All patients enrolled in this study were their own controls with two STSG donor sites per patient. Each patient had two skin graft donor sites, one on each thigh, with one site treated with negative-pressure wound therapy dressings and the other treated with conventional dressings using petroleum gauze without application of negative pressure. The assignment of dressing methods was randomized using a simple randomization technique.

Split-thickness donor site wound management All skin grafts were consistently harvested from the proximal anterolateral thigh region, using an electrically powered dermatome (Zimmer, Zimmer Surgical Inc.). The thickness of the skin grafts was uniformly set at 0.3 mm to minimize variability across cases.

All patients enrolled in this study were their own controls with two STSG donor sites per patient. Each patient had two skin graft donor sites, one on each thigh, with one site treated with negative-pressure wound therapy dressings and the other treated with conventional dressings using petroleum gauze without application of negative pressure. The assignment of dressing methods was randomized using a simple randomization technique.

Split-thickness donor site wound management All skin grafts were consistently harvested from the proximal anterolateral thigh region, using an electrically powered dermatome (Zimmer, Zimmer Surgical Inc.). The thickness of the skin grafts was uniformly set at 0.3 mm to minimize variability across cases.

In the NPWT method, we first applied non-adherent petroleum gauze to the donor site wound. The NPWT system (Model: NP-800, Medway Inc., Suwanee GA, USA) was then fixed, and the pressure was continuously set to 100 mm Hg for seven days. On the 7th postoperative day, the NPWT system was removed and replaced with a conventional dressing while keeping the inner petroleum gauze dressing in situ.

The time to complete re-epithelialization, or healing time, was defined as the number of days required to achieve full epithelialization of the donor site, with no further need for wound dressing. Epithelialization was considered complete when the entire wound area of the STSG donor site was covered with epithelium.

The re-epithelialization was assessed on the 14th day after completely removing the dressing from both donor sites. Photographs of the donor sites were taken, and the percentage of epithelialization was quantified by analyzing the images using histogram-based image processing software (Adobe Photoshop R). The histogram depicts the distribution of pixels in an image by graphing the number of pixels at each color intensity level. The non-epithelialized area was initially identified and selected using the color range tool. The Fuzziness toolbar was then adjusted to select any missing tissues, including the entire non-epithelialized area. The number of pixels within the selection was determined, and the percentage of epithelialization was calculated by dividing the number of pixels in the non-epithelialized area by the total number of pixels within the total donor site wound surface area.

Pain was objectively assessed using a visual analog scale, which scored the pain from 0 (no pain) to 10 (worst pain). The pain intensities of both sides of the donor site wound were recorded, and each patient reported their feelings of pain at the donor site wound on postoperative days 1, 2, 3, and 7.

3-mm punch biopsies were taken from the NPWT and the control donor areas on the 14th postoperative day to compare the histological response to wounding. Each specimen was fixed in 10% formalin solution for 24 hours, then processed for paraffin embedding. Paraffin sections (4 µm thickness) were cut and stained with hematoxylin and Eosin stain (H&E). Four photomicrographs (at a magnification of x100) from non-overlapping fields were taken from each H&E -stained slides from each skin biopsy specimen and were examined by the image-J software. Thickness of the epidermis in micrometers (µm) was measured at different three sites in each photomicrograph from H&E -stained slides, from the top of the stratum granulosum to the basement membrane of stratum basale at the dermo-epidermal junction (DEJ) at the top of dermal papillae with exclusion of sites of the epidermal papillae.

An immunohistochemical (IHC) staining of formalin-fixed paraffin-embedded skin sections using anti-CD45 marker (rat m