REPLANTATION

The sequence of repair of the severed structures in
replantation will vary slightly depending on the level of amputation
(digit versus levels proximal to the wrist) and type of injury (sharp
versus avulsion). The technique of replanting amputated digits is
described first because these amputations are much more common than the
more proximal amputations. The variations in technique used for major
limb replantations are described subsequently.

Repair for digit and hand replantation takes place in the order indicated in Table 34.2.

Once the vessels and nerves are located and tagged, protect these neurovascular structures during the debridement. Do
not, in haste to reestablish blood flow, compromise on the irrigation
and debridement. A thorough wound debridement is essential. A pulsating jet lavage is useful in severely contaminated major limb replantations.

Excise all necrotic and potentially necrotic tissue, particularly muscle.

All structures are repaired primarily, even if primary nerve grafting is necessary for approximation of the severed nerves
It is much easier to make repairs at the time of the initial
reconstruction than to reoperate secondarily through the repaired
structures of the replanted part.

Never anastomose arteries, veins, and nerves under tension
Sufficient bone must be resected to ensure the ease of approximation of
normal intima in the vascular anastomosis. Additionally, bone
shortening allows easier skin coverage of the repaired veins,
particularly on the dorsum of the digits. The amount of resected bone
depends on the type of injury. In an avulsion or crushing type of
injury, more bone must be resected until normal intimal coaptation is
possible without tension. For the digit, it is usually necessary to
resect 5 to 10 mm of bone; in amputations proximal to the hand, 2 to 3
cm of bone resection may be indicated. In the avulsion type of injury,
even more bone resection is done. If it appears that a great deal of
bone must be resected in the digit or in partial hand amputations, use vein grafts to make up the deficit in the arteries and veins rather than doing excessive bone shortening.

Many replantation surgeons emphasize that bone
shortening is seldom necessary, and instead they recommend vein
grafting when there is considerable intimal damage (52).
Bone shortening should usually be chosen over vein grafting, however,
because there is often concomitant damage to the nerves and other soft
tissues. These injured structures can be more easily managed after bone
shortening. However, do not hesitate to perform vein grafts when they
are indicated (for example, when the loss of a potentially functional
joint may result from bone shortening). This is particularly true for a
child, for whom excessive bone resection should be avoided because it
results in the excision or potential damage to the epiphysis and joint.
Do not hesitate to perform interposition vein grafts when they are
necessary; it is quicker, easier, and less
frustrating to perform an interposition graft than to redo a difficult
anastomosis several times, or even one time.

In replantation of the thumb, most of the bone
shortening is done on the amputated part to preserve maximal length on
the stump in case replantation fails. This is not always possible, as,
for example, when attempting to preserve joint function. Several
methods of bone fixation are available (Fig. 34.6) (41,79,86,97):

All these methods may be used to stabilize
replantations; however, certain methods may be preferred in specific
areas, such as near the joint or epiphyseal plates. When possible, it
is preferable to perform bone stabilization in a digit with double
axial Kirschner wires because the lowest nonunion and complication
rates occur with this method (97). This is the
easiest and quickest method when a motorized drill is used for careful
pin placement. A large-bore hypodermic needle (16-gauge) is often used
as a guide to prevent the surrounding soft tissue from

wrapping up near the bone ends. In
more than 1,800 replantations, we have experimented with all methods of
bone stabilization and prefer single or double axial Kirschner wire
fixation for the following reasons:

Crossed Kirschner wires can cause potential damage in
the repaired neurovascular bundles, either by contact or by tethering
of the vessels or the protective retaining ligaments. I prefer crossed
Kirschner wires for arthrodesis of joints. A chevron bone cut aids
stabilization when crossed Kirschner wire fixation or the tension
wiring is used.

For arthrodesis or fixation near the joint, cut the Kirschner wire at the cortex and leave it permanently implanted.

Intramedullary screw fixation is ideal for thumb
metacarpal stabilization in replanting a complete amputation at this
level. This method is easy and rapid and provides immediate stability.
Its use is limited in arthrodesis of other joints because some flexion
is usually desired. Immediate fixation allows early motion of the
digits; however, the screw is difficult to remove if the replanted
digit becomes infected. Bone pegs or other intramedullary devices can
be substituted for the screw. Intramedullary devices, however, are not
favored in highly contaminated wounds.

For intraosseous wiring, drill four drill holes at 12,
3, 6, and 9 o’clock in each end of the bone. Then place two strands of
24-gauge wire perpendicular to each other. This provides good stability
(86). It is particularly useful for fractures
in the metaphyseal areas or even for primary joint fusions. Immediate
or early motion is usually possible. It does take slightly more time
than intramedullary pins, but the amputated part can be prepared by
having the wires inserted in one end by one of the teams.

