Skin grafting is the easiest and the most reliable way to obtain proper wound coverage. However, the two major concerns of skin grafting are the poor color match in the recipient sites and donor site morbidity including pain, discomfort, and hypertrophic scarring. Major pigment mismatches are common in split-thickness grafts particularly in darker skinned patients including Asians (Fig. 1). Several factors may play a role in the color mismatch of a regular skin graft. These include the amount of melanin, the degree of transfer of melanosomes to keratinocytes, and the number of melanocytes (Carlson et al., 2002; Velangi & Rees, 2001). Because the melanocytes are localized to the basal cell layer of the epidermis, the origin of the color mismatch has been assumed to be in the epidermal melanin (Tyack et al., 1997; Swope et al., 2002). Because regular skin grafts transferred to new locations maintain their epidermal specificity, a pigmentation difference with the surrounding skin is unavoidable.
To minimize the limitations of the classic skin graft, the author has developed a dermis graft, which is a deepithelialized split thickness skin graft, and have reported promising results of the method for coverage of small to medium sized wounds on the body (Han et al., 2007). The important aspects of this method involve the immediate return of the epidermis to the donor site in order to overcome the donor site morbidity and minimize the pigment mismatch between graft and surrounding skin by restoring the epidermal portion of the recipient site through inducing epithelization from the adjacent skin.
The purpose of this chapter is to present usefulness of the dermis graft in a wound coverage.
2. Surgical technique
After sharp debridement of the recipient site, skin and underlying subcutaneous tissue of the wound margin is undermined approximately 5mm in length along the periphery and meticulous hemostasis is obtained. The defect size of the recipient site measures. A thin epidermal flap is elevated on the gluteal area or the lateral thigh using a Zimmer dermatome, in which the thickness is set to 0.010 inches. The blade is then reset to 0.012 to 0.020 inches and the dermis to be grafted is cut from the same area. The previously elevated epidermal flap is replaced on the donor site and sutured with prolene. The harvested dermis is tailored to the size and shape of the defect including the undermined area and transferred
to the recipient site. The edge of the dermis graft is inserted into the undermined wound margin and fixed to the wound bed along the circumference of the defect using PDS sutures. The undermined marginal skin over the grafted dermis is then fixed to the underlying dermis using prolene sutures (Fig. 2). The skin sutures are removed after approximately 5 - 7 days in order to reduce the stitch marks. Sunshine is avoided for the first three to six months using sun-blocking agents.
The dermis graft is indicated in any cases with small to medium sized skin defect (smaller than 42.0 cm2 based on the author’s experience). Especially, a dermis graft is likely to have its greatest reconstructive role on the exposed areas such as the face, neck, forearms, and hands. In fairly large wounds (larger than 42.0 cm2 based on the author’s experience), the return of the patients to their normal daily activities is likely to be delayed because the epithelization of the graft takes a longer time. There is no data on the critical size or thickness of the dermis that can produce scar-free wound healing. Therefore, further study will be needed.
It was found that a full thickness small sized wound, which was left to heal by secondary intention, sometimes resulted in acceptable scarring in a concave area of the skin. In some wounds, however, a period of several weeks or months is required for complete healing, particularly in actinically damaged, fragile skin. Wounds on convex areas of the skin heal rather poorly (depressed scar) via secondary intention. The resultant wound contraction, which is an important clinical component, is not an uncommon problem (Fig. 3). Skin or dermal substitutes, which are currently produced by advanced technology, may replace the regular skin graft (Kuroyanagi et al., 2001; Terino et al., 2001). However, these procedures usually heal with a significantly conspicuous and unfavorable scar (Figs. 4 and 5). Further improvements are required in such technology to obtain a favorably aesthetic result as obtained with the dermis graft method.
4. Author’s experience
4.1. Clinical research
The author has evaluated the efficacy of the dermis graft used for wound coverage by comparing it with that of a regular skin graft (Han et al., 2007). The patients included in the study provided informed written consent for the study, but has not been registered in an official database of the institutional review board.
