REPLANTATION
Replantation is defined as the
reattachment of a completely severed part. The first successful replantation of
an above-elbow amputation was reported in 1962 by Malt and McLehman. In 1965,
Komatsu and Tamai reported the successful replantation of a thumb. The development
of this type of microsurgery has been greatly aided by advances in optical
instrumentation and especially in the manufacture of needles and sutures fine
enough to repair vessels 1 mm in diameter or less. Replantation is not suitable
or possible for all patients with amputations. Great care must be given to the
assessment of patients and their requirements. The surgical technique is
exacting and the postoperative care prolonged and difficult. However, with an
experienced team and a well-informed and motivated patient, the procedure can
produce good functional and cosmetic results.
Amputations and replantations are categorized as major
or minor. A major amputation involves muscle and is treated differently from a
minor amputation, which involves tendons but no muscle. Because both types of
amputation require great expertise and special surgical techniques, patients
with amputations should be referred to centers where such resources are
available.
Indications
The decision to undertake replantation of a severed
part is influenced by many factors, especially the level and mechanism of the
amputation and, equally important, the needs and desires of the patient. There
are no hard-and-fast rules to help in this decision. The patient and the family
must be fully informed about the possible outcomes and consequences of
replantation in terms of hospitalization, postoperative care, and hand therapy.
In a child, replantation of any amputation should
probably be attempted. In adults, replantation is indicated for amputation of
the thumb, multiple digits, hand, distal forearm, or single digit distal to the
insertion of the flexor digitorum superficialis tendon. Replantation should be
considered whenever the amputated part is crucial to hand function or when good functional
restoration of the part can be expected.
Contraindications
The only absolute contraindication to replantation is
a health condition, either a preexisting illness or associated injuries, that
precludes a prolonged surgical procedure. Treatment of other severe injuries,
which often accompany a
major amputation, obviously takes priority over the replantation effort.
Relative contraindications are numerous and can be either patient related or
injury related.
Systemic Illness
Diabetes, renal failure in a patient treated with
dialysis, generalized vascular disorders of the upper limb, and advanced
connective tissue disease all reduce the likelihood of a successful outcome because of
associated microvascular damage and possible vessel thrombosis.
Multiple Level Injuries
Replantation is rarely successful when there is wide-
spread vascular damage due to multiple level injuries. If the injury is both
above and below the elbow, however, every attempt should be made to save the
elbow because the presence of the joint improves the function of a prosthesis.
Extreme Contamination
Replantation is contraindicated when both the stump
and the amputated part have been inoculated with soil bacteria (particularly
with Clostridium species). This degree of contamination is common in
some farm injuries and in war injuries.
Age
The patient’s age alone is not a contraindication to
replantation, but it must be taken into account. Although the tiny size of
infants’ vessels reduces the chance that the replanted part will survive, the
function gained by a successful replantation is often quite good. In elderly
persons, useful or functional recovery is not a realistic expectation. Even in
patients with mild degenerative joint disease, postoperative edema and the
required postoperative splinting lead to stiffness in the whole hand.
Therefore, replantation in an elderly patient must be carefully considered.
Amputation of Single Digit
Replantation of a finger amputated proximal to the
insertion of the flexor digitorum superficialis tendon on the middle phalanx
may be contraindicated because motion is limited by the severe scarring and
tendon adhesions that develop after replantation. The index finger is not an
essential finger; if the return of function or sensation after replantation is
poor, the patient may prefer to use the normal adjacent middle finger for tasks
usually accomplished with the index finger. A stiff little finger does not flex well in power grip, often
catching in clothing. The benefits of replantation of either of these digits
must therefore be carefully assessed.
Avulsion
The likelihood of successful replantation of digits or
limbs torn from the body is poor because of the extent of injury and the amount
of dissection needed to escape the zone of injury. A red line on the skin overlying the neurovascular
bundle of a digit suggests an extensive avulsion of these structures and a poor
chance of recovery. Ring avulsions are the most difficult avulsion injuries to
replant. Even major vessel repair may not revascularize the devascularized
flexor tendons and proximal interphalangeal joint; and although the finger may
be successfully replanted, it often becomes stiff and atrophic. A revision amputation may be a better
treatment choice, especially in the older patient.
Prolonged Ischemia
Either warm (32°C) or cold (5° to 10°C) ischemia
seriously reduces the likelihood of a successful replantation. Unfortunately,
studies have not yet shown what duration of warm or cold ischemia is critical.
Most amputated parts sustain some warm ischemia until medical help arrives.
Once the replantation procedure begins, the part goes through a second period
of warm ischemia until vascular continuity is restored. Cooling (cold ischemia)
to about 10°C clearly helps to preserve the amputated part. Given adequate
cooling, major replantations have been successfully performed 8 to 16 hours
after amputation and minor replantations have been successful even after 18 to
30 hours.
Preoperative Management
Treatment at the scene of the accident and at first
medical contact strongly affects the outcome of later replantation. Improper
handling of the amputated part or stump can seriously compromise the final
result. The initial assessment of the patient’s status must exclude any
life-threatening injuries, particularly if a major amputation is involved. The
patient must be hemodynamically stable before either transportation or
replantation is attempted.
