Equis ISSN 2398-2977

Skin: grafting - techniques

Contributor(s): Steve Adair, Stephen Adams, Larry Booth, Rachel Murray, Patrick Pollock, Chris Whitton

Introduction

  • Although large skin defects on the neck and trunk can have a good cosmetic and functional outcome through healing by contraction and epithlialization, large defects on the limbs, parts of the head and near body orifices can result in reduced function and a poor cosmetic outcome.
  • Large full thickness skin defects as a result of trauma or surgery may exceed the capacity of normal repair mechanisms.
  • Large wounds may take a long time to repair by normal epithelialization and contraction.

Graft types

  • Pedicle graft:
    • See conjunctival pedicle grafts   Conjunctiva: graft - pedicle flap  .
    • Graft remains connected to the donor site by a pedicle which contains blood supply.
    • Excellent cosmetic outcome.
    • Use: eyelid injuries, multiple sites following skin expansion techniques, eg ballon stretching.
    • Vascular pedicle grafts not commonly used in horses.
  • Free graft:
    • Isolated piece of skin.
    • Island or sheets.
    • Full-thickness or split-thickness.
    • Applied to skin as solid or meshed sheets.
    • Implanted in granulation tissue as pinch grafts, punch grafts or tunnel grafts.
  • Autografting:
    • Same animal as donor and recipient.
    • No detrimental immune response.
    • Most commonly used.
  • Allografting:
    • Transplant between horses.
    • Grafts survive for a few weeks then become rejected and disappear.
    • Use - test receptivity of wound to donor skin before autographting.
  • Xenografting:
    • Transplant from another species to the horse.
    • Use biologic dressing to reduce bacterial colonization, prevent exuberant granulation tissue   Wound: granulation 04 - excessive  and stimulate angiogenesis and epithelization   Carpus: wound 02 - epithelialization  .

techniques

  • Island grafting:
    • Pinch (seed).
    • Punch.
    • Tunnel (strip).
  • Sheet grafts:
    • Mesh.
    • Split-thickness.
    • Full-thickness.

Uses

  • Insufficient skin to permit primary or secondary closure.
  • Large wounds in which healing by second intention   Wound: healing - second intention  will be prolonged and result in a large scar.
  • Wounds where excessive granulation tissue formation prevents contraction.
  • Wounds where healing by second intention could result in contracture that decreases function, eg near an orifice, joint or eye.

Advantages

Island grafts

Pinch (seed) grafts

  • No general anesthesia required.
  • Easy technique.
  • Relatively mobile recipient site.

Punch grafts

  • As above.
  • Hair and glands transplanted   →   better cosmesis.

Tunnel (strip) grafts

  • As above.
  • Better cosmesis.

Sheet grafts

Mesh grafts

  • Flexible graft.
  • Permits drainage.
  • Mobile.
  • Increased opportunities for wound healing due to multiple epithelial edges.
  • Reduced wound contraction.
  • Can graft over all tissue except bone devoid of periosteum and tendon devoid of paratenon.

Split-thickness grafts

  • Better 'take' than full-thickness.
  • Minimal loss of cosmetic effect at donor site.
  • Can graft over all tissue except bone devoid of periosteum and tendon devoid of paratenon.

Full-thickness grafts

  • Good cosmetic result.
  • Little wound contraction.
  • Can graft over all tissue except bone devoid of periosteum and tendon devoid of paratenon.

Disadvantages

Island grafts

Pinch (seed) grafts

  • Poor cosmesis (cobblestone appearance).
  • Poor quality healing   →   susceptible to breakdown with excessive movement.
  • Require the presence of granulation tissue.

Punch grafts

  • General anesthesia may be necessary.
  • May have poor cosmetic result if hair growth from graft is rarely aligned in same direction.
  • Require the presence of granulation tissue.

Tunnel (strip) grafts

  • Poorer cosmesis than mesh grafts.
  • Require the presence of granulation tissue.

Sheet grafts

Mesh grafts

  • General anesthesia may be necessary.
  • Expense of dermatome.
  • Poor cosmesis in the short-term.

Split-thickness grafts

  • General anesthesia may be necessary.
  • Expense of dermatome.
  • Fewer hair follicles and glands.

Full-thickness grafts

  • General anesthesia   Anesthesia: general - overview  may be necessary.
  • Cannot be applied to large defects.
  • Does not 'take' as well as split-thickness graft, due to shearing forces between graft and recipient bed.

Requirements

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Procedure

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Aftercare

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Outcomes

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Further Reading

Publications

Refereed papers

  • Recent references from PubMed and VetMedResource.
  • Bristol D G (2005) Skin grafts and skin flaps in the horse. Vet Clin Equine 21, 125-144 PubMed.

Other sources of information

  • Schumacher J (2006)Skin Grafting.In:Equine Surgery. 3rd edn. Ed: Auer J A & Stick J. W B Saunders, Philadelphia. pp 269-287.
  • Knottenbelt D C (2003)Handbook of Equine Wound Management.Saunders; Elsevier Science Ltd. ISBN-10: 070202693X; ISBN-13: 978-0702026935.


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