Reconstructive plastic surgery is performed to correct functional impairments caused by cancer or tumours; traumatic injuries, such as facial bone fractures and soft tissue lacerations and breaks; congenital abnormalities, such as cleft palates or cleft lips; developmental abnormalities; infection and disease; and burns. Reconstructive plastic surgery is usually performed to improve function, but it may be done to approximate a normal appearance. Reconstructive surgery is performed to restore form and function through techniques that include skin grafting, use of skin and muscle flaps, bone grafting, tissue expansion, free tissue transfer with microsurgery and replantation.