Once the patient’s safety is ensured, the stump is
cleaned of gross contamination and protected with a sterile compression
bandage. Bleeding after amputation is rarely a problem because fully transected
vessels usually contract. If bleeding persists, however, it should never be
stopped with the blind application of a hemostat, because this may further
damage the neurovascular structures. Elevation of the stump usually stops the
bleeding. A tourniquet should not be used because unregulated pressure
increases the risk of ischemia and vascular damage.
The severed part is cleaned of any gross contamination
and foreign material and cooled to reduce its metabolic rate. A severed digit
should be wrapped in moist gauze and placed in a watertight plastic bag, which
is then immersed in ice water. The amputated part must not be allowed to come
into direct contact with any ice, and dry ice should never be used. Properly
cooled, a digit can be
successfully replanted within 30 hours of amputation.
With a major amputation, preparation of the severed
part is even more important. The amputated part is cleaned of all gross
contamination, wrapped in a moist towel, and placed in a plastic bag. The part
should be rapidly cooled to 10°C by immersing the plastic bag in ice water for 20 to 60 minutes. The part is then
placed in an insulated container (but not in contact with the ice) and
maintained at 10°C. Thus prepared, the amputated part is clearly labeled and
rapidly transported to the replantation center.
Cold ischemia can preserve muscle up to 8 to 12 hours,
after which irreversible changes may occur. Warm ischemia, which results from
improper cooling, can lead to irreversible changes in as little as 4 to 6
hours, thus preventing successful replantation. Several attempts have been made
to reduce ischemia time by perfusing the amputated limb with various substances
such as oxygenated fluorocarbon solutions. At present, the most reliable fluid
appears to be autologous arterial blood mixed with heparin. Perfusion plus
cooling may make major replantations possible as much as 12 to 16 hours after
injury.
In the emergency department, tetanus prophylaxis and a
broad-spectrum antibiotic are administered as soon as possible. A complete
history is obtained and a physical examination performed. Treatment options are
thoroughly discussed with the patient and family. The decision to replant or to
revise the amputation is based on the patient’s wishes, age, health, and
occupation; the type and level of the amputation; ischemia time; associated
injuries; and the surgeon’s experience.
Technique For Minor Replantation
Repair of Bone and Tendon
Ideally, every replantation center should have two
surgical teams available at all times. Once the decision to undertake
replantation is made, the severed part is taken to the operating room. While
one team prepares the patient for surgery, the other team thoroughly debrides the
amputated part, viewing it under magnification. All devitalized and heavily
contaminated tissue is excised, including frayed tendon ends, comminuted bone
fragments, but only a small margin of skin, because coverage is important and
skin is more resilient than deeper tissues. Frayed tendon ends are excised
because the damage to
the exposed tendon surfaces greatly increases the risk that adhesions will
subsequently form and restrict motion.
Bone is trimmed to (1) remove avascular bone that
could initiate the development of osteomyelitis; (2) provide flat, congruent
surfaces for stable bone fixation; and (3) provide the necessary skeletal
shortening to facilitate tension-free vessel anastomoses and nerve coaptations after debridement. At the digital or
metacarpal level, the bone may be shortened about 1 cm. In the arm or forearm,
the amount of bone shortening may be as much as 2 to 4 cm.
A severed part can be handled more easily while it is
detached from the body. An interosseous wire or a Kirschner wire can be placed
in the bone of the amputated part to facilitate later fixation. A tendon suture
of the Kirchmayr type (modified Kessler) can also be
inserted at this time. The distal arteries, veins, and nerves are identified
and tagged with fine sutures. Skin incisions are usually needed to expose these
structures. The volar aspect of the finger is usually opened with a Brunner
zigzag incision. A straight midline incision is made on the dorsal aspect. Only
full-thickness skin flaps are reflected; the subcutaneous tissue and veins are
left intact for later dissection under microscopic visualization.
While the amputated part is being prepared, the
patient is transferred to the operating room and regional anesthesia is
administered (preferably an axillary block). Regional anesthesia provides some
sympathetic blockade and vasodilation as well as pain relief. The arm is
cleaned with antiseptics, draped, and exsanguinated. The surgeon thoroughly
debrides the stump, shortening the bone and tendon to permit easier anastomosis
of vessels and coaptation of nerves. Use of a tourniquet facilitates the
debridement. Once corresponding structures in the stump and the amputated part
have been identified, replantation is begun. Because stability is essential for
the vascular reconstruction, bone fixation is carried out first.
The technique of bone fixation should be appropriate
for the type and level of amputation and provide stable fixation for early
mobilization. Fixation devices include interosseous wires, Kirschner wires, and
compression plates and should minimize further soft tissue disruption.
