Chlorhexidine-impregnated Tulle Gras Versus Polyethylene Nonadhesive Film for Dressing of Donor Site Wounds in Cases of Split-thickness Skin Graft

In wound care, restoration of an intact skin barrier is of utmost importance to prevent infection, minimize wound contraction, and to maintain function.¹ Skin grafting represents a very rapid and effective method of repairing the skin defect but creates a new donor site wound after the sheet of skin has been harvested. Depending on the thickness, site, size of the wound, and age of the patient, the donor site wound should re-epithelialize completely in 7 to 21 days.²

Donor site wounds are painful, and a delay in healing increases patient morbidity. Optimum local care for these donor sites should not only promote efficient wound healing but also be cost-effective and prevent pain, discomfort, infection, hypertrophic scarring, and hyperpigmentation. This study was done to obtain clarity on a low-cost, painless, comfortable wound cover for donor sites.

The objectives of this study were to compare the efficacy of chlorhexidine-impregnated tulle gras and polyethylene nonadhesive film dressing for STSG donor site wounds. Primary dressings that utilize moist wound healing principles, such as hydrocolloids and film dressings (ie, polyethylene drape), may be preferable to traditional mesh gauze dressings in the management of STSG donor sites.³

A prospective, randomized, comparative, observational study was carried out over 2 years in 60 patients in a tertiary care center in Mumbai, India, to compare the efficacy of chlorhexidine-impregnated tulle gras (n = 30) with sterile polyethylene film (n = 30) for donor site dressing after STSG. The tulle gras was a ready-to-use, presterilized dressing evenly impregnated with soft, white paraffin containing chlorhexidine acetate 0.5% w/w (conforming to BP 1993) to facilitate nontraumatic removal of the dressing and prevent infection in the donor site area. Plain tulle gras and antibiotic-coated polyethylene dressings were not available at the authors’ institution; however, donor sites are clean wounds, and therefore antibiotic coating or impregnation were not anticipated to influence the rate of wound healing of the donor sites.

Randomization tables were used to assign patients to treatment. Patients younger than 65 years of age and whose donor site area was less than 30 cm × 15 cm were included in the study. Pregnant women, patients with keloidal tendencies, patients with poorly controlled diabetes or hypertension, and patients with renal or hepatic dysfunction were excluded from the study. The study was initiated after obtaining approval from the Institutional Ethics Committee. A complete preoperative assessment was done for all the patients who met the inclusion criteria described above. Wounds chosen for skin grafting were posttraumatic, postinfective, or the result of severe burns. Written informed consent was obtained from all patients (or guardians if the patient was under 18 years of age).

STSGs were harvested from the thigh area of each patient using the same Humby skin grafting knife with constant settings on the handle for graft thickness. All the procedures were done or supervised by 2 senior consultants with similar experience in harvesting skin grafts. Exact similarity in graft thickness can be achieved only with an electric dermatome, which was not available at the authors’ institution.

In both groups, highly absorbent cotton Gamjee pads were used above the primary dressing. In the polyethylene film group, additional slits were made on the film after which the Gamjee pads were applied. The donor area was further immobilized by application of an elastic compression dressing. In all patients, the donor site dressing was monitored for excessive saturation.

On day 14 after STSG, the dressing was changed. To reduce pain, bleeding, and discomfort, normal saline was used to wet the old dressing before removal. With the dressing removed, the status of epithelialization was assessed; the presence or absence of complete epithelialization was noted. This assessment was done by subjective evaluation and through measurement of the epithelialized wound area compared with measurements done preoperatively. Digital image analysis or pie graphs were not used. The wound was also examined for other sequelae, such as slippage and exudate formation during the change of dressing. The patient’s pain score was also calculated during removal of the dressing by using the VAS, ranging from 0 (no pain) to 10 (intolerable pain). This score was calculated separately for each patient and for each type of dressing. Since the authors’ institution serves a population with low literacy rates, patients were also asked to assign a “comfort score” for the dressing used for their wounds. In this nonstandard, 3-point scoring system, patients rated the dressing as a 1 (comfortable), 2 (mildly uncomfortable), or 3 (extremely uncomfortable).

Follow-up was done at day 21 and subsequently at 3 months and 6 months to look for late sequelae related to the dressing type, such as hyperpigmentation and hypertrophic scarring. The results were analyzed using a social science statistics calculator and SPSS software (v16.0; IBM). A P value <.05 was considered statistically significant.

In the current study, 60 patients undergoing STSG were randomized into 2 groups. Chlorhexidine-impregnated tulle gras was applied to the donor site in 30 patients, while polyethylene nonadhesive film was used in the other 30 patients.

The mean age of patients in the polyethylene film dressing group was 33.6 years, compared with 35.2 years in the tulle gras group (Table 1). Most patients in both groups were male (mean, 68%).