Plate-and-screw fixation is seldom indicated because
nonunion is rarely a significant problem in replantation of digits.
This method requires extensive bone exposure, with the possibility of
further soft-tissue damage, and it also requires more time. In major
limb replantation, however, it is the preferred method because of the
precision and rigid fixation obtained (10,32,61).

One of the most difficult problems, even for the
experienced hand surgeon, is obtaining proper digital alignment when
replanting multiple digits. This may present a problem even when
replanting a single digit. Check the relationships of the digits
frequently in extension and flexion. Observe the cascade and rotation
of fingertips; in general, when flexed, the fingertip should point to
the scaphoid bone. Most replantations do survive, so take great care to
achieve anatomic alignment and rotation of the replanted parts. In
adults there are occasional indications for primary silicone implant
arthroplasty with replantations at the joint level, such as an effort
to save proximal interphalangeal joint function in a musician. This is
particularly the case if one of the central digits (long or ring
finger) is amputated at the proximal interphalangeal joint level. It is
actually quicker and easier to perform a silicone implant arthroplasty
than a primary fusion; however, the indications are not common. In
addition to bone stabilization, whenever possible try to repair the
periosteum, capsule, and ligamentous structures to provide better
gliding of joints and tendons and to promote joint stability.

Make every effort to preserve joints in children.

To provide additional stability, always repair extensor
tendons primarily, just after bone stabilization. Use surgical loupes
in extensor tendon repair, and keep in mind the following procedures:

Attempt primary flexor tendon repair in almost all
replantations. Secondary repair is rather difficult because of the
excessive scarring around the repaired nerves, vessels, and joints.
Secondary flexor tendon repair in replanted digits usually requires a
two-stage silicone rod procedure in digits other than the thumb.
Because this procedure amounts to two additional surgical procedures,
it is wise to attempt primary repair as follows.

For retrieval of proximal stumps of flexor tendons, observe the following directions:

Another reason for performing primary flexor tendon
repair is to relieve any undue compression or tethering of the proximal
vascular tree that could be caused by proximal retraction of the
severed flexor tendons.

Use a suture method in primary flexor tendon repair, with the following recommendations:

Some primary repairs of flexor tendons in replanted
digits may require subsequent tenolysis; however, do not do a tenolysis
for at least 3 to 6 months after the primary repair.

If a delayed flexor tendon repair is necessary, it may
be safely performed as long as 3 months after the initial replantation
or revascularization. Usually the two-stage silicone rod method is
indicated.

Nerve repair in replantation is usually not difficult
because the bone has been shortened, and no tension should be present
at the suture line.

After all of these structures have been repaired and successful revascularization of the replanted part has been ensured, meticulous hemostasis is essential. Failure to obtain complete hemostasis can lead to multiple postoperative problems and failure of the replant.

Because major limb amputations are usually severe
injuries with extensive muscle and other soft-tissue damage, a great
deal of soft tissue, including skin, muscle, tendon, and nerve, must be
excised if the replanted part is to survive without infection. It is
therefore prudent to shorten the bone considerably when possible.

In major limb replantation, it is critical to perform the arterial anastomosis before the venous anastomosis.
This sequence permits a physiologic washout of noxious agents, such as
lactic acid, in the distal part. If this order is reversed, with venous
repair first, the return of toxic metabolites to the systemic
circulation can cause serious consequences, even death. Giving
intravenous sodium bicarbonate before venous anastomosis is beneficial (23).

Fasciotomies are almost always necessary in major limb
replantation. A common error is failure to decompress the replanted
limb adequately, leading to myonecrosis with subsequent infection.
Meshed split-thickness skin grafts provide some coverage of exposed
vessels. Other areas may be closed primarily or grafted several days
later.

Keep the replanted part elevated in the bulky dressing,
and keep it warm at all times. The patient should stay in a warm,
comfortable room during the first week. If the recovery room is cooler
than normal room temperature, place a patient heater or a warmer over
the patient. Keep the patient’s room at a minimum of 72°F (22°C) and
prevent cool air drafts.

The use of anticoagulation therapy remains
controversial. A few surgeons use none or perhaps only aspirin and di-
pyridamole; some use all or various combinations of anticoagulants (11,52,57,104). We prefer some type of anticoagulation for all patients.

Heparin is generally not indicated in clean-cut
amputations that are replanted or if the anastomosis was technically
easy and the blood flow was immediately brisk. In these patients, we
use aspirin, 300 mg, and dipyridamole, 50 mg, twice daily as well as
500 mg of intravenous low-molecular-weight dextran for 1 week. In
addition, we give chlorpromazine, 25 mg three or four times daily, for
a tranquilizing effect as well as to provide peripheral dilation. This
drug is valuable in relieving vasospasms secondary to anxiety, which
occurs particularly in children. In children, the dose is reduced to 10
mg three to four times daily by mouth.

