The bilobed flap is a double transposition flap commonly used in reconstruction of facial skin defects. The bilobed flap allows for the movement of more skin over a longer distance than that possible with a single transposition flap. This flap is especially useful when it is applied to facial areas where skin is less mobile (eg, nasal tip, temporal forehead), because it allows for reconstruction of the primary defect with skin of matching consistency and color.
History of the Procedure
In 1918, Esser first described the bilobed flap to repair nasal tip defects, as seen in the image below.  He attributed the increased versatility of the flap to the reduced arc of rotation required by using 2 flaps to reconstruct the defect instead of 1.
Zimany is generally credited with popularizing the use of the bilobed flap.  He defined this as a flap consisting of 2 lobes separated by an angle and based on a common pedicle.
The use of a bilobed flap is indicated when the tissue adjacent to a cutaneous defect is insufficiently mobile to close the defect without causing tissue distortion.
A study by Chiummariello et al indicated that in terms of nasal reconstruction following the removal of skin cancer, bilobed local flaps are a particularly good choice for repair of the dorsum and tip. In the study, which involved 107 patients, the investigators, accounting for such factors as the characteristics of tissue adjacent to the defect and of the donor skin area, as well as the presence of fixed structures, and examining the results achieved with front-glabellar, bilobed, nose-cheek, sliding, and frontal island flaps, reported the best flaps for different parts of the nose to be as follows  :
Ala: Nose-cheek flap
Dorsum: Front-glabellar flap, bilobed flap, and sliding flap (lateral region)
Tip: Frontal island flap and bilobed flap
The bilobed flap is a random transposition flap because its blood supply does not arise from a segmental artery and no defined pedicle is present.
Blood is supplied to the skin via musculocutaneous and cutaneous arteries that perforate subcutaneous tissue. These vessels ascend into the deep reticular and papillary dermis to supply deep and superficial microcirculatory plexus. Rich anastomoses of vessels within these plexus provide blood flow into the most distant portion of the flap.
For more information about the relevant anatomy, see Facial Anatomy in Cutaneous Surgery.