The effect of silicone gel sheets on perfusion of hypertrophic burn scars

The mechanism of action of topical silicone gel sheets on hypertrophic scars is not well understood and their effect on the blood flow within hypertrophic scars has not been investigated. The purpose of this study was to examine whether application of silicone gel sheets produced any acute effects on blood flow in hypertrophic burn scars. Perfusion of hypertrophic scars and adjacent normal skin was measured using a laser Doppler with and without application of silicone gel sheets. Continuous measurements were made for 5 minutes before gel application, for 30 minutes during gel application and for 5 minutes following gel removal. Surface temperature of the scar was continuously monitored. An occupational therapist, blinded to the perfusion level, rated each scar using the Vancouver Scar Scale. Eighteen scars and adjacent control sites in sixteen adult burn patients (11 male, 5 female; mean age: 42 +/- 14 years) were evaluated. The mean scar age was 5.4 +/- 3.7 months. The mean Vancouver Scar Scale was 5.5 +/- 2.4. Hypertrophic scars demonstrated higher perfusion measurements at baseline compared to control areas (58.5 +/- 19.3 flux units vs 25.0 +/- 8.4 flux units; P < 0.001). Application of silicone sheeting gel did not significantly alter perfusion in either the hypertrophic scar or normal tissue from the baseline measurements. However, application of silicone gel sheeting did significantly increase the mean baseline surface temperature of the hypertrophic scar from 29 +/- 0.8 degrees C to 30.7 +/- 0.6 degrees C (P < 0.001). The mechanism of action of silicone gel sheeting probably does not involve an acute alteration in blood flow within the scar. However, surface temperature of the scar increased significantly following gel application, raising the possibility that temperature alteration is involved in the mechanism of action.