Scarring Occurs at a Critical Depth of Skin Injury: Precise Measurement in a Graduated Dermal Scratch in Human Volunteers

摘要

In this fascinating and careful study of 113 pa-1 tients, the authors study the depth of dermal injury required to produce a visibly detectable scar. An innovative device with a blade that can extend to a maximum depth of 1.6 mm was used to create a 2-inch lateral hip incision of continuous varying depth from the superficial dermis to the deep dermis. Depth measurements were determined by high-frequency ultrasound analysis. The maximum depth of injury was 1.3 mm, compared with a preinjury mean lateral thigh thickness of 1.73 mm. Experimental findings revealed a reduction in the depth of measurable scar over time, with a 0.3-mm reduction at the most superficial portion of the wound and a reduction of 0.5-mm at the deepest portion of the wound. These decreased measurements in depth corresponded to a decrease in scar width. At a calculated depth of approximately 0.5 mm, or 33 percent of the thickness of the dermis, the threshold was crossed between an absence and presence of visible scarring