Ths use of medical-grade silicone gel sheets to help prevent scar formation was pioneered in the 1980s. They can be used to help prevent scars from injuries and burns etc, as well as from surgery,

The gel sheets are worn over the damaged area for a few months, and clinical trials (as well as first hand practical experience) has shown them to be very effective at preventing scar formation.

It's not clear how the treatment works. Theories include the possibility that the sheets increase moisture retention, or that they stabilise temperature, or carry out some kind of 'signalling' function to the re-growing tissue.

More info at Wikipedia