Split Thickness Skin Grafting (STSG) is a well-known and established procedure for healing burn wounds throughout the world. The procedure requires the removal of the epidermal and part of the dermal layer of the skin. It leaves intact the deep reticular dermal layer which is known as the donor site, and has sufficient cells to regenerate the excised superficial layers. STSG provides wound closure and accelerated healing for the burn wound, and there is great importance surrounding the success of graft take and scar management thereafter (Demirtas et al, 2009; Atiyeh et al, 2002).
The presence of donor sites, though created to assist healing of the burn site, in fact creates an additional wound for the patient which often causes further psychological stress at a traumatic time in the healing process (Andrews, Brown, Drummond, & Wood, 2010). Donor sites are consistently identified as a particularly painful wound by burn patients. Pain associated with burn surgery has been shown to delay the patients return to work and daily functional activity (Wisley et al, 2010; Druery et al, 2005; Brown et al, 2008). Thus, protection of the remaining epidermal and dermal elements of this surgical wound (donor site) is required to assist effective tissue healing with minimal scarring.
One intervention that may accelerate healing and reduce scar formation is the use of Interim Pressure Garment Therapy (IPGT) which applies 4 – 6mmHg of pressure to the thigh. This treatment has been utilised at a major Australian burns unit in Queensland by Occupational Therapists. However, this has involved inconsistent application with a focus on securing wound dressing rather than scar management. Despite this, anecdotal and observational evidence suggests that pressure therapy also makes a difference to some patient’s scar outcomes for donor sites. It is hypothesised that IPGT may improve postoperative management of donor sites through the application of a low superficial pressure that mimics normal skin tension, possibly preventing donor wound distension and subsequent micro-tears in the newly forming epidermis. Furthermore, this may reduce the effects of the inflammatory response, which may in turn give rise to a hypertrophic scar response in the later stages of the healing process.
This research focuses on a unique area of burns donor site scar management. It is designed to test a low pressure tubular support garment as an intervention for the support of, and reduction of donor site scarring. No known studies of this nature have been carried out to date, suggesting there is a need for rigorous clinical evidence to support the use of these garments for donor site scar minimisation. Thereby, two studies were undertaken. The objective of the first study was to determine the pressure range (mmHg) applied by the Interim Pressure Garment Therapy (IPGT). Forty seven healthy adult volunteers were measured and fitted with a pair of Interim Pressure Garments (IPG). The garments were made onsite from a tubular knit material, similar in style to that of a support pant. In the absence of a consistent sizing chart for the reliable fitting of the IPG, a multiple regression analysis was used to design a sizing guide, with the aim of ensuring a standard pressure was applied to the thigh at the first fitting. The amount of pressure beneath the IPG was then determined using a thin pressure sensor pad of the Pico Press®, positioned under the garment on the thigh. The sensor was placed at the same height anatomically for each participant. The interim garments provided a range of 3 to 5.8 mmHg on the donor site thigh locations. This pressure range is low in comparison to other pressure garment therapies (10 - 40 mmHg) that have been reported to have an effect on burn scar formation (Quinn et al, 2010; Engrav et al, 2010). Obtaining these measurements assisted in establishing a baseline size chart for the consistent fitting of the interim garments for the main study.
The second study was designed as a single centre, single (assessor) blinded, randomised, control trial in patients with burns donor sites to their thigh. Patients were randomly allocated into a control group (with no pressure to donor sites), and an experimental group (with Pressure to donor sites) as the comparative treatment. Groups were compared at baseline regarding the important prognostic indicators – age, donor site location, depth, size, and time since graft. The IPGT was administered post-operatively between days 3 to 8 and was dependent on wound review and patient pain. Patients were asked to continue to wear the pressure garment 23 hours per day for a period of 8 weeks, and were given 2 pairs of pressure garments. Follow up assessments and garment replacement were carried out fortnightly for a period of 2 months.
Donor site wound healing was measured using the following tools; a high frequency, high resolution ultrasound scanner which objectively captures and reproduces skin thickness (Dermascan-C ®), a self-contained and battery operated device which provides objective measurements of erythema and melanin based on the light absorption characteristics of human skin (DSM II ColorMeter ®), and The Patient Observer Scar Assessment Scale (POSAS) which measures scar qualities using a range of indicators such as pigmentation, pain, and overall scar appearance. In this study, data were collected for eight patients and is presented as a pilot for this thesis. The results indicated a trend towards a decrease in donor site scar thickness over time for the IPGT group, compared to the control group.
Overall, the results from these studies support the hypothesis that the application of IPGT as a treatment for burns donor sites may support donor site healing and consequently reduce scar thickness. However, continuation of this research will be required to consolidate this evidence and therefore, the limitations and future directions of the studies are discussed.