If the injury is of the avulsing or crushing type, give
intravenous heparin, 1,000 units every hour, in adults for 7 days.
Adjust this dosage in children, giving about 100 U/kg for 4 h. Adjust
this according to the activated partial thromboplastin time, which is
maintained at 1.5 times normal. If bleeding occurs into the dressing,
adjust the dosage and change the dressing immediately to prevent
constriction. Do not use heparin prophylaxis in amputations proximal to
the wrist level. Give appropriate antibiotics for 1 week.

Capillary refill, pulp turgor, color, and warmth are all useful indicators in monitoring the replant (39), but quantitative skin temperature measurements have proved the most reliable indicators (28,38,49,65,74). Monitor digital temperature with a telethermometer and small surface probes (Fig. 34.11).
The normal skin temperature of the digits is 31° to 35°C. Remember that
ambient temperature may influence the interpretation of the recordings.
Probes are usually placed on the replanted digits, on a normal digit
for control, and on the dressing for measurement of the ambient
temperature. An abrupt or even gradual change in temperature indicates
that the replant may be failing, and steps must be taken to improve the
blood flow. If the temperature drops below 30°C or shows more than a 2°
drop when compared with the normal digit, appropriate methods of
management must be undertaken immediately.

Bed rest or ambulation is determined by the activity
level or desire of the patient. If the patient is anxious and chooses
to remain in bed or appears to be having difficulty with blood flow to
the replanted part, then bed rest is advised for 3 to 5 days. If the
patient is vigorous or energetic, however, allow activity a day or two
after the replantation. Permit no smoking by the patient or in the
patient’s room, and all efforts should be made to keep the patient
tranquil (15).

Relatively early active joint motion is encouraged in most replantations (17,18,69);
because the dressing is not changed for at least 10 days, however,
immediate early motion is limited. In the patient who has had a
replantation distal to the superficialis insertion, encourage movement
of the digit the following day because there is really no stress on the
flexor or extensor tendons. Otherwise, begin protective active motion
against rubber bands and flexor and extensor outriggers, supervised by
a hand therapist, 1 to 2 weeks after the replantation. Especially for
replantation patients who live far from the treatment center, if more
than one digit has been replanted or a major limb has been replanted,
keep the patient in the hospital or in a nearby motel so that daily
therapy can be supervised by hand therapists.

Acute failures are secondary to inadequate perfusion (39). Often the surgeon can predict which replantation will have a postoperative problem with perfusion. Some examples include:

When these signs of jeopardy are present, extra
postoperative efforts are necessary to enhance the chances of survival.
Intravenous heparin is particularly beneficial in these difficult
replantations.

Although infections occur frequently in digital
replantations, loss of a replanted digit is rare secondary to
infection. The most common infections are pin tract infections, which
usually occur more than 4 weeks after the replantation and are easily
managed by removing the pins and putting the patient on antibiotics. We
have seldom found it necessary to admit a patient to the hospital for
pin tract infections.

Infection is more common and more serious in major limb
replantations. The presence of large amounts of muscle that have been
rendered ischemic increases the likelihood of infection. To ensure
adequate muscle debridement, return all major limb replantations to the
operating room in 48 h for a “second look” procedure. At this time,
inspect the wounds thoroughly and debride any muscle necrosis that has
progressed since the first procedure. Infections in major limb
replantations may not become apparent until the second week (most
commonly in 8 to 10 days); if the infection involves the vascular
anastomosis, failure is almost inevitable.

The most common chronic complications are cold intolerance, tendon adhesions, and malunion.

Cold intolerance is an almost universal complaint in
patients who have undergone digital replantations. However, cold
intolerance is not unique to digital replantation and occurs with
almost equal incidence in other severe hand injuries, including
amputations that are not replanted (29). Cold
intolerance is related to the adequacy of digital reperfusion; for this
reason, try to maximize the number of arterial repairs. Cold
intolerance diminishes with time and usually resolves by 2 years (91). Pain is rare in successfully replanted limbs.

Because both the flexor and extensor tendons are usually
repaired in replantations, tendon adhesions are common, with diminished
motion. If this is severe, tenolysis may be performed as early as 3
months after replantation.

Malunion is most often seen after transmetacarpal
replantation. These complex injuries require multiple tendon, vessel,
and nerve repairs, and if care is not taken during bone fixation,
rotational malunion may occur.

Every
effort should be made to properly align digits before replantation.
Another form of malunion can occur in multiple digit replantations for
which it is difficult to identify the various digits at the time of
surgery. It may become apparent later that one digit has been exchanged
for another. This is primarily a cosmetic problem and does not result
in any diminished function.

Nonunion is not a common problem after replantation: it has been reported to occur in only 2% to 9% of digital replantations (86,87). Usually nonunions are asymptomatic, and I have yet to operate on a patient for a nonunion of a digital replantation.