BURN SCAR AND IT’S COMPLICATIONS
first 6 days, wound inflammation has begun and the various
components of healing have been initiated. In superficial
burns, epidermal regeneration will be relatively rapid, if
the wound environment is optimized. The injured dermal
elements are usually covered by new epithelium within 2
weeks. The hyperplasia of dermal fibroblasts then begins to
resolve, and healing is complete with only modest amounts of
collagen deposited. The wound usually becomes relative
pliable with time and minimal wound contraction is seen.
Cosmetically, the superficial second degree burn, which
heals in 2 weeks, results in minimal to no long-term
healing takes 3 weeks as would be the case with a mid-dermal
burn, scar is likely to be minimal except in higher risk
groups, e.g. dark skin.
Post burn scar relative to re-epithelialization
- Healing in 2 weeks –
minimal to no scar
- Healing in 3 weeks –
minimal to no scar except in high risk scar
Healing in 4 weeks or more – hypertrophic in
more than 50% of patients
Post burn scar relative to skin graft
- Early grafting leads
to less scar
- The thicker the skin
graft, the less the scar
- Sheet grafts have less
scar then meshed grafts
- The wider the mesh,
the more the scar
Scar will develop at the edges of a graft in
high risk scar formers (dark skinned)
of Burn Scar
biochemistry of the wound changes dramatically if it has not
closed by 3 weeks or longer as would be the case of a
healing deeper burn or a deep skin graft donor site.
of the inflammatory phase, in an open or infected burn,
increases the concentration of growth factors known to
produce increased fibroblast numbers and excess amounts of
collagen and extracellular matrix.
cells leads to increased release of histamine. Histamine is
known to stimulate growth of fibrous tissue.
Scar shows an
increase in the thickness of the new epithelial layer but
without rete pegs, making the surface vulnerable to injury.
The keratinocytes becomes a factory for fibrotic growth
factors. In addition, an excess and prolonged
neovascularization is found in both types of scar compared
to normal scar. Fibroblasts are also found in increased
numbers, leading to increased collagen deposition as well as
more matrix. These fibro-blasts are more sensitive to
growth factors than normal skin fibroblasts. The released
chondroitin develops sulfated side chains, which lead to a
more rigid scar. Increased and persistent levels of
chondroitin sulfate are present, located in the modular
areas of excess collagen. This is characterized by
increased water content, which increases scar firmness. A
decrease in interferons, cytokines that downregulate
collagen and matrix synthesis is also noted. This
abnormality leads to less collagenolysis and matrix
degradation with remodeling.
The status of
the wound bed will dictate the degree of surface
inflammation. Increased surface and matrix metalloproteases
oxidants and other mediators of inflammation result in a
continued breakdown of new tissue and stimulate fibroplasia.
Causes of Excess Wound Inflammation
- Chronic open Wound
- Surface necrosis of
Infection, increased bacterial burden
Hypertrophic scar is an
aberration of the normal healing process.
scar occurs only in humans, making the study of pathogenesis
and treatment more difficult. It occurs in males and
females, being more common in the teenager or younger adult.
scarring is seen in more than 50% of healed deep burns as
characteristics of proliferative or hypertrophic scar are
shown in the list below. Proliferative scar is
characteristically red, raised, rigid and painful. Itching
is also universally present.
Characteristics of Hypertrophic Burn
- Surface erythema
- Raised from wound
- Lack of elasticity
- Increased collagen
- Painful and itchy
The increased scar is particularly prominent
around joints, where tension is more common.
Hypertrophic Burn Scar
deposition in the re-epithelialized wound results in a
raised, hyper-pruritic wound that produces functional
impairment due to rigidity and pain as well as a severe
cosmetic abnormality. Severe discomfort results. Pain with
any scar movement retards activity and continued itching
leads to scratching and skin breakdown. Superficial
infection of the skin breakdown can then result. The scar
often splits with exercise, especially if it becomes dry.
Grafted wounds develop much less hypertrophic scarring than
the deep dermal burn that heals spontaneously. Both the
contracture and hypertrophic scarring process peak between 3
and 6 months after injury, frequently long after the patient
has been discharged.
formation and hypertrophic scarring peak 3 to 6 months after
injury and partially resolve at 12 to 18 months.
It is crucial
that the care providers recognize the delayed onset so that
precautionary measures can be taken. The hypertrophic scar
begins to decrease with time as collagen lysis begins to
exceed the rate of deposition. The latter begins to
decrease as the inflammatory process diminishes. Between 12
and 18 months, a softening and flattening of the scar can be
seen along with a loss of scar hyperemia. The presence of a
hyperemia indicates that active scar turnover is still
present. The lack of hyperemia is a good sign that the scar
is now mature and will remain in its present state, although
the scar may relax. The underlying tissues can be
Causes of Proliferative Burn Scar
- Tension on the wound
- Excess inflammation in
- Inflammatory stimulus
- Wound open for more
than 3 weeks
- Lack of dermal
a variety of methods to control and decrease scar
formation, and in most patients, more than one approach
is used. However, the assessment of the response of the
scar process to the approach used is problematic as an
accurate method for the objective quantitative
assessment of scar remains to be developed.
scar is the sum of the response to injury repair,
and intervention, the scar is not a static process,
but rather a dynamic one changing over time,
especially during the first 18 months or until
healing is complete.
