DISORDERS OF WOUND HEALING
of wound healing in the burn patient result from ex-cessive abnormal healing or
inadequate new tissue formation. Hypertrophic scarring and keloid formation
result from excessive abnormal healing.
One of the most devastating sequelae of a burn
injury is the for-mation of hypertrophic
scars. Clinicians cannot reliably predict or prevent the formation of
hypertrophic scars. Hypertrophic scars are more common in children, in people
with dark skin, and in areas of stretch or motion. The pathophysiology behind
these scars is not completely understood, but they are characterized by an
overabundant matrix formation, especially collagen.
Hypertrophic scars and wound contractures are more
likely to occur if the initial burn injury extends below the level of the deep
dermis. Healing of such deep wounds results in the replacement of normal
integument with highly metabolically active tissues that lack the normal
architecture of the skin. In the collagen layer beneath the epithelium, many
fibroblasts proliferate gradually. Myofibroblasts, cells that have the ability
to contract, are also present in immature wounds. As the myofibroblasts
contract, the collagen fibers, which normally lie in flat bundles, tend to form
a wavy pattern. Eventually the collagen bundles take on a super-coiled
appearance and collagen nodules develop. The scar be-comes red (because of its
hypervascular nature), raised, and hard.
personnel must be proactive in the prevention and management of scar formation.
Compression measures are in-stituted early in burn wound treatment. Ace wraps
are used ini-tially to help promote adequate circulation, but they can also be
used as the first form of compression. Scar management occurs mainly in the
rehabilitative phase, after the wounds are closed. Hypertrophic scarring may
cause severe contracture across in-volved joints. Therefore, prevention and
management of this type of scarring is essential (see “Prevention of
Hypertrophic Scarring” in the rehabilitation phase discussion). However, these
scars are limited to the area of injury and gradually regress over time.
large, heaped-up mass of scar tissue, a keloid, may develop and extend beyond
the wound surface. Keloids tend to be found in people with darkly pigmented
skin, tend to grow outside of wound margins, and are likely to recur after
of the wound to heal may result from many factors, in-cluding infection and
inadequate nutrition. A serum albumin level of less than 2 g/dL is usually a
factor in impaired healing in the burn patient.
Contractures are another concern as wounds heal.
The burn wound tissue shortens because of the force exerted by the fi-broblasts
and the flexion of muscles in natural wound healing. An opposing force provided
by splints, traction, and purposeful movement and positioning must be used to
counteract defor-mity in burns affecting joints.