair
The proximal and distal nerve ends are examined under the operating microscope.
The ends are cut sharply with a no. 11 blade against a wooden tongue depressor. The nerve is resected until pouting fascicles are visualized.
The fascicles are aligned, and an epineurial repair is performed using two or three 9-0 or 10-0 sutures (TECH FIG 5).
If a tension-free repair is not possible, primary nerve grafting is performed. The medial antebrachial cutaneous nerve is the ideal caliber for digital nerves and can be obtained from the ipsilateral extremity. Similarly, any amputated digits that are not candidates for replantation provide an excellent source for grafts.
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TECH FIG 5 • A,B. The digital nerve is approximated using an epineurial repair consisting of two or three sutures.
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Vein Repair
Ideally, a minimum of two veins are repaired for each artery.1,7 The largest veins identified should be repaired.
When performing the anastomosis, each bite should be about two to three times the thickness of the vein wall.
Constant irrigation with heparinized Ringer lactate helps to “float” the lumen of the vein open.
Due to the low-pressure flow, the venous anastomosis can be performed with fewer sutures than are required for the arterial anastomosis (TECH FIG 6).
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TECH FIG 6 • The venous anastomosis is performed with fewer sutures than the arterial repair due to the low-pressure flow.
Familiarity with alternatives to venous anastomosis is necessary in the event suitable veins cannot be located.
Continuous venous oozing can be encouraged by removal of the nail with subsequent scraping of the matrix. This scraping is performed every 2 hours with a cotton-tipped applicator and is followed by the application of heparinsoaked pledgets.
If proximal veins are present but distal veins are not, creation of either an arteriovenous or venocutaneous fistula may facilitate outflow to reduce congestion. This scenario is most common in very distal amputations just proximal to the nail. An arteriovenous fistula may be created possibly if one artery has been successfully repaired and back bleeding is present from the other distal artery. This artery can be anastomosed to the proximal vein. Alternatively, a vein graft can be used to create a temporary shunt from the skin of the pulp to the proximal vein.
Medicinal leeches (Hirudo medicinalis) can be placed on the engorged part if postoperative venous congestion occurs. They should be changed every few hours and should be used for a minimum of 7 days to allow for the establishment of collateral circulation. Although the leeches may fall off after engorgement, they secrete hirudin, a local anticoagulant that keeps the digit bleeding for 8 to 12 hours. While using leech therapy, the patient should be treated with a third-generation cephalosporin as prophylaxis against
Aeromonas hydrophila infection, a symbiotic gram-negative rod in the leech gut.
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Skin Coverage and Wound Closure
Before the wound is closed, meticulous hemostasis must be achieved. Even small postoperative hematomas can compress the vascular repairs and result in failure of the replant.
Interrupted nylon sutures are used to close the wounds, avoiding constriction of underlying structures. The midlateral incisions can be left open without concern for healing difficulties. If the repaired dorsal veins lack local coverage, a split- or full-thickness graft should be applied.
No part of the postoperative dressing should be circumferential. Small strips of petroleum-impregnated gauze are applied to the incisions. A bulky dressing is constructed with a plaster splint extending above the elbow. The tips of all digits must remain exposed, and a temperature probe is taped to the pulp of the replanted digit for monitoring.
The limb is elevated in a foam pillow.
PEARLS AND PITFALLS
Amputated
parts
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Take the amputated parts to the operating room to begin débridement and
identification of structures as soon as the room is ready.
Heterotopic
replantation
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Prioritize the functional goals for replantation. If multiple digits are amputated, but not
all parts are suitable for replantation, put the salvageable digits in the most functional position (eg, replant a finger in the thumb position if the thumb cannot be saved).
Vein grafts
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If there is concern for intimal damage, resection and the liberal use of vein grafts
saves time and frustration. Always reverse the vein graft in case valves are present in the segment. The volar aspect of the wrist contains numerous veins 1-2 mm in diameter.
Spare parts
surgery
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Never discard any amputated parts until the conclusion of the case. Amputated parts
that are not suitable for replantation are an ideal source of autologous grafts.
Vascular
anastomosis
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Never perform an anastomosis under tension. Either additional bone shortening or
vein grafting should be performed.
