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The
goal of replantation (commonly known as re-implantation or re-attachment
surgery) after traumatic
amputation is successful restoration of
function.
Simply returning circulation to
an amputated part does not in itself
define success. The aim of the
both the patient and the surgeon is
useful function - replantation of a part
that will not perform useful activity
should be avoided.
Replantation of
amputated parts has been peformed in amputated fingers, hands,
forearms, feet, amputated ears, avulsed scalp injuries, an amputated
face, amputated lips, amputated penis and even in an amputated tongue.
These injuries can arise from multiple potential etiologies including
trauma (often industrial), machine injuries, assault or even
self-mutilation. We will focus on finger and upper extremity
replantation since they are much more common than other amputations
such as penis amputaion.
Decision
making in replantation must take
multiple factors into consideration.
Overview
of Technique of Replantation
Examination
and Dissection of the Amputated Part
The
amputated part is cleaned and prepped,
as is the affected arm. Using
magnification, the part and hand are
inspected to assess the extent of the
injury and the feasibility of
replantation. In the figure above,
the outlined long finger illustrates a
fairly sharp saw amputation. The
long finger is magnified below.
Bone
Fixation (Osteosynthesis)
If
the part is deemed to be replantable,
bone fixation is performed first.
Most commonly, fixation with k-wires is
performed. The wires span the site
where the bone has been cut, to hold the
bone in rigid fixation. They
usually exit the skin near the site of
bone injury. Plate fixation can
sometimes be performed if the anatomy
and surgeon comfort allow it.
Plate fixation involves screwing a
titanium alloy plate to the dorsal
aspect of the injured bone. The
advantages include no k-wire exit sites,
more rigid fixation and easier early
mobilization post-operatively.
Disadvantages include increased
operating time and the requirement for
increased bone stripping to expose bone
for plating.
Tendon
Repair
After
bone fixation is performed, the dorsal
extensor tendon (above) and flexor
tendon (below) are repaired. With
all the "macro" structures
repaired - bone, extensor and flexor
tendon - attention is then turned to the
microsurgical portion of the procedure.
Microsurgical
Artery and Nerve Repair
The
microsurgical repair of an artery can
now be performed with the operating
microscope. A digital vessel,
which is approximately 1 millimeter in
size, can be repaired with 6 to 8
sutures of nylon. Removal of the
vascular clamps reveals whether
circulation can be re-established to the
finger. Typically, an anticoagulant
is begun intravenously, like dextran.
Both digital nerves can then be repaired
microsurgically.
Microsurgical
Vein Repair
Attention
is then usually turned to the dorsal
aspect of the finger where the venous
system is present that drains blood from
the finger. Usually one or
occasionally two veins are repaired with
the operating microscope. The
veins are often much smaller and more
fragile than the arteries and hence more
prone to clotting post-operatively.
Skin
Closure and Splinting
The
skin is then closed, often with a skin
graft, depending on the swelling and the
nature of the injury.
The
hand is usually placed in a splint and
the patient is monitored closely for
circulatory changes in the finger during
the post-operative period.
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