4.1.1. Patients and methods
From April of 2001 to March of 2004, the dermis graft was applied to 53 patients (17 male, 36 female), ranging in age from 6 to 61 years (average, 36.5 years). The size of the wound ranged from 2.7 to 42.0 cm2, with a mean and a median size of 12.0 and 10.5 cm2, respectively. The recipient sites were located as follows: 8 on the face, 6 on the forearm, 34 on the hand, 4 on the lower extremities, and 1 on the back. Simultaneously, a regular split thickness skin graft procedure was performed on the wounds of approximately the same size and location as the dermis graft in 33 patients. The size of the regular skin graft wound ranged from 2.3 to 42.0 cm2, with a mean and a median size of 14.0 and 12.0 cm2, respectively. The locations of the wound were as follows: 3 on the face, 6 on the forearm, 21 on the hand, and 3 on the lower extremities. This provided an opportunity to compare the results of the dermis graft with those of the regular skin graft. Prior to classifying the patients into the two treatment groups, detailed information of the new procedure (dermis graft), which included the surgical techniques, advantages, and disadvantages, was provided to each patient. The patients were classified according to their compliance. Compliant patients who fully understood and agreed to the new procedure underwent a dermis graft and noncompliant patients who did not want the new procedure underwent a regular skin graft.
The healing time for both groups was compared. The mean follow-up time was 12.4 months ranging from 3 months to 2 years. Twenty-six dermis graft patients and 20 regular skin graft patients had more than a 12-month follow-up period. The scar condition was evaluated in these long-term follow-up patients by two blind observers (plastic surgery residents in training at the author’s institution) after a 12 to 24 month follow-up (average, 15.7 months for the dermis graft group and 15.0 months for the regular skin graft group) according to the Vancouver Scar Scale (VSS), which included pigmentation, scar height, pliability, and vascularity (Vloemans et al., 2003; Sullival et al., 1990). The averaged scores of the two observers were used as data for the analysis.
The patients’ satisfaction for the donor and recipient site was also surveyed in the long-term follow-up patients. The patients’ satisfaction was compared using a Visual Analogue Scale (VAS) with a score of 0 being the worst and 5 being the best. Statistical comparisons for the data of the VSS and the VAS were performed using a Mann-Whitney U-test. P values < 0.05 were considered significant.
The graft take was complete in all patients in both groups. Refilling of the blood vessels and multiple pin point bleeding was observed on the grafted dermis within the first 2 to 3 days. Reepithelization occurred progressively from the periphery to the center of the grafted dermis.
The whole wound of the dermis graft had reepithelialized after grafting within 11 to 20 days (average 15.5+1.9 days). The skin grafted wounds had healed by 7 to 16 days (average 11.8+1.6 days). In the long-term follow-up, good quality skin characteristics were achieved in the dermis graft.
A comparison of the scars at the recipient site, as assessed by the VSS, showed that the dermis graft was superior to the regular skin graft in terms of pigmentation, height, and vascularity (p<0.05). No significant difference in pliability was detected. The overall average VSS scores of the dermis and skin graft were 1.0+1.1 and 1.6+1.1, respectively (p<0.05). The patients’ satisfaction in the dermis graft group, as assessed by the VAS, was also better than that in skin graft group (4.2+0.9 and 3.4+1.1 each).
Regarding the donor sites, the results of the dermis graft were also satisfactory. All the donor sites of dermis graft healed within 9 days (average 7.5+0.8 days). In contrast, those of the regular skin graft required 11 to 16 days to heal (average 12.8+1.1 days). The donor sites of the dermis graft were also superior to those of the skin graft in terms of scar quality and patient satisfaction. The average of overall VSS scores for the donor sites of the dermis graft and regular skin graft were 0.7+0.9 and 1.3+0.7 each (p<0.05). The average VAS scores for the dermis and skin graft donors were 4.1+1.3 and 2.8+0.8 each (p<0.05). There were no significant complications and no functionally relevant scar in either group (Fig. 6).
4.2. Dermis graft on face after removal of skin cancer
The author has evaluated the reliability of the dermis graft for covering defects after removal of non-melanoma skin cancer on the face. Surgical excision of skin cancer leaves a soft tissue defect which requires reconstruction. Proper selection of reconstruction method is the key point to get a successful result on the face. In planning reconstruction for facial defects, reconstructive efforts should start from the safest and least invasive methods while achieving optimal functional and cosmetic outcomes. A variety of methods can be used to cover the defects; healing by secondary intention, a primary closure, a skin graft, and a local flap. Healing by secondary intention usually leaves a significantly conspicuous and unfavorable scar. Darker skin is more prone to hypertrophic scarring or keloids. The role of primary closure for reconstruction after complete eradication of skin cancer on the face is very limited because of defect size and shape. Only small defects with elliptical shapes yield satisfactory results after primary closure. A local flap may provide several advantages, including decreased scar contracture and satisfactory contour, color, and texture match. In some cases, however, a local flap is not feasible, mainly due to the limitation of size and arc of rotation, particularly in young patients. Poor flap design and inappropriate incisions may contribute to unacceptable scars, violation of aesthetic subunits, and resultant disfigurement on difficult-to-treat areas. In addition, compromise of flap vascularity and inadequate wound closure created by insufficient undermining, lack of deep closure, excessive tension, or inadequate approximation of wound edges predispose to unfavorable results.
