32 Does the Use of Silicone Gel Sheeting Impact the Overall Physiology of Hypertrophic Scar Development? A Feasibility Trial Using Laser Doppler Imaging to Assess Perfusion in Native Skin and Immature Burn Scar

Abstract Introduction The use of silicone gel sheeting (SGS) has long been observed clinically as an effective modality in reducing hypertrophic scar (HTS) formation. Although the use of SGS is widely accepted, the exact mechanism is not fully understood. Prevailing theory suggests silicone suppresses collagen production in immature active scar. Collagen production is enhanced as blood flow increases in areas of scar hyperemia. Reduction of blood perfusion to the immature scar may act as a potential mechanism in limiting excessive scar proliferation. Methods Laser Doppler Imaging (LDI) was used to assess 2 areas in 2 subjects (85% TBSA w/ CEA and native skin control): A control site and SGS testing site were traced on the skin of each subject and 5 LDI scans were performed on both subjects: 1) initial without SGS; 2) initial with SGS applied; 3) 4-hours post-SGS application with SGS on; 4) 4-hours post-SGS application immediately after removal; 5) 15-minutes post-SGS removal. The control and testing site for both subjects were then analyzed using the LDI software and the average perfusion units (PU) over the region of interest (ROI1: testing site; ROI2: control site) areas were calculated for each scan. Results Perfusion within both ROI had a marked increase in perfusion for HTS scans after 4-hours when compared to the initial scan. However, after initial SGS application to ROI1, the mean PU decreased by 23.1% while the perfusion to ROI2 remained relatively constant (-5.8%). Subsequently, the ROI2 increased in mean PU by 23.4% 4-hours after the initial scan while the ROI1 showed a blunted response in perfusion in comparison increasing by only 2.3%. Conclusions Perfusion for both NS and HTS were notably decreased when SGS was applied compared to the matched ROI without SGS. In addition, prolonged SGS application created a greater difference in perfusion between silicone (less perfusion) and non-silicone sites (greater perfusion) for both NS and HTS when compared to initial SGS application demonstrating a greater effect on perfusion the longer SGS was worn.