Types of wound
A closed blunt injury may result in a bruise
or contusion. There is bleeding into the tissues and visible discoloration.
Where the amount of bleeding is sufficient to create a localised collection in
the tissues, this is described as a haematoma. Initially this will be fluid, but
it will clot within minutes or hours. Later, after a few days, the haematoma
will again liquefy. There is a danger of secondary infection. Bruises require no
specific management, and no treatment is of proven value. The patient should be
advised that the time required for bruising to clear is extremely variable and
in some individuals, in some sites, discoloration may persist for months. A
haematoma should be evacuated by open surgery if large or causing pressure
effects (such as intracranially), or aspirated by a large-bore needle if smaller
or in a cosmetically sensitive site. It may be necessary to await liquefaction
(which may take several days) and to perform repeated aspirations, with
appropriate antiseptic precautions. A haematoma will generally reabsorb
without scarring, but on occasions there may be persistent tethering of the
skin. Blunt injuries may cause a variety of fat injuries. A blunt injury to the
breast may result in an area of fat necrosis that can masquerade as a breast
lump. Blunt injuries to the face may result in lumpy subcutaneous collections
due to haematoma in subcutaneous fat that may persist for several months. A fat
‘fracture’ in the buttocks may result from a fall or sharp blow. This can
result in separation of subcutaneous fat with an indentation that may not become
apparent immediately due to haematoma.
A puncture wound is an open injury in which
foreign material and organisms are likely to be carried deeply into the
underlying tissues. Common causes are standing on a nail or other sharp object.
There may be little to see on the surface. Radiological examination may detect
metal fragments or glass. Treatment is essentially by wound irrigation,
antibiotic treatment and tetanus prophylaxis. Large foreign bodies should be
removed, but small particles may be surprisingly difficult to find without a
destructive dissection and are better left undisturbed. When a foreign body is
visualised on
Abrasions and
friction burns
An abrasion is a shearing injury of skin in
which the surface is rubbed off. Most are superficial and will heal by
epithelialisation,
but some may result in full-thickness skin loss. Abrasions may be dirt ingrained
and if this dirt is not removed at the time of primary treatment permanent
tattooing of the skin will result. Treatment is by cleaning with a scrubbing
brush, gently brushing along the grain of the scratch lines. A friction burn is
similar, but there will be an element of thermal damage as well as abrasion.
Treatment is as for other types of burn.
Laceration
A laceration or cut is the result of contact
with a sharp object (the surgical equivalent is an incised wound). Once the
cutting
implement has gonc deep to the dermis, there is less resistance in the
subcutaneous tissues and the cut may therefore penetrate to a considerable
depth. It is important to ascertain from the history the amount of force
involved. The clinical examination must therefore assess the integrity of all
structures in the area: arteries, nerves, muscles, tendons and ligaments (Fig.
3.6). The ideal form of management of an incised wound is surgical inspection,
cleaning and closure. The wound must be thoroughly inspected to ensure that
there is no damage to deep structures or, where encountered, these must be
repaired (Fig. 3.7). As a general rule, the damage to nerves and tendons is
generally greater than suspected preoperatively. Once all of the damaged
layers have been identified, each structure must be repaired individually by the
appropriate technique. Haemostasis must be ensured throughout the exploration.
There are precise suture placement techniques for nerves, tendons and blood
vessels. Muscles can be apposed in layers by mattress sutures and fascia, and
subcutaneous fat should be opposed by interrupted absorbable sutures to allow
a firm platform for skin closure in such a way that the skin margins do not
invert. It is an important principle to prevent collections of blood or other
fluids in a wound as they separate tissues and act as a nidus for infection. A
corrugated or suction drain may be required. In a simple incised laceration, a
method of wound closure should be selected which is appropriate for the needs of
function and appearance. On the face, fine (5/0
or 6/0) nylon sutures should be placed near to the wound margins, to be
removed on the fifth day. Alternatively, subcuticular (intradermal) sutures
avoid suture marks and can be left in place longer (2 weeks or more). An
alternative to suturing is the application of adhesive tape strips. It is
necessary to apply these with the same care as sutures ensuring that all
bleeding has stopped and that the skin is dry. For limb and trunk wounds, a
heavier suture is required but it is rarely necessary to use more than 4/0 or
3/0 sutures for skin closure. Monofilament sutures, such as nylon, are said to
leave less obvious suture marks than braided material such as silk, but other
factors contribute to stitch marks, such as inflammation (from infection or
reaction to organic material such as silk),
Avulsion injuries are open injuries where
there has been a severe degree of tissue damage. Such injuries occur when hands
or limbs are trapped in moving machinery, such as in rollers, producing a
degloving injury. Degloving is caused by shearing forces that separate tissue
planes, rupturing their vascular interconnections and causing tissue ischaemia.
This most frequently occurs between the subcutaneous fat and deep fascia.
Degloving injuries can be open or closed. Degloving can be localised or
circumferential. It can occur only in the single, subcutaneous plane, but where
present in multiple planes, such as between muscles and fascia and between
muscles and bone, is an indication of a severe high-energy injury with a limited
potential for primary healing. Similar injuries occur as a result of runover
road traffic accident injuries where friction from rubber tyres will avulse skin
and subcutaneous tissue from the underlying deep fascia (Fig.
3.11). The history
should raise the examiner’s suspicion and it is often possible to pinch the
skin and lift it upwards revealing its detachment from the normal anchorage. The
danger of degloving or avulsion injuries is that there is devascularisation of
tissue and skin necrosis may become slowly apparent in the following few days.
Even tissue that initially demonstrates venous bleeding may subsequently undergo
necrosis if the circulation is insufficient. Treatment of such injuries is to
identify the area of devitalised skin and to remove the skin, defat it and
reapply it as a full-thickness skin graft. Avulsion injuries of hands or feet
may require immediate flap cover using a one-stage microvascular tissue
transfer of skin and/or muscle.
Crush
Crush injuries are a further variant of blunt
injury and are often accompanied by degloving and compartment syndrome. Injury
to tissues within a closed fascial compartment leads to bleeding, exudate and
swelling of these tissues, and increased interstitial pressure. As the
interstitial pressure rises above capillary perfusion pressure the blood
supply’ to the viable tissues is reduced, resulting in further ischaemic
tissue injury and swelling (Fig. 3.12). This cycle causes a worsening
compartment syndrome with muscle ischaemia and nerve ischaemia progressing to
muscle necrosis, skin necrosis and limb loss. Muscle necrosis may result in
renal failure. This process can be arrested by early recognition and
decompression
of the affected compartment(s) by fasciotomy. The most reliable clinical sign of
compartment syndrome is pain worsened by passive stretching of affected
muscles. Where any doubt exists compartment pressure measurements can be carried
out. Loss of peripheral pulses is not a sign of compartment syndrome, but
indicates major vessel damage. Where compartment syndrome is suspected or
confirmed fasciotomy is advised. Longitudinal incisions are made in the deep
fascia and it may also be necessary to make extensive longitudinal releases in
the skin. It is important to release the fascia over each individual compartment
in a limb.