Skin grafts

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Skin grafts

• MS3 Lecture Series
• Christian El Amm, MD
• University of Oklahoma

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Historical perspective

• First used 2500-3000 BC, (Hindu Tilemaker Caste )
• Re-discovered in 19th century, pinch grafts then
  sheet grafts
• Now mainstay of burn therapy and cuticle
  reconstruction
• Hair grafts, melanocyte transplants specialized
  transfers
• Cultured skin

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Layers of skin Split thickness
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Thickness

• Thin STSG 0.008-0.012 inches mostly epithelium,
  thin reticular (elastin)
• Medium STSG 0.012-0.018 in most commonly used
• Thick STSG 0.018-0.030 in. almost like full
  thickness, used in certain application like face,
  flexion surfaces where contraction is minimal

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Full Thickness FTSG
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Technique
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Dermatomes
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Mesher
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Technique
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Donor Site areas
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Donor site appearance
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Donor site care

• Several techniques
• Occlusive dressing
• Semi Occlusive Dressing
• Absorbent gauze
• Most Common tegaderm 3M, semi occlusive water
  vapor permeable, oxygen permeable

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healing
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Healing
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healing
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Donor site healing

• Basal cell layers in epidermal appendages
  de-differentiate into basaloid morphology
• Migrate into defect by diapedesis until contact
  inhibition
• Contact signal beginning re-differentiation into
  Stratified Corneal Epithelium layers.

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Physiology

• 1st 24-48 hours plasmatic imbibition
• Nutrients and oxygen infiltrate through
  capillaries lt1mm away (thus the limitation on
  thickness)
• Fibrin bridges created IMPORTANCE OF COMPRESSIVE
  DRESSING

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Physiology

• 36-48 hours later Inosculation
• Capillary buds sprout through the skin graft and
  connect to pre-existing vascular channels and
  create new one
• Collagen bridges created

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Physiology

• Neurotization nerve buds from the bed grow into
  the graft.
• Sensation type (Vibration/fine touch etc) is
  that of the bed (e.g. pulp) (Endings???)
• Two point discrimination always less than normal
• Sweat glands, erector pilae ???

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Indications

• Well vascularized, non infected bed
• Large coverage defect not amenable to direct
  closure or local flap coverage

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Contra-indications

• Relative flexion areas, constant shear and
  friction
• Non vascularized bed, cancer, infection

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Complications

• Failure, or non-take
• Hyperpigmentation (Thin STSG), Hypopigmentation
  (Thick STSG)
• Contraction
• Meshed appearance
• Dryness, scaling etc

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Contraction and Contracture

• Primary contraction due to elastin fibers in
  dermis. More pronounced in FTSG. Corrected by
  stretching the graft
• Secondary contraction, or contracture, more
  severe in thinner STSG, more severe if meshed.
  May reach 40 of surface. Correction Prolonged
  splinting

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Meshed grafts

• Most common
• Less cosmetic result
• More contracture
• Better take (allows egress of fluids)
• Covers wider surface and irregularities.

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Other types of grafts

• Autograft
• Allograft
• Xenograft
• Hair, melanocyte, fat grafts
• Composite graft skincartilage

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Current trends

• Cultured Epithelial Autografts A 1 sq cm piece
  of skin is cultured in-vitro for keratinocyte
  expansion, delivered onto sheets, and given 17-21
  days later to cover nearly 90 burn
• Dermis replacement Hyaff (hyaluronic scaffold
  with cultured dermal fibroblasts), Alloderm
  donor cadaver decellularized dermis, Integra etc