Bilobe Flaps
John A. Zitelli
INTRODUCTION
The bilobe flap is an extremely useful random pattern flap for facial reconstruction. It is a double transposition flap in which both flaps share a common base, the closure of the flap does not cause distortion of surrounding tissues, and the mechanics of the flap allow for the recruitment of redundant tissues from distant sites. The primary flap is used to repair the surgical defect while the secondary flap repairs the original flap donor site. Originally described by Esser in 1918, the bilobe flap, after modifications, has become the flap of choice for reconstruction of small- to medium-sized defects along the lower third of the nose. The original design required that the angle of tissue transfer between each lobe of the flap be 90 degrees, for a total transposition of 180 degrees. Although this design maximizes the distance that skin can be moved, the wide angles also resulted in increased wound closure tension, noticeable pincushioning (trapdoor) of the flap, and prominent tissue protrusion (dog-ears) at the pivotal points of rotation. Excision of this redundant tissue would not be feasible since it would narrow the base of the flap excessively and compromise the circulation and flap survival.
In 1989, I published significant modifications to the original flap design that minimized the risks of pincushioning and dog-ear formation. I emphasized using narrower angles of transfer of 45 degrees between each lobe, so that the total transposition of the flap occurs over no more than 90 to 110 degrees. By reducing the angle of rotation, limitations of pivotal restraint including flap shortening, increased tension of the closure, and cutaneous deformity at the pivot point of rotation were addressed (Fig. 41.1).
The bilobe flap expands the use of the traditional single transposition flap. As a double transposition flap, it transfers the tension of wound closure over a 90 degrees arc, instead of the usual 45 to 60 degrees of a single transposition flap. The addition of the second, tension-releasing lobe allows for the repair of defects that could otherwise not be closed with a single transposition flap due to wound tension and distortion of surrounding structures. This mechanical release of tension offered by the bilobe flap is identical to that of a double Z-plasty, enhancing tissue movement and transposition about the pivotal point (Fig. 41.2). With proper preoperative planning and surgical execution, the bilobe flap is not only useful for reconstruction of surgical defects on the nose, particularly the nasal tip and ala, but can also be used successfully to repair defects involving the eyelids, eyebrows, cheeks, chin, and lips.
HISTORY
Just as every surgical defect is defined by its inherent characteristics, so is each patient who harbors such an infirmity. A comprehensive medical examination is required of all patients undergoing surgery. A detailed medical history, including cardiopulmonary, endocrine, and autoimmune conditions, must be evaluated as each circumstance can compromise wound healing. Details with regard to local trauma, surgery, sun exposure, and radiation therapy are important as well. A list of current medications and allergies is required. The use of tobacco, alcohol, or substance dependence may limit postoperative wound healing
as well as postoperative therapies. Finally, medical clearance may require one or more specialist’s involvement for medical optimization prior to surgery.
as well as postoperative therapies. Finally, medical clearance may require one or more specialist’s involvement for medical optimization prior to surgery.
