When To Use Skin Grafts And What Type To Use

Skin grafting use has exploded, especially when it comes to the new products available. However, with so many products available, it is difficult to know which one to use and when. Sometimes, the question isn’t necessarily if one can use a graft for a wound can receive a graft but rather, should one use a graft for the wound? Larger wounds typically require grafting because if one allows them to heal spontaneously, there are negative effects that one might encounter. Such effects arise from the lack of skin appendages (sweat glands, etc.) and the wound heals by contraction and reepithelialization from the wound edges.¹ However, these wounds end up being less stable and durable in the long run. Therefore, small wounds and large wounds in which the contraction process will not distort critical anatomy or cause any loss in function (i.e. joint contracture) are not necessarily amenable to skin grafting.¹ Burn victims and those with traumatic injuries can receive skin grafts. The risk of failure has always been considered high in chronic wounds but a split thickness skin graft (STSG) may actually be an effective method of treatment.² Split thickness skin grafts are available in thin, intermediate and thick varieties.^1,3 o Thin grafts measure between 0.008 to 0.012 in². o Intermediate grafts measure between 0.013 to 0.016 in². o Thick grafts measure between 0.017 to 0.02 in². o STSGs contain less dermis than full thickness skin grafts and are therefore thinner. o STSGs have a more natural wound healing process. o STSG have less metabolic demand than full thickness skin grafts o STSGs are more likely than full-thickness skin grafts to succeed on a vascularly compromised wound. Note that the thinner the graft, the more likely it is for it to “take” but the less durable it is, the greater amount of contraction occurs. Do not apply STSGs over tendons, cartilage or bone because these structures are technically avascular and will not provide the graft with the blood supply that is necessary during the healing process.³ A STSG can expand as much as eight times its original size. In regard to full thickness skin grafts, harvesting of the graft begins by drawing the outline of the incisions on the skin.³ The typical skin incision is in the form of an ellipse that has a 3:1 ratio of length to width. This allows one to close the donor site without tension. Full thickness grafts are very thick grafts with a higher failure rate than STSGs. Full thickness grafts are more durable than STSGs, can carry hair follicles and there is very little wound contraction with these grafts. Full thickness grafts also retain more of their natural pigmentation and a larger amount of sensation. The most common sites to harvest for full thickness grafts in order of cosmesis are buttock, thigh, abdomen, back, scalp, chest wall and arms.³ Full thickness grafts do not require donor site closure and are typically allowed to heal by reepithelialization.

A Quick Primer On The Phases Of Skin Graft Healing

Skin grafts heal by specific phases of plasmatic, inosculation and reinnervation/reorganization.^1,3 Plasmatic imbibition. Initially, the skin graft survives on the local blood supply within the wound bed by the formation of a fibrin layer. This lasts about 48 hours. Inosculation. New blood vessels sprout in the wound bed and begin to grow and connect into the graft. Reinnervation/reorganization. This may occur for up to two years.² During these processes, fibrin and collagen are aiding in the bonding of the graft to the underlying wound bed. In about seven days from the initial surgery, the skin graft is usually adherent to the underlying wound bed. While the graft continues to heal, the main goals of the dressings are to keep the area moist and maintain an antimicrobial environment. References 1. Coughlin MJ, Mann RA, Saltzman CL (eds.) In Surgery of the Foot and Ankle, eighth edition, volume 2. Mosby, St. Louis. 2. Rose JF, Giovinco N, Mills JL, et al. Split-thickness skin grafting the high risk diabetic foot. J Vasc Surg. 2014;59(6):1657-63 3. McGlamry ED, Banks AS, Downey MS. Foot and Ankle Surgery, third edition, volume 2. Lippincott, Williams and Wilkins, Philadelphia, 2001.