Silver Ion Hydrocolloid Gauze and Self-Adhesive Polyurethane Foam Dressing Combination Therapy Can Better Promote Healing of Skin Graft Donor Area Than Traditional Therapy: A Case Control Study

Autologous split-thickness skin grafting is a common procedure in plastic surgery, burn management, and reparative and reconstructive surgery. Often, the thigh is chosen as the donor site because it has the largest surface area of any limb, is easily accessible, and has firm underlying structures; additionally, any scarring can be hidden beneath clothing.¹ Nevertheless, healing of the donor site has associated problems, including donor site pain,² and problems related to donor site healing are enhanced when a large area is used for skin graft harvest.³ Sometimes, the grafted skin is completely healed while the donor site remains under dressing; delayed healing at the donor site prolongs hospitalization and increases the pain incurred by the patient as well as the cost of treatment.¹ Wound infection or delayed healing can also result in hypertrophic scarring, which affects appearance.⁴ Dressing of intermediate-thickness skin graft donor site wounds has been investigated in a number of studies; however, the optimal dressing remains elusive.⁵

The traditional and widely used method for dressing donor sites involves petrolatum gauze, sterile cotton pads, and compression bandages. However, the development of advanced dressings designed to improve wound healing has resulted in increased use of many different types of dressings made from a wide range of materials.^6-16 When prevention of infection is a primary consideration, wound dressings containing silver may be advantageous.¹⁷

Silver ion hydrocolloid gauze is an advanced dressing with a wet touch layer that will not stick to the wound, while the self-adhesive polyurethane foam dressing encourages moist wound healing, can absorb liquid, and provides a moisturizing effect. Currently, these products are widely used in the management of a variety of wounds, with good results achieved in healing difficult wounds (eg, leg ulcers).^18-21 Self-adhesive polyurethane foam dressings can be used as the outer dressing, and they are effective for dressing donor sites.²² Previous studies investigating silver ion–containing dressings for donor sites suggest they can reduce pain at the wound site and promote skin reepithelization²³ as well as provide superior wound healing, decreased bleeding, and improved appearance after healing.²⁴ 

Therefore, the present authors hypothesized that using the silver ion hydrocolloid gauze and self-adhesive polyurethane foam dressing in combination (AG+foam) for dressing the donor site of autologous intermediate-thickness skin grafts harvested from the ipsilateral thigh would promote wound healing and prevent pain at dressing change. This study aimed to compare the combined use of these products with traditional external dressing method of petrolatum gauze, sterile cotton pad, and compression bandage. The results could assist clinicians and wound care nurses by providing evidence for an advanced dressing method for skin graft donor sites.

Patients

This was a case control study. Patients admitted to the department of plastic and cosmetic surgery from January 2014 to December 2015 were screened. All eligible patients were consecutively enrolled.

Inclusion criteria consisted of requirement for an intermediate-thickness skin graft of at least 40 cm² in size to be harvested from the ipsilateral thigh for plastic surgery and age between 14 and 60 years. Exclusion criteria consisted of serious heart, lung, liver, kidney, or hematological disease; chronic disease (eg, anemia, malnutrition) that would affect wound healing; clear mental illness or cognitive impairment; treatment with glucocorticoids or immunosuppressive drugs; pregnancy or lactation; or loss to follow-up of patients who left the hospital before complete healing of the skin wound was achieved. 

Selection of dressings

The chosen silver ion hydrocolloid gauze was Physiotulle Ag (Coloplast). The self-adhesive polyurethane foam dressing selected was ALLEVYN (Smith+Nephew). The petrolatum gauze and sterile gauze were purchased from Beijing Shengwei’er medical supplies. Cotton pads are routinely packaged and sterilized by supply room staff in the authors’ hospital. The medical bandage was purchased from Shaoxing Zhende medical dressings.

Methods

Each patient was treated differently based on the experience of their own doctor. Forty-eight patients requiring autologous intermediate-thickness skin graft obtained from the ipsilateral thigh were allocated to either the AG+foam group (n = 23) or control group (n = 25) based on the dressings used. For the patients in the experimental group, AG+foam dressing was used. For the patients in the control group, the donor sites were covered with petrolatum gauze, sterile gauze, and compression bandage. Among the 48 patients, all received care from the same 5 attending physicians or associate chief physician, who also performed all skin grafting procedures. 

The skin graft regions received the same preoperative preparations in the 2 groups, and the surgery was performed under general anesthesia. Tumescence solution was injected subcutaneously, the skin was tightened by an assistant, and the intermediate-thickness skin graft (0.3 mm–0.6 mm) was taken with an Electric Dermatome (Zimmer Biomet). For both groups, the skin wound surface was covered with gauze soaked with 1 mg of epinephrine saline, followed by application under pressure of a sterile gauze outer layer for 3 minutes to 5 minutes. In the AG+foam group, after the gauze was removed, the wound was covered with the silver ion hydrocolloid gauze, followed by placement of the self-adhesive polyurethane dressing. No pressure bandage was applied. In the control group, after the gauze was removed, the wound was covered with petrolatum gauze, followed by sterile gauze and then an outer layer consisting of a cotton pad. A pressure bandage was applied over the dressing.

