A UNIQUE skin bank set up at the Prince of Wales Hospital less than two years ago is now helping rebuild the lives of more than 250 burns patients every year using some of the most advanced treatment available. The bank is believed to be the world's first comprehensive and multi-purpose skin bank designed to carry out three major inter-related functions. Firstly, it provides frozen pig skin or donated cadaver skin for the temporary coverage of burn wounds. But it also provides cultured skin made from human epidermal cells to cover the wound permanently, while making and processing bio-synthetic skin or human skin substitute for wound coverage. Chief of the Burns Unit at the hospital Dr Walter King Wing-keung said: ''There are many other skin banks in the world but they are generally used as depots for cadaveric skin. ''We knew that cadaveric skin would be lacking in Hong Kong and so, until we get a good supply, we use the next best alternative which is pig skin.'' So the skin bank, which opened in November 1992 as part of the hospital's burns unit, is made up of three sections housed under one roof. The cryo-storage section has a computerised programmable freezer which gradually freezes pig skin or cadaveric skin to - 196?C for long-term storage in a liquid nitrogen container. Dr King said: ''Fresh pig skin is extremely useful in promoting the healing of burn wounds while it has a long shelf life and there is an unlimited supply. ''Infected burn wounds are a major cause of death and so the pig skin is used as a protective dressing which gives the wound a better chance of permanent healing.'' The bank's cultured skin section, allows cultivation and propagation of skin cells. The combined use of fresh pig skin and cultured skin in burns' treatment in 1991 constituted a major breakthrough. Finally, the bio-synthetic skin section provides updated technology to make and process human skin substitute made from cultured skin and bovine collagen which promises to be a useful cover of burn wounds.