Multiple digit ▪ The overall duration of surgery is decreased by performing a structure-by-structure
replantations repair instead of a digit-by-digit repair (ie, repair the same anatomic structure in all
digits before repairing the next structure).3
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POSTOPERATIVE CARE
Usually, the hand is elevated, with the level of elevation adjusted for changes in vascular status. If arterial inflow becomes problematic, the hand is lowered. If venous congestion is present, the hand is raised.
Color, warmth, turgor, and capillary refill are monitored by the surgeon.
The patient's room should be kept warm, preferably above 22° C (72° F). The temperature probe is monitored by the nursing staff, and the surgeon is notified if the digital temperature is less than 30° C or if the temperature drops 2° C over 1 hour.
The patient is maintained on bed rest for the first 2 or 3 days, and the room is kept dark with minimal stimulation. Visitors are limited to two at a time.
The patient is restricted from nicotine and caffeine products.
The intravenous heparin drip is continued at 1000 U per hour. The rate is adjusted for a goal activated partial thromboplastin time (aPTT) of 1.5 times normal. It is maintained for 5 days, then weaned by 100 U per hour until off.
Dextran 40 is given as a 50-mL bolus and then maintained at a rate of 20 mL per hour while the patient is in the hospital.
Enteric-coated aspirin (325 mg daily) and dipyridamole (50 mg three times a day) are initiated and maintained for 6 weeks postoperatively.
Chlorpromazine (25 mg orally every 8 hours) is useful as both an anxiolytic and a peripheral vasodilator. We generally use it for the duration of the patient's hospital stay.
Appropriate antibiotics are maintained for 7 days.
We prefer to leave the operative dressing in place for 7 days to avoid causing vasospasm. Excessive bleeding with formation of a blood cast that would restrict venous outflow should prompt an earlier dressing change.
Gentle active motion is started on postoperative day 3 within the confines of the splint. Formal hand therapy is initiated after the splint is removed.
OUTCOMES
A survival rate greater than 80% is expected for replantation surgery.
Functional outcomes are greatest for replantation of the thumb, proximal hand, and single digit distal to the FDS insertion (FIG 6A-D).5,6,13,16
Recovery of sensation is correlated with function. As in other peripheral nerve injuries, age is the most important factor for recovery, with better results in younger patients. The average two-point discrimination in
replanted thumbs is 11 mm and in fingers is 8 mm.4 These values represent the average recovery for sharp amputation. Crush and avulsion mechanisms result in poorer two-point discrimination.
Range of motion is related to level of amputation. Active PIP joint motion in replantations proximal to the FDS insertion average 35 degrees, whereas replantations distal to the FDS insertion result in 82 degrees of PIP
joint motion (FIG 6E-G).7
COMPLICATIONS
Immediate Complications
Immediate complications affect the survival of the replanted digit and typically relate to the vascular status.
Arterial insufficiency may result from unrecognized vessel injury away from the anastomosis, which causes thrombosis or vasospasm.
A check for reversible causes is initiated to ensure that the patient is warm, comfortable, hydrated, and calm.
Check the dressings to confirm that there is no mechanical constriction.
Confirm that the patient's hematocrit is near normal and that all ordered medications are being given appropriately.
The hand should be lowered to increase inflow, and an intravenous bolus of heparin (3000 to 5000 U) is given. If the patient has not been anticoagulated or has not achieved therapeutic levels, a regional sympathetic block will aid peripheral vasodilation.
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FIG 6 • A-D. This patient sustained an amputated thumb, which was successfully replanted with good cosmetic and functional results. E-G. Successful replantation of the ring and small fingers resulted in a functional hand capable of holding common objects.
Vigilant reexamination of color, warmth, turgor, and capillary refill is necessary to decide whether exploration in the operating room is indicated. Revisions after 4 to 6 hours of reduced perfusion
seldom result in digit salvage.7
If venous engorgement occurs postoperatively, elevate the hand and remove constrictive dressings (including sutures that are too tight).
Consideration for return to the operating room is based on intraoperative findings affecting the possibility of revising the venous anastomosis.
If this is not possible, leeches or nail removal are used to alleviate venous congestion. These methods typically are used to bridge the first 4 to 6 days until adequate outflow is established.
