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Updates in Medicine
Plastic surgery
Richard J Bloom and Kirstie MacGill
MJA 2002; 176 (1): 34
Plastic surgery has seen many changes in the past five years.
Advances in our knowledge of genetic coding, growth factors, and
tissue engineering offer the potential for new treatment options
in the near future.
Prevention. Craniofacial surgery has undergone an explosion of
new discoveries over the past five years, which has the potential
to lead to dramatic improvements in diagnosis and treatment of
craniofacial disorders.
Recent studies have demonstrated that mutations in the genes
that code for fibroblastic growth factor receptors (FGF-R) are
at least partially responsible for both syndromic and non-syndromic
craniosynostoses (Figure).1 To date, four FGF-R subtypes have
been identified. These tyrosine kinase transmembrane proteins
function as high-affinity receptors for fibroblast growth factors
and have been implicated in the regulation of cellular proliferation,
differentiation, chemotaxis and apoptosis.
Clinical applications of these findings are currently limited
to genetic testing for some of the common craniosynostosis syndromes,
but the hope is that these conditions will one day be treated
with a combination of minimally invasive procedures and gene therapy.
In a similar way, the complex cascade that determines upper-limb
development is being unravelled. A number of important protein
signals have been discovered and their role in upper-limb growth
may provide therapeutic options in prevention of upper-limb anomalies.
Diagnosis. Malignant melanoma is one of the most common cancers
in Australia, with the estimated risk of developing a melanoma
before the age of 75 years in Australia being one in 26 for men
and one in 36 for women. Management of melanoma saw dramatic changes
through the 1990s, in particular with regard to safe excision
margins. However, it remains an intense area of research. Studies
are now in progress to look at the role of sentinel-node biopsy.
This technique, first described in 1992,2 involves identification
of the first draining lymph node from the primary melanoma site
using a combination of radioactive tracer and patent blue dye.
The technique has already been shown to be a good indicator of
spread of melanoma to draining lymph nodes. This could provide
prognostic information and direct adjuvant therapies, potentially
treating early disease spread. It has the advantage of causing
less morbidity than traditional block dissections. Currently,
sentinel-node biopsy should be considered for any melanoma thicker
than 1 mm, but only in the context of a controlled clinical trial.
Intervention. Chronic and other difficult-to-manage wounds remain
a huge treatment challenge and cost burden to the community. One
of the greatest advances has been the development of low-pressure
dressings.3 These dressings consist of a non-collapsible evacuation
tube connected to a sub-atmospheric pressure system, which is
embedded within medical-grade reticulated polyurethane ether foam
dressing.
This technique removes excess interstitial fluid, increases vascularity,
decreases bacterial colonisation and aids the natural tendency
of the wound to contract. Additionally, it is only changed every
72 hours, thus decreasing labour costs and patient discomfort.
Another area of wound care that is being developed and used by
plastic surgeons is the determination of the precise biochemical
processes that control wound healing. Already, the roles of a
number of growth factors and cytokines have been defined. It is
envisaged that during the 21st century new treatments will be
developed to change cell function in a favourable way with the
addition of positive growth factors and the removal or inhibition
of negative growth factors. Some clinical trials have already
been conducted using platelet-derived growth factor.4 Biochemical
modification of wounds will have implications not only for treating
chronic wounds, but also in preventing or controlling scarring.
Bioresorbable plating systems represent an enormous development,
particularly in the area of craniofacial surgery. Previous systems
consisted of plates and screws made of stainless steel or Vitallium.
Although these materials provide rigid fixation, have excellent
tissue compatibility, and are corrosion resistant, they are permanent
unless surgically removed, and thus carry long term potential
for infection, migration and limitation of growth. Polyglycolic
acid and poly-l-lactic acid fixation systems maintain their strength
long enough to allow healing, and are then broken down completely
by the body, thus eliminating these long term complications.
Tissue engineering is one of the most exciting advances, and
may lead to a new era in medicine: the potential to create new
tissues or induce their regeneration. The basic requirements for
this process are cells, a scaffold for the cells to grow on, and
cellular signals or growth factors, which differentiate and stimulate
cell growth. For the new tissue to be incorporated into the body,
a blood supply then needs to be established. Although plastic
surgeons have been "engineering" tissues for decades,
these new developments raise the possibility of manufacturing
tissues and organs ex vivo. This technology is already used in
the area of burns surgery to create skin replacements when donor
sites are limited by the extent of the injury.
References
Robin NH. Molecular genetic advances in understanding
craniosynostosis. Plast Reconstr Surg 1999; 103: 1060-1070.
Morton DL, Wen DR, Wong JH, et al. Technical details of intraoperative
mapping for early stage melanoma. Arch Surg 1992; 127: 392-399.
Argenta LC, Morykwas MJ. Vacuum-assisted closure: a new method
for wound control and treatment: clinical experience. Ann Plast
Surg 1997; 38: 563-576.
Steed DL. Clinical evaluation of recombinant human platelet derived
growth factor for the treatment of lower extremity diabetic ulcers:
Diabetic Ulcer Study Group. J Vasc Surg 1995; 21: 71-78.
(Received 4 Dec 2001, accepted 4 Dec 2001)
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