Adverse
scar
There are many types of adverse scar (Table
3.3), many of which can be avoided or prevented by correct incision planning
and adequate wound management. Some types, however, cannot be prevented and
are unpredictable in their occurrence. The appearance of some scars can be
improved by surgical or other means, but scars can never be removed totally. The
types of adverse scar will be discussed and suggestions for avoidance or
management made.
Incisions that pass along ideal lines are more likely to leave acceptable scars. There are many types of ‘lines of election’ for incisions, most of which pass along skin wrinkles or along relaxed skin tension lines (that is a line along which maximal skin tension passes when the part is in a relaxed position). These lines have minimal tension across the wound edges. A scar which crosses these lines will have a greater tendency to stretch or become hypertrophic, and even if not hypertrophic will usually appear more conspicuous than one which follows a relaxed skin tension line. Other ideal positions for scars are at junctions between anatomical areas such as the nose and the cheek, the cheek and the ear or the junction between a hairy and hairless area
Poor alignment
of features
Where a scar crosses the junction between
distinct anatomical features, such as the vermillion of the lip, it is
essential that these features are accurately realigned. Such misalignments result in conspicuous adverse scars.
Stretched scar
Scars from excisional wounds on the trunk and
limbs often stretch. It has been shown that the width of a scar depends on the
tension across the wound at the time of wound closure. In general, steps to
avoid excessive tension across the wound will be rewarded with narrower scars.
Where tension cannot be avoided there is evidence that prolonged wound support
with buried nonabsorbable or long-term absorbable sutures can minimise scar
stretching.
The process of wound contraction continues in
the remodeling phase of scar maturation such that a scar will always be
shorter than the incision from which it results. Where a linear scar crosses a
flexor surface this shortening may result in a scar contracture which may
prevent full extension of that part. This will occur on the flexor surface of a
finger if a straight-line incision is used. Curved or zigzag incisions will
avoid this problem. Where scarring is extensive such as burn scars then scar
contractures may be inevitable. Linear scar contractures can be corrected by
realignment of the scar; there are various techniques to do this including Z-plasty
and multiple Y—Vplasty. More extensive contractures will require release and
introduction of additional skin by means of grafts or flaps.
Pigment
alteration
The new epidermis of a scar will often not
have the same degree of pigmentation as surrounding unscarred areas. Most scars
are hypopigmented, but hyperpigmentation can also occur. The only ways to deal
with this problem are cosmetic camouflage or tattooing. -
Contour
deformity
Where wound edges are not anatomically aligned
in the vertical plane or where a bevelled cut is not repaired accurately there
is a risk of contour irregularity in the healed scar. This can usually be
avoided by accurate wound repair, if necessary excising bevelled edges to
restore even vertical edges for repair. A variation of this problem occurs when
a curved laceration heals, in that the scar shortens and that portion of skin
within the concavity of the curved scar tends to become raised. This problem is
known as trapdooring or mushrooming. It will often improve with time, but scar
revision is sometimes indicated to correct it.
In traumatic wounds it is possible for
particles of grit, dirt or soot to become implanted in the wound as it heals.
This
Stitch marks
If skin sutures are left in place for more
than 7 days then scars from the stitch marks will usually result. This problem
can be avoided by using subcuticular sutures wherever possible, removing skin
sutures before 7 days and, where prolonged wound support is needed,
supplementing skin sutures with subcuticular sutures allowing early removal of
the skin sutures. Adverse scars due to prominent stitch marks can rarely be
improved by scar revision.
Hypertrophic
scars
The risk of developing a hypertrophic scar can
be minimised by ensuring quiet primary healing. Where hypertrophy does occur
patience is usually rewarded by improvement with time. Massage of the scar with
moisturising cream or the application of pressure to the remodelling scar can
accelerate the natural process of maturation. Patients with hypertrophic bum
scars are supplied with custom made Lycra pressure garments that promote
acceleration of scar maturation. Revision of hypertrophic scars is appropriate
where they cross skin tension lines or where a specific wound healing
complication occurred. In the absence of these factors scar revision should be
avoided as it will usually be met with recurrence.
In some situations there is an extreme
overgrowth of scar tissue that grows beyond the limits of the original wound and
shows no tendency to resolve. Keloid scars are biologically identical to
hypertrophic scars that fn turn are an extension of normal scar behaviour.
Whilst it is usually possible to make the distinction between these scar types,
they are best regarded as a spectrum of scar behaviour (Table
3.4). Keloid scars
are more frequent in Afro-Caribbean and oriental racial groups (Fig. 3.15).
They often occur in wounds that healed perfectly