Background
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. [1, 2]
History of the Procedure
In 1918, Esser first described the bilobed flap to repair nasal tip defects, as seen in the image below. [3] 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. [4] He defined this as a flap consisting of 2 lobes separated by an angle and based on a common pedicle.
Indications
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 [5] :
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Ala: Nose-cheek flap
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Dorsum: Front-glabellar flap, bilobed flap, and sliding flap (lateral region)
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Tip: Frontal island flap and bilobed flap
A retrospective study by Knackstedt et al on cutaneous nasal reconstructive surgery indicated that, while bilobed flaps are employed more frequently than trilobed flaps in repairing the inferior nasal dorsum and sidewall, trilobed flaps are more often used distally, including at the nasal trip and infratip. [6]
Mourad et al described the successful use of medially and laterally based giant bilobed flaps for the closure of large head and neck defects, in place of skin grafts, free tissue transfers, or the employment of tissue expanders. [7]
Relevant Anatomy
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.
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Bilobed flap design, as Esser described.
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Modified design of the bilobed flap.
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Bilobed flap procedure performed on a cadaveric specimen.
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Bilobed flap procedure performed on cadaveric specimen with the first (or A) flap rotated into the defect.
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Bilobed flap procedure performed on cadaveric specimen. The first (or A) flap has been transposed into the original defect. The second (or B) flap has been transposed into the first defect.
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Photograph shows a bilobed flap procedure performed on a cadaveric specimen. Both lobes have been sutured in place; standing-cone deformities are shown.
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Dog-ear repair after transposition of tissues in the bilobed flap
