Need. The skin position where the dilator is injected with water for five months needs nutrition after injection. Expander is a unique and advanced treatment method in plastic surgery. The principle is that the skin and soft tissue expander is implanted under the normal skin and soft tissue near the lesion, and liquid is intermittently injected into the expansion sac to increase the capacity of the expander and make it exert pressure on the skin and soft tissue on the body surface.