Epithelial Turn-in Flap for Nasal Lining Reconstruction

INTRODUCTION Full-thickness nasal defects pose a unique challenge for the reconstructive surgeon, as all layers of the nose must be addressed: the skin, the support, and the lining. Early attempts at nasal reconstruction focused on external resurfacing, which led to results marred by contracture.1,2 Thanks to the efforts of Menick and Millard, the importance of nasal lining reconstruction is now widely recognized.1,2 Addressing the internal lining helps to prevent tissue contracture, cartilage necrosis and aesthetic deformity.3 Current options for nasal lining reconstruction range from skin grafts to free tissue transfer.1,4,5 Skin grafts can be placed intranasally when the wound bed is small (less than 1.5 cm) and vascularized.1,3,5 Composite grafts may be used to provide simultaneous lining and support. However, grafts will inevitably contract, so if the wound is near the alar rim, this method will lead to visible deformity.3,5 A pedicled flap, typically a forehead flap, can be folded onto itself distally to line the nostril rim, but poor visualization during inset and tissue stiffness makes precise positioning difficult.5 Folding of the most distal aspect of the flap may also compromise vascularity.3,4 Furthermore, the resultant rim often appears bulky and requires further revision.3 Intranasal mucosal flaps provide highly vascular, thin, physiologic tissue for lining reconstruction. However, they are technically challenging to raise, cause significant intranasal morbidity (ie, septal perforation, airway narrowing), may be unavailable due to trauma, and are limited in size.3–5 Free tissue transfer, such as radial forearm free flap, is another option, but the distant donor-site scar is not appealing to many patients. Additionally, poor color and texture match to facial skin requires the external surface to be replaced with a forehead flap.4,5 The epithelial turn-in flap is not a new concept. First described by Keegan in the 1900s,2,4 the turn-in flap is an underutilized option in lining reconstruction that is reliable and reproducible. Residual dorsal nasal skin abutting the wound is elevated and “turned in” 180 degrees to create a flap based on an inferior subcutaneous pedicle. This method recreates the lining without causing additional morbidity by utilizing skin that might otherwise be discarded during remnant subunit excision.2–4 The flap is noncontractile and vascularized, providing a robust surface for cartilage grafts if additional support is needed.2 These flaps are best for defects along the alar rim involving 50% or more of the subunit, which based on the subunit principle, would warrant complete excision of the subunit for optimal aesthetic outcomes. However, rather than discarding the adjacent tissue, this tissue can be repurposed for lining reconstruction. The resultant external defect from harvesting the turn-in flap can be covered by a regional flap.1 The turn-in flap may not be the best option when the flap donor site has questionable perfusion or significant fragility, such as a site with history of radiation or skin graft. Although described in the literature, detailed step-by-step footage of the turn-in flap is lacking, making it difficult for new surgeons to replicate. Careful planning and dissection are crucial due to the flap’s location within the injury zone. CASE In the accompanying video, we describe the case of an otherwise healthy 38-year-old woman who underwent nasal reconstruction using the epithelial turn-in flap. The patient previously underwent bilateral levator labii superioris and nasalis myectomy for gummy smile. Her post-operative course was complicated by severe scarring and infection requiring multiple nasal revisions over the course of 2 years. She subsequently developed skin necrosis resulting in a full-thickness defect of her right ala. In this video, we demonstrate our technique for nasal lining reconstruction using the epithelial turn-in flap in conjunction with external resurfacing using a paramedian forehead flap. (See Video [online], which displays the use of the epithelial turn-in flap for nasal lining reconstruction.) {"href":"Single Video Player","role":"media-player-id","content-type":"play-in-place","position":"float","orientation":"portrait","label":"Video 1.","caption":"Technique video demonstrating the use of the epithelial turn-in flap for nasal lining reconstruction.","object-id":[{"pub-id-type":"doi","id":""},{"pub-id-type":"other","content-type":"media-stream-id","id":"1_s7um6xw7"},{"pub-id-type":"other","content-type":"media-source","id":"Kaltura"}]} TECHNIQUE Preoperative Planning Assess the defect: ensure that the defect involves over 50% of the aesthetic subunit. Design the flap: outline the turn-in flap along the borders of the remaining alar subunit. Keep the base (inferior edge) of the flap as wide as possible for adequate perfusion. Flap Elevation Cephalic border dissection: begin elevating the flap at the cephalic border in the immediately subdermal plane. Caudal progression: proceed caudally, increasing the flap thickness by moving into the subcutaneous plane to maintain vascularity. Cease dissection once the flap can be turned in 180 degrees so the epithelium faces intranasally. Flap Inset Trim the flap: adjust the free edges of the flap to match the contralateral nostril rim size. Inset the flap: position the flap precisely to avoid excess redundancy or tension. Optional cartilage placement: if needed, place cartilage on the raw surface of the flap for additional rim support. Note that in patients with thick nasal soft tissue, cartilaginous support is typically unnecessary. External Soft-tissue Coverage Resurface with a forehead flap: elevate and inset a paramedian forehead flap in standard fashion to cover the external nasal defect. Pedicle division: divide the forehead flap pedicle 4 weeks postoperatively. RESULTS By 3 months after surgery, the patient’s incisions were well healed. Her reconstructed nasal lining appeared viable and healthy, although mildly bulky and contracted, likely due to scarring in the donor site preoperatively. The forehead flap provided good coverage and contour for her external nasal ala. One year after her initial surgery, she underwent revision with external flap re-elevation, debulking, and transposition of the lateral portion of the flap into the nasal sill. Four weeks after revision, she demonstrated improved alar symmetry and contour as well as resolution of alar notching. She will undergo further revision in the coming months to correct her upper lip asymmetry. COMMENTS The epithelial turn-in flap provides thin, reliable tissue for nasal lining reconstruction. Major disadvantages cited by critics of this flap include bulk, nasal obstruction, and desquamation.2 In our case, the patient did present with flap bulkiness postoperatively. However, that was partially due to scarring in the flap donor site from her prior operations. The decision to utilize the epithelial turn-in flap from the scarred site was made jointly with the patient, who did not desire additional donor-site morbidity for the reconstruction of her nasal lining. If supple tissues are used for the turn-in flap, the flap can be thinned more aggressively and bulk is less of an issue postoperatively. Furthermore, as seen from our post-revision results, flap debulking, scar revision and flap transposition are all effective ways of improving the final aesthetic outcome and can easily be done in a second stage under local anesthesia. None of our patients experienced nasal obstruction, desquamation, crusting or malodor. We agree with the theory that keratinized epithelium, when transposed into an environment humidified by mucous secretions, may undergo metaplasia into respiratory epithelium.2 Of note, the presence of external epithelial skin in the nasal cavity does warrant close intranasal follow-up given the risk of actinic injury and malignant transformation.2,3 In conclusion, the turn-in flap is ideal for lining reconstruction of full-thickness defects extending to the alar rim involving over 50% of the alar subunit. The flap is a resourceful and reliable way of repurposing otherwise discarded tissue for the reconstruction of nasal lining without additional donor site morbidity.2 DISCLOSURE The authors have no financial interest to declare in relation to the content of this article.