One-stage inferiorly based transposition dorsum/lateral nasal flap in nasal ala reconstruction

Abstract

Reconstructing the nasal ala is an aesthetically complex task that depends on whether the free margin is involved, as well as the size, height, and thickness of the defect. One key aspect of reconstructing defects in this location is to avoid erasing the alar groove, the concave curved line that extends from the lateral nasal tip and merges with the alar-facial sulcus and base, completing the perimeter of the ala.¹ Loss of the alar groove and blunting of the nasofacial sulcus are major cosmetic complications in nasal ala reconstruction.² Compromise of the nasal valve is another potential functional complication. Involvement of the ala, including the alar rim, often necessitates multistage reconstruction, such as a staged interpolated paramedian forehead flap with cartilage graft support.³ Other commonly used reconstructive options include the melolabial interpolated flap⁴ (superiorly based nasolabial flap) and the inferiorly based interpolated paranasal flap.^{5, 6} These techniques require multiple interventions and single-stage reconstructive options are scarce.

We describe nine patients with partial or full-thickness nasal alar defects repaired with a one-stage inferiorly based transposition dorsum flap.

We conducted a retrospective review of Mohs micrographic surgical defects of the nasal ala repaired with an inferiorly based transposition nasal flap obtained from the dorsum and lateral nasal adjacent skin between January 2020 and June 2024 at the Department of Dermatology, University Clinic of Navarra.

The flap is designed on the nasal dorsum or lateral sidewall, with width, length, and transposition angle determined by the defect's size and location, aiming to reconstruct or accentuate the alar groove (Figures 1, 2). Depending on the defect and the morphology of the patient's nose, the movement ranges from a maximum transposition of 90° when the flap is drawn directly on the nasal dorsum, to 30° when the flap is designed on the lateral nasal side. The flap is raised in a supraperiosteal-perichondral plane until reaching the domal area, then turned down to repair the alar defect. The dissecting plane includes the superficial muscular aponeurotic system (SMAS) within the flap (Figure 3c). The nasal SMAS is located immediately superficial to the periosteum and perichondrium and includes the nasal musculature.

The pivot point “dog ear” is corrected, when necessary, by de-epithelialization and suturing of the skin. Additionally, a Limberg-type transposition flap can be designed on the excess tissue in the subcutaneous plane to reconstruct the soft triangle (Figure 3d). Often, the transposition flap covers only part of the defect and is used to reconstruct the alar groove and rim; for closure of the remaining defect or donor area, skin can be moved from the nasofacial sulcus and cheek using a secondary advancement, rotation, or transposition flap (Figures 2, 3).

A total of nine patients were included, ages ranged from 42 to 81 years. Tumor sizes ranged from 2 to 5.4 cm². Five patients had sidewall and alar defects, and four had involvement of the alar margin, with four of them presenting full-thickness defects. In the latter cases, cartilage transplants were considered unnecessary. A 90° transposition was performed in two patients, 60–75° in three patients, and 30–45° in four patients. All procedures were performed under local anesthesia. In full-thickness defects, Merocel^® dressing was applied for 24–48 hours. These full-thickness defects do not require internal lining reconstruction, as the mucosa heals rapidly by secondary intention (Figures 2, 3). Dressings with mupirocin were applied three times a day until complete epithelialization of the nasal vestibule.

Complications occurred in three patients. One experienced partial necrosis of the flap's corner, and two had minor alar retraction. The outcomes were cosmetically and functionally satisfactory in all cases, with no other post-operative complications or tumor recurrence observed after 6 months of follow-up.

We used a one-stage inferiorly based transposition dorsum flap to transfer skin from the dorsum, lateral nasal sidewall, and nasal tip to the alar defect (Figure 4). The rich vascular supply of the nose, combined with the depth of the musculocutaneous flap, has enabled us to safely use smaller pedicles and larger flaps.⁷

The inferiorly based transposition dorsum flap prevents deformation of the alar facial groove. The movement of the tissue provides structural rigidity in the domal area (its pivot point), allowing the skin to settle into the defect as an arch, recreating a natural nasal ala. Pontes et al.⁸ described a nasal dorsum transposition flap for closure of an alar rim defect. Later, Moscatiello et al.⁹ reported the results of a nasal vascular anatomical study in cadavers and described their experience in nasal alar reconstruction of ten patients using the inferiorly based dorsum nasal flap nourished by the nasal septal branches.

The ideal defect for this flap is a medium to large-sized defect, including full thickness, within the alar subunit. The closer to the free margin (alar rim), the better, as this approach avoids a visible scar, leaving only the alar groove scar. As the turnover dorsal nasal flap includes the epidermis, dermis, subcutaneous fat, and SMAS, it is quite stiff, reducing the risk of nostril collapse without the need for cartilage in full-thickness defects. In full-thickness defects, the mucosa healed by second intention within a few days and did not cause any inconvenience such as bleeding or pain.

A classic method for nasal ala reconstruction involves a lobed transposition flap using the nasolabial sulcus or cheek as a donor site.¹⁰ This often results in asymmetry and bulging of the nasal ala, with loss of the alar groove. The advantages of the inferiorly based transposition dorsum flap include excellent cosmetic outcomes regarding contour, matching skin color and texture, preservation of the alar facial groove, minimal risk of noticeable cheek asymmetry, absence of hair transfer, and generally lower morbidity compared to traditional cheek and forehead interpolation flaps. The procedure is straightforward and can be performed in a single stage under local anesthesia.

None.