Long-term Complications
Long-term complications include pin tract infections, cold intolerance, stiffness, malunion, and nonunion.
Pin tract infections usually occur more than 4 weeks after surgery. They are easily treated by pin removal and a course of oral antibiotics.
Cold intolerance is almost universal. (This also is a problem in revision amputations.) Cold intolerance is expected to improve over the first 2 years, but it remains debatable whether it completely resolves.2,14 Digital stiffness is common because both the flexor and extensor tendons are repaired. Tenolysis should be delayed for at least 3 months postreplantation but has demonstrated good results.9
Malunion usually results from malalignment at the time of bone fixation. Intraoperatively, rotational alignment is the most difficult to assess. Malunion is more common in proximal amputations because even slight malalignment at the amputation level is greatly accentuated at the fingertip.
Nonunion is not common after replantation of the digit. It has been reported in fewer than 10% of digit replantations and rarely requires reoperation.15,16
REFERENCES
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Allen DM, Levin LS. Digital replantation including postoperative care. Tech Hand Up Extrem Surg 2002;6:171-177.
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Backman C, Nyström A, Backman C, et al. Arterial spasticity and cold intolerance in relation to time after digital replantation. J Hand Surg Br 1993;18:551-555.
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Glickman LT, MacKinnon SE. Sensory recovery following digital replantation. Microsurgery 1990;11:236-242.
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Goldner RD, Howson MP, Nunley JA, et al. One hundred eleven thumb amputations: replantation versus revision. Microsurgery 1990;11:243-250.
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Goldner RD, Stevanovic MV, Nunley JA, et al. Digital replantation at the level of the distal interphalangeal joint and the distal phalanx. J Hand Surg Am 1989;14:214-220.
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Goldner RD, Urbaniak JR. Replantation. In: Green D, Hotchkiss RN, Pederson WC, et al, eds. Green's Operative Hand Surgery, ed 5. Philadelphia: Elsevier Churchill Livingstone, 2005:1569.
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Hattori Y, Doi K, Ikeda K, et al. A retrospective study of functional outcomes after successful replantation versus amputation closure for single fingertip amputations. J Hand Surg Am 2006;31:811-818.
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Jupiter JB, Pess GM, Bour CJ. Results of flexor tendon tenolysis after replantation in the hand. J Hand Surg Am 1989;14:35-44.
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Lucas GL. The pattern of venous drainage of the digits. J Hand Surg Am 1984;9:448-450.
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Matsuzaki H, Yoshizu T, Maki Y, et al. Functional and cosmetic results of fingertip replantation: anastomosing only the digital artery. Ann Plast Surg 2004;53:353-359.
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Ozkan O, Ozgentas HE, Safak T, et al. Unique superiority of microsurgical repair technique with its functional and aesthetic outcomes in ring avulsion injuries. J Plast Reconstr Aesthet Surg 2006;59:451-459.
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Patradul A, Ngarmukos C, Parkpian V. Major limb replantation: a Thai experience. Ann Acad Med Singapore 1995;24(4 suppl):82-88.
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Povlsen B, Nylander G, Nylander E. Cold-induced vasospasm after digital replantation does not improve with time: a 12-year prospective study. J Hand Surg Br 1995;20:237-239.
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Urbaniak JR, Hayes MG, Bright DS. Management of bone in digital replantation: free vascularized and composite bone grafts. Clin Orthop Relat Res 1978;(133):184-194.
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Urbaniak JR, Roth JH, Nunley JA, et al. The results of replantation after amputation of a single finger. J Bone Joint Surg Am 1985;67(4):611-619.
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Van Beek AL, Kutz JE, Zook EG. Importance of the ribbon sign, indicating unsuitability of the vessel, in replanting a finger. Plast Reconstr Surg 1978;61:32-35.
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Waikakul S, Sakkarnkosol S, Vanadurongwan V, et al. Results of 1018 digital replantations in 552 patients. Injury 2000;31:33-40.
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Wei FC, Chang YL, Chen HC, et al. Three successful digital replantations in a patient after 84, 86 and 94 hours of cold ischemia. Plast Reconstr Surg 1988;82:346-350.