 FIGURE 41.1 A and B: Improved design prevents distortion of free margin and minimizes dog-ear and trap-door defects. |
PHYSICAL EXAMINATION
When developing a reconstructive plan, a defect-oriented approach is useful in the determination of what native tissues and resources exist, while also establishing which elements are absent and need to be restored. It is important to consider the quality, quantity, and medical history of the tissues surrounding the current
defect as well as the dimension of the facial aesthetic units involved. Specifically, the bilobe flap is best suited for circular defects and has multiple variations that are useful in the closure of defects along the nose as well as the eyelids, cheek, upper lip, and chin. Tissue is taken from one region to restore another. In essence, the defect is transposed to a region that is of less functional and aesthetic priority and has better reconstructive capabilities. For example, the complex anatomy and unique characteristics of the nose make it challenging when planning for reconstruction of surgical defects. Its topography is composed of multiple adjacent convex and concave surfaces that should not be distorted. The free margins of the alar rims are mobile and can be easily displaced. The skin over the lower third of the nose is thick and inelastic making it difficult to recruit for closure of surgical defects. Additionally, the color and texture of the skin is so unique that it can be difficult to match with either distant or nearby skin. Additional considerations during physical examination are as follows:
defect as well as the dimension of the facial aesthetic units involved. Specifically, the bilobe flap is best suited for circular defects and has multiple variations that are useful in the closure of defects along the nose as well as the eyelids, cheek, upper lip, and chin. Tissue is taken from one region to restore another. In essence, the defect is transposed to a region that is of less functional and aesthetic priority and has better reconstructive capabilities. For example, the complex anatomy and unique characteristics of the nose make it challenging when planning for reconstruction of surgical defects. Its topography is composed of multiple adjacent convex and concave surfaces that should not be distorted. The free margins of the alar rims are mobile and can be easily displaced. The skin over the lower third of the nose is thick and inelastic making it difficult to recruit for closure of surgical defects. Additionally, the color and texture of the skin is so unique that it can be difficult to match with either distant or nearby skin. Additional considerations during physical examination are as follows:
 FIGURE 41.2 The effect of a double Z-plasty. A: The original design. B: The double Z plasty. |
 FIGURE 41.2 (Continued) C: Lines demonstrate shortening in the horizontal plane. D: The Z-plasty actually lengthens in the vertical plane to prevent upward pull on mobile free margins. |
The eyelid margin can be easily displaced, and primary wound closure or local flaps used in this area can often result in downward traction on the eyelid. Although full-thickness skin grafts are a good reconstruction option for infraorbital surgical defects, they may not provide adequate color and texture match, and potential contraction of the graft can result in ectropion. Snap and distraction tests of the lower eyelid are critical as well as the presence of a negative vector (relation of the cornea to the orbital rim).
Challenges in the reconstruction of cheek or infraorbital defects arise when simple rotation flaps will not provide enough tissue movement for closure of moderate- to large-sized defects. This is especially true when the defect is located on the central cheek where the amount of remaining skin may not be sufficient to fill the surgical defect and still enable closure of the donor site. Additionally, considerable accentuation of the facial skeleton can occur when wounds are closed with limited tissue resources and under tension. Review of facial motion and sensation (CN V and VII) is of considerable importance.
Defects around and including the mouth may require unique solutions due to superficial loss of soft tissue, especially along the upper lip. In such circumstances, it is important to maintain oral competence and function. Once again it is important to evaluate for muscular activity, enunciation, and air wasting.
INDICATIONS
Nasal Defects
The bilobe flap is well suited for reconstruction of surgical defects on the lower third of the nose, particularly those involving the lateral tip, supratip, or ala near the tip. With minimal wound closure tension on the primary flap, there is little or no distortion when repairing defects near the alar rim. Furthermore, the use of skin adjacent to the defect provides excellent color and texture match with aesthetic results exceeding those obtained from the use of full-thickness skin grafts.
Extranasal Defects
Cheek
Bilobe flaps may be used anywhere on the cheek even though the incision lines may not follow the natural wrinkle lines on the face. The advantage of lack of wound closure tension and distortion of surrounding structures outweigh the disadvantage of the final curvilinear scar.
Chin
The bilobe flap can be used to repair large defects on the chin without distortion of the lower lip providing excellent aesthetic results. In this location, the bilobe flap uses skin from the submental and superior neck regions. The first lobe is placed adjacent to the surgical defect in the submental skin and the second lobe is placed in the anterior cervical skin. This allows excellent textural and color match, especially in men with dark terminal hair, while concealing the scars in less cosmetically noticeable locations.
Upper Lip
The cosmetic unit of the cutaneous upper lip has a very restricted surface area, making repair of surgical defects sometimes quite challenging. Most local flaps use the adjacent melolabial fold as a donor site, but movement of these flaps often results in distortion of the upper lip when repairing large defects. The bilobe flap can be used successfully for defects in the lateral upper cutaneous lip by utilizing the skin reservoir of the cheek.
Eyelids
The bilobe flap can be used to repair large surgical defects anywhere in the infraorbital region including the mid and lateral lower eyelid, as well as the medial and lateral canthus. Defects in the lateral canthus take advantage of the skin in the preauricular cheek and temple. Here, the flap can be designed with the pivot point placed caudally where the first lobe is adjacent to the defect, and the secondary lobe lies parallel to the “crow’s feet.”
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