Preparation for a Successful Skin Grafting

Abstract

In this chapter, we shall look into the pre-requisites for a successful skin grafting. This includes patient selection, identifying various factors—patient related, environment related, treatment related, and optimizing them for a successful outcome. Avoiding/removing the adverse factors and improving the wound bed environment require knowledge, experience, and checklist to be followed, so as not to miss any of these pre-requisites. This would ensure complete take of the skin graft, with good reconstructive and esthetic outcome. Various factors include patients\' general health, comorbidities, etiology of wound, duration and contamination, granulation tissue, local wound blood supply, wound sepsis, edema, vascular disease, wound bacteriology culture sensitivity, etc. The ultimate goal of improving success of skin grafting will lead to early recovery of patient, reducing hospital stay, burden on health infrastructure, and reduced loss of workdays, thereby reducing the socioeconomic impact of wound.

1. Introduction

Several factors have to be considered before planning a skin grafting. This ensures achievement of optimal tissue environment at the wound site. The quality of wound bed has to be enhanced so as to ensure a successful “take” of the skin graft. The donor site area skin color, thickness, and mechanical property should preferably match the recipient site skin quality. The causes of poor skin graft include multiple factors such as chronic or insufficiently debrided wounds, poorly vascularized wound bed, or high bacterial load.

2. Recipient site considerations

2.1 Wound bed preparation

Wound bed preparation is a valuable concept that attempts to systematize the approach to the treatment of chronic wounds [1]. The “take” of skin graft depends on a healthy well-vascularized wound bed. It is supported by an adequate quantity of blood vessels near the surface. Appropriate skin graft take is not allowed in ischemic, previously irradiated and scar tissues, bone, and tendon, as they have an insufficient blood supply.

Consistency of necrotic tissue also varies as tissue damage worsens/deepens:

• Slough: yellow/tan, thin, mucinous, or stringy (partial thickness damage)

• Eschar: brown/black, soft of hard (full-thickness damage)

We should assess the wound using a validated wound assessment tool such as the Bates-Jensen Wound Assessment tool [2]. Skin grafting can be done in the presence of well-vascularized peritendon and periosteum. Marginal wound re-epithelization is seen to occur in chronic wounds, which grows into the tissue and interrupts the lateral reconnections of the graft. Hence, it is advisable to do sharp excision of the margins with a blade before grafting.

Quantitatively, the bacterial level must be less than 10⁵ bacteria per gram of tissue for a successful skin grafting. Clinically, the wound should be “clean” and debrided of all necrotic tissues. The chief aims of treatment should be the control of the infection and the promotion of the natural processes of healing [3]. The necrotic tissue debris physically impedes and chemically decelerates ingrowth of blood vessels into the skin graft. Necrotic tissue and slough are the key contributors to wound chronicity, and thus, debridement is necessary for wound healing [4]. Those wounds that are left open for many days contain heavy bacterial contamination and therefore need to be substantially debrided before skin grafting. Sharp debridement leads to the release of cytokines and mediators of inflammation [5]. The various debridement techniques [6] used to prepare the recipient site include the following:

Debridement Type	Definition	Examples
Mechanical	Use of external mechanical method for debridement of necrotic tissue	Wet-to-dry gauze, water spray, whirlpool, wound wash
Enzymatic	Use of topical agent containing proteolytic enzyme which can help slough separation	Collagenase; Papain urea
Surgical	Surgical debridement of necrotic tissue using sharp instruments	Scalpel, scissor, curette
Autolytic	Separation of necrotic tissue by natural process due to proteolytic enzymes liberated by wound surface and bacteria colonizing the wound	hydrocolloids, hydrogels, alginates, hypertonic dressings aid autolytic process
Biologic	Use of medical grade maggots to achieve wound debridement	Larval debridement therapy [7]

Conservative Sharp Wound Debridement (CSWD) is a suitable method of debridement when there is dead necrotic tissue such as slough or eschar, callus-tissue around the wound, or hyperkeratosis (which is clearly demarcated from the healthy tissue, where other types of debridement may not give optimum result and/or where speed is essential) [2].

It has been understood that a “granulating” wound has better chances of skin graft take. Active bleeding of the wound bed can lead to hematoma collection under the graft, thereby inhibiting graft take. Adequate hemostasis can be performed using electrocautery and suture ligation.

Before skin grafting, the surrounding soft tissue can be adjusted to cover critical structures such as tendons or bones if they are exposed without peritendon or periosteum. A moist wound environment has been shown to accelerate wound healing by up to 50% compared with exposure to air [8]. Vacuum-assisted closure therapy or dermal substitutes can be used to prepare small areas of tendons and bones, by growing granulation tissue from the sides.

2.2 Functional consideration

An optimum skin graft can give a good functional and esthetic skin reconstruction. Particular attention should be given to the size of graft needed, the degree of wound contraction anticipated, the color and texture of the skin required, and the need for adnexal glands. More the amount of dermis in the skin graft, lesser is the amount of wound contraction.

Full-thickness grafts provide excellent cosmetic results since they include the complete epidermis and dermis and thereby have minimal contraction. Full-thickness skin grafts are commonly used for syndactyly release, nipple-areola reconstruction, or ectropion release. Full-thickness graft donor site is limited and can be increased by tissue expansion before harvesting.

The donor sites of very thin skin grafts like epidermal grafts heal quickly with minimal contraction, but do not resist the recipient wound contraction. This is desirable on areas such as large scalp wounds and abdominal wounds, where wound contraction leads to gradual pulling of the wound edges together, reducing the skin graft requirement. In a second stage surgery, the contracted skin graft can be excised and the wound can be primarily closed to get better functional and esthetic results. The skin thickness varies from upper eyelid (thin) to trunk and leg (thick).

2.3 Esthetic considerations

The final appearance of skin graft color is dependent upon skin texture, melanin pigmentation, and blood flow. According to Gillies’ principles, like should replace like. So the replacement of tissue from a similar or surrounding site gives the best color match [9]. For face, full-thickness skin grafts are preferred from sites such as supraclavicular, posterior auricular, upper eyelid, or scalp [10]. For nipple-areola complex, skin grafts from the contralateral areola or genitalia may be used. Glabrous skin grafts from hypothenar area can be placed over palms and soles of feet.

3. Conclusion

Preparation for a successful skin grafting entails the optimization of patient factors including systemic and local tissue environment, in addition to consideration of functional and esthetic factors. The author has experienced that the simpler techniques of mechanical as well as sharp surgical debridement followed by negative pressure wound therapy in appropriately selected patients (as shown in Figures 1–8) fetch almost cent percent skin graft take results, with both functional and esthetic targets achieved.

Figure 1.

Foreaarm Infected wound management by debridement followed by NPWT dressings and Skin grafting.

Figure 2.

Abdominal wound management by debridment and NPWT dressing.

Figure 3.

Thigh wound bed preparation by noormal saline dressings.

Figure 4.

Forearm wound preparation by topical antibiotic ointments.

Figure 5.

Diabetic foot wound bed preparation.

Figure 6.

Great toe raw area wound preparation by debridement and NPWT.

Figure 7.

NPWT dressing for pressure ulcers.

Figure 8.

Diabetic foot ulcer- wound bed preparation by debridement and normal saline dressings.

Conflict of interest

The authors declare no conflict of interest.