Whether a patient required dressing change was decided by the attending physician. When the dressing was soaked with exudate, a dressing change was performed. Generally, the first dressing change was performed 3 days to 5 days postoperatively. In the AG+foam group, all layers of dressings were changed after the first wound cleaning with saline. In the control group, the petrolatum dressing was left in place and the outer layers were changed. Dressing changes were performed as necessary until complete wound healing was achieved.

Outcome variables

The degree of pain was scored by the patient after the first dressing change using a 10-point numeric rating scale: score 0, no pain; score 1–3, slight, tolerable pain; score 4–6, moderate, still manageable pain; score 7–9, severe, hard to tolerate pain; and score 10, sharp pain. The number of dressing changes before complete healing was achieved was recorded as was the time required for complete healing of skin wounds after surgery. Infection, bleeding, hematoma, and any other factors that delayed healing of the skin graft donor site for each patient were recorded. The evaluating physician was blinded to the patient grouping. If infection occurred, the wound was cleaned and the dressing was changed respective to the dressing type of each group; however, frequency of dressing change increased. Neither local nor systemic antibiotics were administered. If serious infection requiring surgical debridement or replacement for another kind of dressing occurred, the incident was recorded and the patient was analyzed according to the initial grouping.

Complete wound healing, defined as full reepithelialization of the wound surface without any remaining scabs or bloody and liquid exudate, was determined by the 5 attending physicians. The number of days required from the first postoperative day to complete healing was recorded as was the number of dressing changes during this period. The Patient Assessment Scale (PSAS) and Observer Scar Assessment Scale (OSAS) were used to evaluate the degree of scarring 12 weeks postoperatively.²⁵ 

Statistical analysis

All data were analyzed using SPSS 17.0 (IBM). Categorical data are presented as frequencies and were analyzed using the χ² test. Distribution of the continuous variables was assessed using the Kolmogorov-Smirnov test. Nonnormally distributed data are presented as median and interquartile range (IQR) and were analyzed using the Mann-Whitney U test. Normally distributed data are presented as mean ± standard deviation and were analyzed using the Student t test. Two-sided P less than .05 was considered to be significant.

Patient characteristics

All patients completed the clinical observation period, and none were lost to follow-up. Mean patient age was 34.5 years ± 11.8 in the AG+foam group and 32.8 years ± 11.5 in the control group; the proportion of males was similar between the 2 groups (52% and 48%, respectively; P > .05 for both). The proportion of patients who smoked, those with diabetes, the indication for split-thickness skin graft, and the area of the donor site all were comparable between the 2 groups (P > .05 for all) (Table 1). The thickness of the harvested skin graft was 0.45 mm ± 0.02 mm in both groups (P = .950). 

Pain score for the first dressing change

The median visual analogue scale pain score for the first dressing change was 5 (range, 4–6) in the AG+foam group and 7 (range, 6–7.5) in the control group (P < .001) (Table 2). Most patients in the AG+foam group considered the pain of the first dressing change to be moderate and tolerable. In contrast, most patients in the control group considered the pain of the first dressing change to be severe and difficult to tolerate. 

Short-term outcomes

While no cases of infection occurred in the AG+foam group, 2 cases of infection occurred in the control group, which delayed healing. In both cases, the wound exudate culture revealed Pseudomonas aeruginosa; however, neither case was deemed serious. Wound healing occurred more quickly in the AG+foam group than in the control group (mean, 12.7 days ± 2.4 vs 22.0 days ± 5.8; P < .001). Fewer dressing changes were required in the AG+foam group than in the control group (median, 2 [IQR, 2–3] vs 4 [IQR, 2.5–5]; P = .002) (Table 2, Figure 1, Figure 2).

Long-term outcomes

The mean PSAS score was 23.4 ± 2.4 in the AG+foam group compared with 36.2 ± 3.8 in the control group, and the mean OSAS score was 23.9 ± 2.8 in the AG+foam group compared with 36.1 ± 4.4 in the control group (P < .001 for both). The overall scar rating for patients was 5.6 ± 1.1 in the AG+foam group and 7.2 ± 1.3 in the control group, and the observer overall scar rating was 5.3 ± 1.3 in the AG+foam group and 7.2 ± 1.3 in the control group (P < .001 for both). 