On evaluation on Day 14 after STSG, 25 patients in the polyethylene dressing group (83.4%) reported a comfort score of 1 (comfortable), whereas only 7 patients in the chlorhexidine-impregnated tulle gras group (23.3%) rated their dressing as a 1 for comfort (Table 2). In the polyethylene film group, 4 patients (13.3%) rated their dressing’s comfort score as 2 (mildly uncomfortable) compared with 22 patients (73.4%) in the polyethylene nonadhesive film group. These differences were statistically significant (χ² = 22.5865; P=.000947).

As seen in Table 3, 28 patients (93%) in the polyethylene film group had healed completely compared with 27 patients (90%) in the chlorhexidine-impregnated tulle gras group; this difference was not statistically significant (χ² = 0.2182; P=.994465). The mean time to complete epithelialization was 14.9 days in the polyethylene film group and 15.2 days in the chlorhexidine-impregnated tulle gras group.

Table 4 shows the mean pain scores on day 14. In the polyethylene film group, 29 patients (96.7%) had a pain score of less than 5 compared with 17 patients (56.7%) in the chlorhexidine-impregnated tulle gras group; this difference was statistically significant (χ² = 13.416; P=.009412). The mean day 14 pain score for the polyethylene film group was 4.7 versus 5.5 for the tulle gras group.

As shown in Table 5, 22 patients (73.3%) in the polyethylene film group did not show any early sequelae/complications compared with 19 patients (63.3%) in the chlorhexidine-impregnated tulle gras group. This difference was not statistically significant (χ² = 1.7146; P=.988546).

Slippage of the dressing was seen in 16.7% (5 patients) of each study group. There was a higher incidence of dressing saturation and yellow exudate from the donor site area in the chlorhexidine-impregnated tulle gras group.

As shown in Table 6, 25 patients (83.3%) experienced no late sequelae in the polyethylene film group compared with 13 patients (43.4%) in the chlorhexidine-impregnated tulle gras group; this difference was not statistically significant (χ² = 10.336; P=.111179). Hyperpigmentation was seen in 10% and 33.3% of patients in the polyethylene film group and chlorhexidine-impregnated tulle gras group, respectively.

The common causes of wounds in the authors’ institution are diabetic foot ulcers, venous ulcers, peripheral vascular disease, posttraumatic infected wounds, and posttraumatic tissue defects.  In many of these cases, skin defects are closed with STSG. In the postoperative period, patients frequently experience more pain at the donor site than at the recipient site, ultimately making the patients reluctant to undergo further procedures. To date, there is no consensus regarding the optimal donor site dressing that would result in early healing with minimal or no pain at the donor site.

Several authors have observed that maintaining a moist environment over the wound site reduces pain considerably. In 1962, Winter demonstrated that moisture enhances wound re-epithelialization and angiogenesis, thus accelerating the healing rate.⁴

In the current study, the authors compared polyethylene nonadhesive film with chlorhexidine-impregnated tulle gras as donor site wound dressings. On review of literature, only 1 study was found in which polyethylene nonadhesive drape dressings and banana leaf dressings were compared for donor site coverage.⁵

The aim of the current study was to compare the 2 dressings with respect to status of complete epithelialization at day 14, comfort score, pain score, and early and late sequelae of wound healing. The age and sex distribution of cases were similar in both groups.

With regard to dressing comfort, 83.4% of patients in the polyethylene film group gave a comfort score of 1, which was significantly more than the 23.3% of patients in the chlorhexidine-impregnated tulle gras group. In the polyethylene film group, 13.3% of patients had a comfort score of 2 compared with 73.4% of those in the chlorhexidine-impregnated tulle gras group. In 2013, Gore et al also found that polyethylene nonadhesive film dressing was more comfortable for donor site wound dressing.⁵

In the current study, 96.7% of patients in the polyethylene film group had pain scores <5, significantly more than the 56.7% of patients in the chlorhexidine-impregnated tulle gras group (P =.009412). Of note, only 1 patient (3.3%) in the polyethylene film group had a pain score >5 compared with 13 patients (43.3%) in the chlorhexidine-impregnated tulle gras group. In the Gore et al study, polyethylene dressings were associated with significantly less dressing removal pain and background pain than the banana leaf dressing comparator; the VAS 10-point pain scores also gradually decreased with duration of use.⁵ On day 3 of the Gore et al study, mean postharvest pain score was 2.88 for the polyethylene film dressing, and the mean dressing removal pain score was significantly less (2.34 on day 7 and 2.00 on day 9 postharvest) for polyethylene-covered areas.⁵

Pawar et al compared Melolin (Smith & Nephew) polyethylene dressings, collagen, and petroleum jelly-impregnated gauze and reported mean VAS scores of 3.6, 2.73, and 5.2, respectively.⁶ The petroleum jelly-impregnated gauze group had the highest pain score. Similarly, a 2017 single-center, randomized, controlled study found that transparent, breathable film dressings were associated with less severe pain than reported with cotton gauze.⁷