Subjective assessment includes various factors that
contribute to the patient’s own evaluation (visual
and tactile contributions), which includes both
perception and attitude (body image). Objective
assessment includes the physical characteristics of
size, shape, volume, color, texture, and
probability. In addition, structural, mechanical
and physiologic characteristics are included. The
Vancouver Scar Scale is a commonly used method that
attempts to quantify most of these parameters.
Despite an attempt at objectivity, all objective
markers are very much dependent on the examiner’s
expertise and perceptions, and assessment will vary
considerably between different examiners.
approaches currently being tested include
two-dimensional and three-dimensional imaging
techniques and computer vision algorithms. A range
scanner is a device that allows acquisition of 3-D
data and can accurately estimate scar volume. This
approach can also be used to assess pliability.
and itching are also assessed and documented
usually using the 0-10 scale
Hypertrophic Scar on Donor Site
Delayed healing of donor site led to scar
Red and Raised
Maturing Scar (12 months)
Note scar is less red
Early Scar Formation (2 months)
Hand burn which
healed in just over 3 weeks
Note beginning of red raised scar
of Hypertrophic Scar
Prevention is best achieved by early wound closure.
Skin grafting should be the approach to a burn expected to take more than 3 weeks (high risk scar
formers or 4 weeks to re-epithelialize. Temporary skin substitutes may be of benefit for decreasing
scar in the partial thickness wound by increasing healing rate while protecting the wound. Permanent
skin substitutes with a dermal component may be advantageous in the full thickness wound.
Temporary skin substitutes
Permanent skin substitutes
has been well established that a dermis containing
active dermal elements is critical for the
orchestration of a normal healing process, and the
absence of dermal elements will lead to excess
scar. The role of the dermis can be divided into
its structural component and its biological
scaffolding or structure of the matrix, mainly
collagen type I, is made up of the collagen fibres.
The collagen lattice provides contact orientation
for dividing and migrating cells (30-35). This
cell-guidance system allows for a more organized,
less abundant scar. Providing a collagen lattice
onto the wound surface prior to scar formation
allows for the ingrowth of a new matrix over time.
The matrix orchestration system is composed of
dermal proteins like fibronectin and growth factors,
Hyaluronic acid, a complex carbohydrate and the
partial-thickness or full-thickness burn no longer
has these key dermal elements. However, there are a
number of collagen-matrix products now available
which are designed to restore some of the
dermal-like properties when placed on a clean
full-thickness wound bed. The addition of these
dermal-like properties should allow for a more
normal healing process, thereby potentially
decreasing scar. Providing a dermal-like layer to a
full-thickness wound especially a wound, which is
closing by secondary intent, should help to control
scarring in cutaneous wounds, especially if the
components maintain the biological activity of
normal dermal elements. Several studies have
demonstrated decreased scarring using some of the
more novel matrix dressings
F. Treatment of Hypertrophic Scar
Excision is only feasible for a small
scar. A simple excision of either an established
hypertrophic scar or keloid has a very high
recurrence rate (over 50%). The exception for
hypertrophic scar appears to be tension-releasing
procedures, e.g. z-plasties to release burn
contractures of burn scar removal with tension-free
closure where results are much better. Keloid
recurrence also remains a major problem, although
the addition of corticosteroids to the edges of the
excision decreases recurrence. Therefore, surgical
approaches to late scar need to be combined with
Laser Surgery. This promising approach
to both hypertrophic scar and keloids uses a laser
beam to cause a thermal tissue reaction, which can
heat the injury or coagulate specific tissues. The
CO2 and argon lasers are ineffective.
However, the newer flash lamp-pumped pulse dye laser
selectively decreases scar blood flow with a
demonstrated improvement of more than 50% in over
50% of cases. A more pliable, less pruritic, and
less erythematous scar results.
Cryotherapy. Comparable to laser
therapy, cryotherapy results in microcirculatory
disturbances leading to tissue damage, especially
fibroblasts. Positive response is seen in 50% to
70% of patients, which is comparable to laser
therapy. Treating early hypertrophic scars has the
Typically, these surgical approaches are combined
with other modalities, such as corticosteroids and
other pharmacologic approaches and biophysical
therapies like pressure, to optimize results.
