Flap (surgery)

Flap surgery is a technique in plastic and reconstructive surgery where any type of tissue is lifted from a donor site and moved to a recipient site with an intact blood supply. This is similar to but different from a graft, which does not have an intact blood supply and therefore relies on growth of new blood vessels. This is done to fill a defect such as a wound resulting from injury or surgery when the remaining tissue is unable to support a graft, or to rebuild more complex anatomic structures such as breast or jaw.

Anatomy

The skin can be divided into 3 main layers including the epidermis, the dermis, and the subcutaneous tissue. Blood is supplied to the skin mainly by two networks of blood vessels. The deep network lies between the dermis and the subcutaneous tissue, while the shallow network lies within the papillary layer of the dermis. The epidermis is supplied by diffusion from this shallow network and both networks are supplied by collaterals, and by perforating arteries that bring blood from deeper layers either between muscles (septocutaneous perforators) or through muscles (musculocutaneous perforators). This redundant and robust blood supply is important in flap surgery because part of the supply will be cut off. The remaining blood supply must then keep the tissue alive until a more optimal supply can be restored through angiogenesis.