In the current study, rates of complete healing in both groups were comparable, with 93% of patients in the polyethylene film group achieving complete healing on day 14 compared with 90% of patients in the chlorhexidine-impregnated coated tulle gras group. The mean times to complete epithelialization in the polyethylene film group and the chlorhexidine-impregnated tulle gras group were 14.9 and 15.2 days, respectively. Epithelialization was evaluated by subjective analysis and comparison of wound size on day 1 versus the area of epithelialization on day 14; Bloemen et al found that subjective analysis of wound healing is reliable.⁸ Gore et al found that epithelialization was complete between the seventh and ninth postharvest days in the polyethylene drape group; 98% of patients in this group had healed completely by the ninth postharvest day.⁵ The mean number of days required for complete epithelialization in this group was 7.57 days±0.993 day.⁵ Of note, the polyethylene and banana leaf dressings were applied on different sites of the same patient’s thigh in each of the participants; this may confound interpretation of healing rates, which can differ from patient to patient. Since the present study randomly assigned patients into 2 groups in which only 1 type of dressing was used per group, the wound healing rates reported in this study may better reflect real-world variations.

In a 2020 study comparing collagen, chlorhexidine-impregnated tulle gras, cellulose acetate mesh, and hydrocolloid dressings, Sharma et al found a significantly longer time was needed for wound healing in the chlorhexidine-impregnated tulle gras group.⁹ A 2021 study by Dave et al also had similar findings when comparing wound healing times with chlorhexidine-impregnated tulle gras versus collagen dressings.¹⁰ Similarly, Pak et al reported longer wound healing rates for petroleum jelly-impregnated gauze than for povidone iodine foam dressings.¹¹ In the Kazanavičius et al study, the mean healing period was 14.76 days in the cotton gauze group compared with 10 days in the transparent breathable film group.⁷ Topical amiloride-soaked dressings have also been found to have a faster healing rate and better scar quality compared with those associated with chlorhexidine-impregnated tulle gras,¹² and nanofibrillar cellulose has been found to provide more efficient wound healing than that of polylactide copolymers.¹³ Lee et al examined dialkylcarbamoyl acetate combined with chlorhexidine gauze and found this showed better healing rates than those of conventional foam dressings.¹⁴

In the current study, 73.3% of patients in the polyethylene film group did not show any early sequelae compared with 63.3% of those in the chlorhexidine-impregnated tulle gras group; this result was not statistically significant. Slippage and dressing saturation were seen in 16.7% and 6.7% of patients, respectively, in the polyethylene film group, compared with 16.7% and 10%, respectively, in the tulle gras group. Yellow exudate formation was seen in 1 patient (3.3%) in the polyethylene film group compared with 3 patients (10%) in the chlorhexidine-impregnated tulle gras group. In the Gore et al study, dressing saturation with seepage of yellow exudate was seen in 42% of patients with the polyethylene drape.⁵ This issue can be avoided by making slits in the polyethylene film and covering the primary film dressing with a Gamjee pad, as was done in the current study. Horch et al compared collagen dressings with polyurethane film and found that hematomas and seromas requiring aspiration were more prevalent in the polyurethane group.¹⁵ In a study comparing local phenytoin, polyurethane drape, and framycetin-coated dressings, the incidence of pain was highest in the framycetin group, while there was a higher incidence of fluid leak in the polyurethane group.¹⁶

In the present study, 25 of 30 patients (83.3%) in the polyethylene film group had no late sequelae, compared with 13 of 30 patients (43.4%) among the chlorhexidine-impregnated tulle gras group. This result is not statistically significant.

The late sequelae of hyperpigmentation and hypertrophic scarring were seen more frequently among patients in the chlorhexidine-impregnated group (33.3% hyperpigmentation and 23.3% hypertrophic scarring) than in the polyethylene film group (10% hyperpigmentation and 6.7% hypertrophic scarring). Patients with history of keloidal tendencies were excluded from the study.

The polyethylene nonadhesive film dressing was found to be a good alternative to the conventional tulle gras dressing and was tolerated well by the patients, giving superior comfort. Also, it was associated with significantly less pain compared with conventional dressings. Late sequelae, such as hyperpigmentation and hypertrophic scarring, were less prevalent in the polyethylene film group.

Exact similarity in depth of the skin graft wounds across all the participating patients could have been achieved only with the use of an electric dermatome; this could not be done at the authors’ institution due to nonavailability of an electric dermatome and cost considerations. The study was conducted in a limited sample and for a limited donor area. Further studies need to be done with larger donor wound areas and include patients with poorly controlled comorbidities that affect wound healing to validate the study findings.

In the literature, studies comparing polyethylene dressings with banana leaf dressings have shown definite benefits of polyethylene nonadhesive dressings. Although both dressings were available in the authors’ institution, the cost of 150 cm × 150 cm polyethylene drape was approximately 60% less than the cost of a roll of chlorhexidine-impregnated tulle gras. This represents a cost-saving, effective alternative for use in a third-world country.

Polyethylene nonadhesive film also has advantages over chlorhexidine-impregnated tulle gras dressing in terms of reducing pain and providing more patient comfort. Hence, it is a safe, comfortable, easily available, and effective alternative donor site dressing for use after STSG.