I heard people use silicone sheet for reducing raised scars (i.e., keloids). I was wondering what is the rational behind it, and whether it actually works.
I cannot say the mechanism, but I can confirm it works, and can say that is generally accepted as working, not as some weird dubious treatment. I had surgery to install a rod in my leg after a broken bone. On the advice of my physical therapist, I purchased "Scar Away" brand silicone oil with roller applicator. Placing a thin layer and massaging with the applicator twice a day for four weeks turned my giant cheloids into small sections of skin which were distinguishable only by their smoothness and lack of hair, not color. He said he used to work for some basketball team and it was common practice to be used in professional basketball.
According to several papers (Sawada and Sone, 1992; Wong et al., 1996), increased hydration appears to be the main mechanism by which silicone oil acts on raised scars. Combined with an occlusive dressing, this preparation would increase hydration of the scar site. Sawada and Sone (1992) compared silicone oil treatment to vaseline treatment and found significantly improved healing with silicone oil, concluding that it was the hydrating action of silicone oil that led to improvement.
Sawada Y, Sone K. 1992. Hydration and occlusion treatment for hypertrophic scars and keloids. Br J Plast Surg 45(8):599-603.
Wong TW, Chiu HC, Chang CH, Lin LJ, Liu CC, Chen JS. 1996. Silicone cream occlusive dressing--a novel noninvasive regimen in the treatment of keloid.. Dermatology 192(4):329-33.