Bilobed Flaps 

Updated: Jan 29, 2021
Author: Anthony P Sclafani, MD; Chief Editor: Arlen D Meyers, MD, MBA 

Overview

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.

Bilobed flap design, as Esser described. Bilobed flap design, as Esser described.

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] :

  • Ala: Nose-cheek flap

  • Dorsum: Front-glabellar flap, bilobed flap, and sliding flap (lateral region)

  • 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.

 

Treatment

Surgical Therapy

The bilobed flap, as Esser first described, comprises 2 flaps identical in size and form and separated by angles of 90°, as seen in the image below. Skin is transposed over 180°. This transposition commonly results in a noticeable pincushion effect or trapdoor deformity, ie, domelike elevation or depression, respectively, of the flap relative to the surrounding skin. Esser's design, shown below, results in prominent tissue protrusion (ie, dog-ear or standing cone) at the point of rotation.

Bilobed flap design, as Esser described. Bilobed flap design, as Esser described.

Modification of Esser's design, as seen in the image below, has improved cosmetic results. In modified designs, the lobes are not identical in size. The larger flap is slightly narrower than the defect it has to fill, and the second flap is half the width of the larger flap. Their lengths are identical. Angles between the lobes are less than 90°. The second flap is often designed with an elliptical tip to facilitate closure of its resulting defect. Each flap is transposed over 45°. Wide undermining is used to reduce tension and pincushion effect.

Modified design of the bilobed flap. Modified design of the bilobed flap.

The images below show a bilobed rotational flap procedure performed on a cadaveric specimen.

Bilobed flap procedure performed on a cadaveric sp Bilobed flap procedure performed on a cadaveric specimen.
Bilobed flap procedure performed on cadaveric spec Bilobed flap procedure performed on cadaveric specimen with the first (or A) flap rotated into the defect.
Bilobed flap procedure performed on cadaveric spec 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.
Photograph shows a bilobed flap procedure performe Photograph shows a bilobed flap procedure performed on a cadaveric specimen. Both lobes have been sutured in place; standing-cone deformities are shown.

Intraoperative Details

As with all local flap designs, take care to place incisions in relaxed skin tension lines. Raise the flap just deep to the subdermal plexus, leaving a small amount of subdermal fat on the undersurface of the flap. Position flaps in areas of increased tissue laxity.

Postoperative Details

Scar dermabrasion can be used after surgery, as in many reconstructive efforts, to improve the cosmetic result.

Follow-up

Remove permanent cutaneous sutures 5-7 days after surgery.

Complications

Bilobed flaps are extremely reliable when used properly. Given proper flap design, partial or complete failure is unpredictable. Flaps designed with large length-to-width ratios increase the likelihood of distal compromise because of the limited ability of the microcirculation to adequately perfuse the distal flap. Thinner flaps tend to increase the risk of distal failure because thinning the flap and leaving insufficient adipose tissue can disrupt the deep microcirculatory plexus. Because thinning may be necessary to improve the cosmetic result (ie, to avoid a pincushion effect), judicious use is recommended.

Typically, dog-ears occur when flap lobes are transposed. Moy et al described several useful ways to deal with this problem.[8] A Burow triangle may be included in the flap design at the base of the defect, as seen in the image below.

Dog-ear repair after transposition of tissues in t Dog-ear repair after transposition of tissues in the bilobed flap

Two other methods can be used to repair dog-ear defects. Excess tissue can be excised from the flap base, or it may be excised from the skin adjacent to the flap. Some believe that the cosmetic result is superior when tissue is excised adjacent to the flap because it breaks up the long, inferior scar line.

Future and Controversies

Traditionally, bilobed flaps have been used in facial reconstructive surgery to repair defects of the lower third of the nose, including defects of the nasal ala, supratip, and nasal tip. The procedure can be designed with medially or laterally based flaps. Flaps based laterally on the sidewall of the nose are most useful for the reconstruction of nasal tip defects, whereas medially based flaps are more useful for repairing alar defects.

In nasal reconstruction, bilobed flaps are most practical for defects less than 1.5 cm in diameter. Larger defects can pose a problem because of the limited ability to recruit lax donor skin from the upper nose. The bilobed flap can replace other common flaps in reconstructing the lower third of the nose.

Although median and paramedian forehead flaps provide good skin color and texture, they require multiple procedures and revisions. The nasolabial flap also provides a good match, but it has limitations in reaching the nasal tip area, and it can distort the alar contour.

Zitelli reviewed 400 cases of bilobed flaps in lower-third nasal reconstructions.[9] He found that use of a 45° angle between flaps resulted in less of a pincushion effect, trapdoor deformity, and dog-ear formation. Zitelli recommends wide undermining and dermabrasion 6 weeks after surgery if needed.

A study by Grieco et al found that nasal reconstruction with the modified Zitelli bilobed flap produced good aesthetic results and preserved function, with no reported infections or major complications. Although 12 of the study’s 86 patients (14%) experienced small alar rim distortions, these individuals still considered the procedure to have produced a good cosmetic outcome.[10]

A retrospective study by Okland et al indicated that thinning a bilobed flap through removal of excess subcutaneous tissue can minimize the rate of poor aesthetic results, revision surgery, and pincushioning, in nasal reconstruction procedures. The investigators found that overall, 20 of the 125 patients in the study (16%) had reported complications, including scarring, pincushioning, and nasal obstruction. Revision surgery was performed in five patients (4%), while four patients (3.2%) reportedly experienced pincushioning. Univariate and multivariate logistic regression analysis revealed no statistically significant correlation between defect size and the occurrence of complications.[11]

Bilobed flaps are frequently used for repairing defects of the temporal forehead. Primary closure and other local flaps can distort the eyebrow, scalp hairline, and lateral canthus of the eye. Use of the bilobed flap corresponds to the "Robin Hood principle," ie, borrowing from the rich laxity of the cheek and transposing it to the relatively poor inelastic temporal forehead without distortion.