Replantation at the phalangeal level can be secured
with interosseous wires with or without the added stability of a Kirschner
wire; some surgeons prefer to use crossed Kirschner wires. Replantations at the
joint level require a removable fixation device if the joint is to be
preserved; otherwise, any standard technique for arthrodesis of small joints is
suitable. At the metacarpal or more proximal level, a compression plate is
preferred. If contamination is significant, however, an external fixator should
be used to reduce the risk of infection. If possible, the periosteum is
repaired to help bone healing
and minimize adhesions to the flexor and extensor tendons. Kirchmayr (Kessler)
sutures are used to repair flexor tendons, and interrupted figure-of-eight
sutures are used for extensor tendons.
Repair of Blood Vessels and Nerves
After repair of bone and tendon, microvascular clamps
are applied to the prepared arteries and veins, the tourniquet is released, and the blood flow is noted.
This is the only way to assess arterial inflow. If arterial bleeding from the
stump is not pulsatile after the arterial clamp is released, further resection
of the artery is required to bypass the zone of injury. The distal artery and
vein must be resected to remove all damaged tissue. Vein grafts are inserted to
bridge the gap produced by the resection if the vessels cannot be anastomosed without tension. When used for repairing arteries,
vein grafts are reversed so that valves do not impede the flow of blood.
Repairing rather than resecting injured and compromised vessels to avoid use of
vein grafts almost always ends in failure because thrombosis occurs almost
immediately in these injured vessels.
The surgeon’s preference dictates whether repair of
the arterial or the venous system is performed first. Generally, the arteries
are repaired first to reduce ischemia time and to allow the surgeon to assess
the adequacy of the venous debridement and determine which veins are best
suited for repair. Ideally, both arteries and at least three veins are repaired
in each digit.
Once the finger is revascularized, the nerves are
repaired in standard fashion. Tendons are then repaired by tying the two core
stitches in each end, adding a second core stitch and then an epitendinous
repair. Then the skin is loosely approximated to avoid constriction of the
vasculature when postoperative edema develops. Skin grafts or flap coverage
should be used if primary closure is not possible and typically done
secondarily within the initial hospital stay. For example, the lateral forearm
rotation flap or free flow-through flap (see Plate 4-65) can be used to cover skin defects to the thumb after replantation. Use
of normal skin and subcutaneous tissues from an uninjured zone brings excellent
vascularity to the compromised digit.
Replantation of multiple digits is carried out in a
similar sequence. One finger is completed at a time, while the other fingers
are kept cold. However, nerve and tendon repair is often delayed until all
digits are replanted and successfully perfused. If all the fingers are
replanted together (i.e., bone fixation completed, then all tendons sutured,
then blood vessels and nerves repaired), the prolonged duration of warm
ischemia under the microscope lights may compromise the final result.
Postoperative Dressing
After replantation of fingers, a bulky dressing is
applied to splint and protect the finger and hand in a position that enhances mobility, taking into account the
delicate nature of the surgical repairs. The elbow should be flexed and the
fingers pointing to the ceiling for edema control. The ideal position for
postoperative immobilization is with the metacarpophalangeal joints in 70
degrees of flexion, with interphalangeal joints in neutral position, and with the
thumb in maximal volar abduction. If this position is not possible, the
alternative position used should come as close as possible to the ideal yet not stress or compress the vascular repairs. The
dressing should be applied to allow easy visual inspection and temperature
monitoring of the finger yet guard against excessive manipulation of the finger
itself.
Secondary Reconstruction
One-stage reconstruction (primary repair or grafting
of all divided structures) is the preferred treatment because it avoids
scarring from additional surgical procedures and because the patient can
concentrate on rehabilitation after surgery. However, some procedures cannot be
effectively completed at the time of replantation. Rarely, a replanted part is
stiff, painful, useless, and ugly, and the patient may benefit from
reamputation. Secondary reconstruction is much more common after major
replantations than after minor replantations. The most common secondary
procedures are bone grafting to treat a nonunion, soft tissue surgery to
correct scar deformity at the amputation site, tenolysis to restore motion, and
nerve grafting to improve sensation. Most often, however, patients require
muscle and tendon transfers to restore function after poor recovery after nerve
repair.
A toe-to-hand transfer is recommended when an
additional digit would significantly improve hand function (see Plate 4-66). Because the transplanted toe never functions as well as the original
finger, patients must first appreciate the deficit created by the missing
finger before they can accept the reconstructed digit.
Results
Results of replantation must be interpreted with great
care and compared not with normal function but with function with the best
prostheses. Replantations often survive, but the more important outcome subsequent hand and limb function is not well reported. For example, the person who
cannot return to work because a replanted finger is stiff and painful has a
much greater disability than someone who has a well-performed revision
amputation and can return to work 4 weeks after surgery.
Generally, functional recovery is determined by nerve
regeneration, which tends to be better in patients younger than 35 years of age
with more distal amputation sites. However, good recovery is often seen in
young patients with more proximal amputations.
Regarding nerve regeneration, different parts of the
hand have different functional requirements. For example, the thumb and index
finger require good sensation and stability, whereas the three ulnar digits
require motion for power grip and are less involved in sensation. A comparison of functional assessments of
replantations is difficult because patients’ needs with respect to mobility and
stability vary. However, most patients are satisfied with the replanted part
and report that they
would choose the procedure again.
