The recovery of post-burn hypertrophic scar in a monitored pressure therapy intervention programme and the timing of intervention

Abstract

Introduction: Pressure therapy used to be considered as the mainstay non-invasive treatment of hypertrophic scar. However, the maturation process of hypertrophic scar during pressure therapy process has seldom be reported. Moreover, although early application of pressure therapy after burn injuries is reco6mmended, minimal evidence exists to support it. This study aimed to examine the maturation trajectory of post-burn hypertrophic scars in a 6-month monitored pressure therapy intervention programme and investigate the difference in the trajectory between patients receiving early intervention and patients receiving late intervention.

Methods: Thirty-four patients with sixty-five post-burn hypertrophic scar samples were recruited for the study. All the subjects were treated with a 6-month pressure therapy programme with the pressure dosage regulated using a newly developed pressure therapy system, the Smart Pressure Monitored Suits. The selected scars were assessed with MiniScan XE Spectrocolorimeter on scar pigmentation, and Terason t3000 portable ultrasound imaging equipment on scar thickness. The Vancouver Scar Scale (VSS) was used to evaluate pigmentation, pliability, vascularity and height of the scars. Subjects' report of pain and itch was documented. Assessments were conducted before treatment began and then monthly during the 6 month-intervention process. Patients were further divided into two groups according to the time of intervention post-burn injuries to review differences in the maturation trajectory between those who received early versus late treatment (early intervention group, prescribed within 60days after injuries; late intervention group, prescribed after 61 days). The changes of scar features were recorded to formulate the recovery trajectory of scar, and the outcomes of intervention between the early and the late groups were compared.

Results: Pre- and post-treatment comparison demonstrated significant improvement in scar pigmentation, thickness, VSS scores and scores of pain and itch (p<0.01) for the early intervention group. For the later intervention, only scar lightness, yellowness, VSS scores and scores of pain and itch was found with significant improvement (p<0.01). The improvement in these scar characteristics was sustained over time during the treatment process. The early group demonstrated superior effect in improving scar lightness, yellowness (p<0.01), thickness (p<0.01), pigmentation score (p<0.05) and pain score (p<0.01) than the late group in comparison between the two groups at similar post-burn timing.

Conclusions: Hypertrophic scars appeared to undergo continuous improvement in the appearance, pain and itch over time during the process of a monitored pressure intervention programme. Early application of pressure therapy after burn injury may contribute to better outcomes as shown by their faster recovery than those with late intervention. In order to achieve the best outcomes, regular evaluation and adjustment for optimal interface pressure is necessary.

Keywords: Hypertrophic scar; Monitored pressure therapy; Smart Pressure Monitored Suits (SPMS).