The goal of this study was to compare the dressing of donor sites after split-thickness skin grafting with AG+foam dressing vs traditional petrolatum gauze, sterile gauze, and cotton pad. The results indicate use of the former resulted in faster wound healing, with fewer dressing changes and reduced pain at first dressing change compared with the control dressing. The PSAS, OSAS, and overall scar rating scores were also better with use of the advanced dressing. Two cases of wound infection occurred in the control group, whereas none occurred in the advanced dressing group.

Wound dressing of thigh skin donor sites is often done with petrolatum gauze, sterile gauze, and cotton pad with bandage compression. If the skin donor site becomes infected or heals slowly, this will inevitably cause scar hyperplasia, which will affect the appearance of the donor site. The healing time with traditional dressings is approximately 3 weeks, and the presence of considerable exudate requires dressing changes. The subjective experience of the patient can be poor when changing the dressing; additionally, new epithelium is easily damaged, which causes bleeding and prolongs healing time. When exudation is light the frequency of dressing change can be reduced; however, this method is inconvenient for patients wearing pants as the patients can experience pain when the dressings rub against clothing. The use of different advanced dressings for healing donor site wounds has been investigated in several studies, with results supporting that the use of advanced dressings results in faster wound healing, fewer dressing changes, and less pain during dressing change.^6-16

In the present study, good results were achieved with the use of AG+foam dressings at the skin donor site. These results are supported by other studies in which dressings containing silver ion were used.^23,24 Advanced dressings can provide a moist environment for wound healing, which is of benefit to the growth of the epithelium; healing time is significantly shortened as a result.^26,27 Because of the moisture retention characteristics of AG+foam dressings, the dressing does not adhere to the wound when it is removed, which effectively reduces both damage to the new epithelium and pain during dressing change.²⁸ The exudate can also be effectively managed using the self-adhesive polyurethane foam dressing. Advanced dressings have less absorptive capacity than traditional dressings; however, unlike changing a traditional dressing, early and timely changing of advanced dressings is not delayed by adherence to the wound bed. 

The self-adhesive polyurethane foam dressing is designed to be easy to use, and the polyurethane film on the back is impervious to water. The dressing does not affect the patient when wearing pants and does not contaminate clothing. The patient can shower with the dressing on, thereby facilitating self-management. The donor site wound after skin graft is sterile. The silver ions released from the AG in the wet environment have an antibacterial effect. This effect can inhibit the growth of many types of bacteria, reduce the release of inflammatory mediators, effectively prevent infection, and promote wound healing.²⁹ Nevertheless, the indications for the use of silver ion dressings on noninfected wounds remain controversial.³⁰ In the authors’ study, no infection occurred in the AG+foam group, but 2 cases of P aeruginosa infection occurred in the control group. Infection in the control group may have occurred owing to the large size of the skin graft area, which complicates bandage fixation and may result in loosening of the dressing and failure to achieve timely replacement. The silver sulfadiazine content in unit area of AG is low—much lower than the recommended maximum daily dose. The phenomenon of black staining or silver poisoning caused by the oxidation of silver ions³¹ was not found in this study. In addition, some reports exist of silver toxicity to the host cells and longer time to reepithelialization of skin graft donor sites^17,32; however, these phenomena were not observed in the present study. More rapid healing with use of silver hydrocolloid dressings has been reported in other studies,^12,23 which supports the findings of the present study. The more rapid healing time could be due to the wet dressing or to unknown factors. The type of silver compound could also affect outcomes such as the number of dressing changes,¹⁷ but this was not observed in the present study. These points warrant further study.

The theory of moist healing is an important achievement in the field of wound healing. Since the 1970s, various functional dressings have emerged,³³ and profound changes have occurred in the dressing of different wounds.³⁴ The theory of moist wound healing is still ongoing. Determining how to better manage wound exudate and keep the local wound in the moisture balance are problems faced by every clinician and nurse. The study reported here can be regarded as a comparison of the traditional dry wound healing dressing and the wet wound healing dressing. 

The study is limited by its small size; additionally, it was undertaken at a single center. Larger randomized controlled trials are needed to fully evaluate the efficacy of the advanced dressing method.

In the present study, AG+foam dressing shortened healing time, reduced the number of dressing changes, reduced pain at first dressing change, and improved the appearance of scarring compared with traditional dressing methods. The advanced dressing method warrants further investigation with larger interventional studies. 

Authors: Zhi Wang, MD; Xiao Long, MD; Jiuzuo Huang, MD; Ang Zeng, MD; Zhifei Liu, MD; and Xiaojun Wang, MD

Affiliation: Department of Cosmetic and Plastic Surgery, Peking Union Medical College Hospital, Beijing, China

Correspondence: Xiaojun Wang, Department of Cosmetic & Plastic Surgery, Peking Union Medical College Hospital, Beijing, China; pumchwxj@163.com 

Disclosure: The authors disclose no financial or other conflicts of interest.