4.2.1. Patients and methods
Thirty-eight patients (20 male, 18 female) were treated for the facial defects created by the resection of the non-melanoma skin cancer on the face from January 2006 and December 2008. The patients had more than 12-months of follow-up and the clinical records of all patients were reviewed. The patients’ age ranged from 57 to 83 years (average, 68.7±6.3 years). The defect size ranged from 3.3 to 6.5 cm2 with a mean of 5.1±0.9 cm2. The location of the defect was as follows: 17 cases on the nose, 14 in the orbital area, 4 on the cheek, 2 on the temple area, and 1 on the forehead.
Functional and cosmetic outcomes, focusing on scar contracture, pain, itching, scar height, color, texture, and postoperative complications were assessed. The patients’ satisfaction was also evaluated by using a VAS with a score of 0 being the worst and 10 being the best. The patients were followed up for 12 to 36 months (mean, 20.5±6.2 months).
The graft was well taken by all patients. Reepithelization occurred progressively from the periphery to the center of the grafted dermis. The entire dermis graft reepithelialized after grafting within 17 to 27 days (mean, 25.1±2.4 days).
All patients had satisfactory results in both functional and cosmetic matters with high quality skin characteristics. No significant scar contracture was observed and none of the patients complained of pain or itching. In the scar height, 20 scars were flat and 18 scars were slightly depressed. Neither hypertrophic nor keloid scar was observed. In the color parameter, most of the scars (30 scars) showed favorable color match to the surrounding skin (Figs. 7 and 8) and 8 scars were hypopigmented (Fig. 9). Hyperpigmentation or redness was not observed. In terms of the skin texture, favorable smooth texture was obtained in 25 cases and shiny texture in 13 cases. Obviously conspicuous scar was not identified in all cases and no revision procedure was needed to improve scar quality. There were no significant complications and no recurrences were observed during the follow-up. The patients’ satisfaction with the dermis graft was also excellent (mean score 8.3±1.3).
Regarding the donor sites, the results of the dermis graft were also satisfactory. All the donor sites of dermis graft healed within 9 days (average 7.2±1.1 days). There were no significant complications and no functionally relevant scar (Fig. 10).
5. Advantages and disadvantages
The primary advantage of this method is to provide a graft that is similar to the surrounding skin, leaving minimal scars and color mismatch. Since the epidermal portion can be restored by epithelization, induced by the migration and proliferation of adjacent epidermal cells including melanocytes, the density and activity of the melanocytes as well as the precursor melanocytes of the epidermis of the graft become similar to those observed in the adjacent skin.
Regarding wound contraction of the recipient site after dermis grafting, the contraction of myofibroblasts can be inhibited by grafting with a more dermal portion than a regular skin graft. In previous studies, the inhibition of scar contraction was attributed to the amount of dermal collagen rather than to the amount of epidermis (Chou et al., 2001; Rudolph, 1979; Brown et al., 1990). Another advantage of the dermis graft is the quick healing of the donor site without an obvious scar appearance because the epidermis can be replaced immediately to ensure the closure of the donor bed. Hypertrophic scarring is rare, and the level of pigmentation is less than that of the donor site in a regular skin graft. The patient has less donor site pain and discomfort, which is a very important component from the patient’s point of view. Care of the donor site is also very simple. Dermis grafts are feasible for all wounds that are candidates for regular skin grafts including acute facial burns or post facial cancer excisions.
The only possible demerit with dermis grafting is the delay in complete healing of the recipient site. As previously described, there was a 3.7 day delay in graft healing of the recipient site (15.5 and 11.8 days in the dermis graft and the regular skin graft groups, respectively). However, it is believed that the 3.7 day delay would not cause significant trouble, and what ever problems there are can be overcome by selecting suitable sized wounds.
The dermis graft technique for wound coverage is superior to a regular skin graft technique in terms of the aesthetic results of both the recipient and donor sites. The donor site healing process is faster, and the patient’s pain and discomfort can also be reduced significantly. The dermis graft can be used reliably for covering small to medium sized wounds on exposed areas and may be considered as the first choice.