The biophysical basis for therapeutic efficacy in
scar management remains controversial, especially
the relevance of abnormal biochemical pathways, and
their pharmacologic modifications. However, these
approaches have become the standard of care for
hypertrophic scar control – both prevention and
treatment. Keloids in general respond minimally to
use of fitted elastic garments to generate about 24
mm Hg on the hypertrophic scar was popularized more
than 20 years ago, especially for burn scar.
Pressure, if used 18-24 hours a day for at least 6
months, appears to have at least partial success in
producing a thinner, more mature, and more pliable
scar in over 50% of patients. The garments should
be used as soon as the wound is closed. The
pressure decreases scar blood flow, decreasing
protein deposition, increasing lysis, decreasing
edema and chondroitin sulfate. However, it is clear
that the initial measured pressure lasts only for a
very short time as tissue edema decreases, lessening
the pressure. Yet a positive effect may persist.
Recent theories include an increase in scar tissue
temperature due to the tight garment weave.
Increased temperature, even by 1°C, will
significantly increase collagenolysis and scar
maturation, thus the use of heating as a treatment
- ultrasonic, microwave heating
- gel sheeting
- scar massage
- protein kinase C inhibitors
Measurements for Pressure Garments
Careful fitting is done to obtain
Fitted Pressure Garment
To be worn 23 out of 24 hours a day
or microwave heating
soften scar and loosen still-stiff joints, ultrasonic or
microwave heating decreases the tensile strength of a
scar, and appears to reduce collagen content possibly by
increasing collagenase activity; some benefit is seen in
at least half the patients.
Form-fitted silicone gel sheets held in place by
elastics and worn at least 28 hours a day for
several months also appear to increase scar
maturation and decrease hypertrophy. Although the
mechanism was initially thought to be due to
pressure or increased temperature, neither appears
to occur. Silicone itself is not playing a role has
the same results occur with the use of a hydrogel.
Current evidence suggests that maintaining scar
hydration is the common element, although the effect
of hydration jon decreasing scar is unclear.
However, the fitted sheet also takes tension off the
wound, a known stimulant of scar. Early use has the
approach is usually combined with several other
modalities. Deep massage reportedly stretches fresh
scar and breaks down the cement or matrix holding
the scar contracted. Massage therapy appears most
beneficial in preventing contractures. However,
massage also mechanically stimulates fibroblast
synthesis of collagen. Therefore, this approach
must be combined with an anticollagen synthesis
approach to be of significant benefit.
Nonsteroidal anti-inflammatory agents have been
shown to decrease fibrosis through inhibition of
Il-1 and prostanoids, known to stimulate fibrosis.
However, data verifying clinical efficacy in
controlling excess scar are lacking.
have been shown to be effective not only in
controlling pruritus, but also suppressing
histamine-induced tissue proliferatives. Topical
agents such as doxepin cream would likely be more
effective as the concentration in the scar would be
greater. In addition, doxepin (Prudoxin) is 800
times more potent than diphenhydramine as an
newer antiallergic drugs also inhibit the release of
histamine and prostanoids from wound mast cells.
These agents, except for some mild sedation, are
very safe. Corticosteroids are, of course, used to
control hypertrophic scar and keloids by injection
into the scar itself. However, the corticosteroids,
except for stabilizing mast cells, are not acting as
an anti-inflammatory agent, but rather by inhibiting
are the main agent in the protein synthesis inhibitors
category. These agents, when injected into scar,
decrease fibroblast proliferation, decrease
angiogenesis, and inhibit collagen synthesis and also
extracellular matrix protein synthesis. Complications
include pain on injection, thinning of surrounding skin
if the steroid spreads to normal tissue, systemic
absorption, and recurrence of scar at a later date.
are known to reduce the production of major scar forming
growth factor TGF-ß. Both intravenous and intralesion
injections of interferon have shown significant clinical
benefits on reducing hypertrophic scar and keloid.
Popularity to date is hampered by high cost and
unfamiliarity with this approach. Agents that inhibit
collagen cross-linking would decrease scar rigidity and
collagen deposition. The most promising agent in this
category is topical putrescine, which has been reported
to decrease hypertrophic scars with no side effects.
Stimulation of Proteolytic enzyme synthesis works by
increasing the degradation rate of collagen and matrix
proteins. Calmodulin and protein kinase C inhibitors
have been shown to be somewhat effective, but further
data are needed. Calcium channel blockers inhibit the
incorporation of protein into extracellular matrix
protein. Several studies have reported an increased
rate of scar degradation.
Hypertrophic scar can lead to wound contracture if the scar
crosses a joint. Contracture is the result of shortening of
the hypertrophic scar with time.
contraction develops. This is produced the contractile
myofibroblasts and the deposition of ground substance and
collagen-end result is a shortened noncompliant wound that,
if it crosses a joint, will result in contracture. The most
common contractures are essentially identical to the most
common position abnormalities produced with inadequate
and Passive Exercise
Splinting to maintain position of
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