Split-Thickness Skin Graft (STSG)

For more images and videos of techinque of harvest, care of donor site: Case Example Split Thickness Skin Graft STSG Zimmer Dermatome

see also: Skin Graft Donor Site Care
return to: Reconstructive Procedures Protocols

1. General Considerations
   1. Indications
      1. Reconstruction of a skin defect
      2. Reconstruction of non-skin epithelial defect
         1. Intra-oral
         2. Sinus (as after maxillectomy)
         3. Laryngeal defect or urethral stricture (see better alternative: Buccal mucosal graft)
   2. Alternatives-
      1. Consider 'reconstructive ladder': healing by secondary intention/primary closure/flap reconstruction/distal flap
      2. Cadaveric allografts
      3. Processed collagen: Alloderm
      4. Integra
      5. Porcine xenograft
   3. Pertinent anatomy/ physiology
      1. Skin anatomy
         1. A STSG consists of the epidermis and part of the dermis (see Full thickness skin graft: consists of epidermis and entire dermis)
         2. The reticular layer of dermis contains epidermal appendages (sebaceous glands, sweat glands, hair follicles), which are lined with epithelial cells that have the potential for division and differentiation
         3. These structures are critical for skin graft healing. Injuries to these structures (eg. Cauterization, Accutane treatment) increase the risk of poor healing
      2. Phases of skin-graft survival
         1. Imbibition- graft absorbs (imbibe) nutrients from underlying recipient bed
         2. Inosculation- blood vessels in skin graft grow to meet the vessels (inosculate = kiss) of the recipient bed
         3. Neovascularization- new blood vessels from between the graft and recipient tissues
      3. STSG vs. full thickness skin grafts (FTSG)
         1. STSG- better survival but more contraction and potential pigmentation change. Donor site heals through re-epithelialization, which can cause discomfort.
         2. FTSG- higher metabolic needs of thicker graft causes higher rates of flap failure, but are a better color match and contract less. Donor site is usually closed primarily.
   4. Donor site considerations
      1. Any part of the body may be used, but an area that can be hidden by clothing and minimize discomfort is usually chosen.
      2. Posterolateral thigh is a common site as it provides a large, relatively flat surface area for harvest
      3. Scalp
      4. Free flap- especially useful if the flap is placed intraorally or subcutaneously, de-epithelializing the skin paddle eliminates donor site pain because the flap skin is insensate
2. Equipment
   1. Dermatome (eg. Zimmer ) with blade and blade guards
      1. Alternatively, the harvest may be performed freehand using a scalpel
   2. Vasocontrictive or thrombotic agent – eg. thrombin, epinephrine
   3. #15 scalpel
   4. Tongue depressor, or other straight, rigid instrument
   5. Mineral oil
3. Procedure
   1. The dermatome is fitted with the appropriate width blade guard for the desired size of skin graft. The thickness is typically set to 0.015 - .018 inches (accommodates the width of a #15 blade) for an intermediate-thickness STSG.
      1. Mineral oil may be applied to the blade to facilitate lifting the graft off the blade later
   2. Adequate local/regional or general anesthesia is given.
   3. The donor site is cleaned and any residual prep solution is wiped off to allow the dermatome to glide over the skin smoothly.
      1. Lubricating the skin with mineral oil also helps
   4. Turn the dermatome on, then holding it at approximately 30 degree angle to the skin surface, engage the skin with a gentle downward pressure and advance the dermatome forward in a steady, continuous motion. Various techniques can be employed to provide traction on the skin and facilitate smooth advancement:
      1. The surgeon pulls back on the skin behind the dermatome while an assistant flattens and provides countertraction in front of the dermatome using a tongue depressor, metal ruler, or other straight, rigid instrument
      2. An assistant may alternatively grasp the skin just beyond the borders of the graft using towel clamps, pulling in opposite directions to stretch the skin
   5. When the appropriate length is reached, harvest is terminated.
      1. The dermatome can be tilted up and then lifted off the skin to cut the distal edge of the graft
      2. The dermatome can be stopped while still in contact with the skin, and the final edge is cut using a scalpel
   6. The graft is placed in saline until use
   7. Gauze/Telfa soaked with a vasocontrictive/thrombotic agent (eg. thrombin, epinephrine) is applied to the donor site
      1. Do not do this if the graft is harvested from free flap skin, to avoid possible vascular compromise
   8. The STSG may be meshed before inset, or “pie-crusted” after inset to allow fluid to escape rather than accumulate below the graft as a hematoma/seroma
   9. Care should be taken when placing the graft to place it with the dermal side, typically shinier and whiter, down and so there is neither excessive stretching or wrinkling
   10. The STSG is usually secured to the recipient site by using 4 corner sutures, then a running suture around the periphery, both with chromic gut. 4-0 chromic on RB-1 needle is ideal.   
       1. Additional tacking sutures may be placed within the graft to increase adherence  to the underlying tissue
4. Post-operative care
   1. Post-op care regimen varies based on surgeon preference
   2. The graft dressing should provide uniform pressure to prevent shearing of the graft and prevent hematoma/seroma formation
      1. Wound-vac, if it can be contoured to hold suction on the wound, is useful
      2. The dressing is usually removed after 7 days, graft take assessed, and additional dressing selected accordingly (eg. Bacitracin, wet-to-dry)
   3. Donor site dressing options include open, semiopen, occlusive, semiocclusive, and biological (eg. Tegaderm, stapled Allevyn)
      1. See Skin Graft Donor Site Care  protocol
      2. Potential complications: donor site pain, fluid loss, hypertrophic scarring, undesirable pigmentation, prolonged healing
5. References
   1. Akan M, Yildirim S, Misirlioğlu A, Ulusoy G, Aköz T, Avci G. An alternative method to minimize pain in the split-thickness skin graft donor site. Plast Reconstr Surg. 2003 Jun;111(7):2243-9.
   2. Kim PD, Fleck T, Heffelfinger R, Blackwell KE.Avoiding secondary skin graft donor site morbidity in the fibula free flap harvest.Arch Otolaryngol Head Neck Surg. 2008 Dec;134(12):1324-7.

   3. Hoffman HT, LaRouere M.  A Simple Bolster Technique for Skin Grafting.  Laryngoscope, 99(5):558-59, 1989.