Large septal perforations (≥ 2 cm)
Septal perforation in patients with poor quality or lack of intranasal tissues such as those with previous radiation therapy in the concerned area, extensive ablative surgeries, or chronic cocaine abuse
18.3.1 Facial Artery Pedicle
The facial artery follows a cervical course after exiting the external carotid artery. It crosses the submandibular gland and reaches the inferior border of the mandible at the anterior limit of the masseter muscle. The facial artery travels in the cheek lateral to the buccinator muscle and the levator anguli oris, while remaining medial to the risorius, zygomaticus major, and the superficial layer of the orbicularis oris muscle. 18, 19 The artery has a very tortuous trajectory on its way to the internal canthus to form the angular artery. Through this latter we can expect a retrograde flow from the ophthalmic artery, which originates from the internal carotid artery system. 20
The facial artery is located approximately 16 mm from the labial commissure. It sends off perforators of the jugal area and branches to give the superior labial artery among others. Several branching variations and terminal endings of the facial artery have previously been described. 21 The classification by Lohn et al includes 22 type I = angular, type II = lateral nasal, type III = alar, type IV = superior labial, type V = inferior labial, and type VI = undetected.
The facial vein usually runs posteriorly and in close proximity to the facial artery at the level of the mandible. It progressively diverges from the artery as it reaches the nose. Doppler flow studies have shown an average distance between the two vessels of 13.6 mm at the oral commissure and 16.3 mm under the alar base. 23 The vein begins at the internal canthus as the angular vein and runs along the nasogenian fold to become the facial vein.
18.3.2 Facial Artery Musculomucosal Flap
The FAMM flap is an intraoral cheek flap and includes the buccal mucosa, submucosa, buccinator muscle, and superficial layer of the orbicularis oris muscle ( ▶ Fig. 18.1). Superiorly based flaps are used for nasal septum perforations to maximize tissue length. Superiorly based FAMM flaps are pedicled on the angular artery and perfusion occurs through a retrograde flow. The facial artery is preserved on the entire length for the flap and kept attached to the buccinator muscle ( ▶ Fig. 18.2). The facial vein is usually not included in the flap as venous drainage is assured by a submucosal plexus. 24 The pivot point of flap is in the vicinity of the maxillary tuberosity or in the gingivolabial sulcus. The average width of the flap is 2.5 to 3 cm, and the pedicle base should be at least 1.5 cm to ensure adequate venous drainage. 17
Fig. 18.1 Schematic illustration of the FAMM flap in a coronal cut through the cheek. (1) Mucosa and submucosa; (2) buccinator muscle; (3) facial artery; (4) motor branches of the facial nerve; (5) mimic facial muscles; (6) superior gingivobuccal sulcus; (7) molar; (8) maxilla; (9) incision and plane of dissection of the FAMM flap (interrupted line).
Fig. 18.2 Example of a facial artery preserved on the entire length of the FAMM flap. *, course of the facial artery.
18.4 Surgical Technique
The FAMM flap was first described by Pribaz et al in 1992 16 as a versatile musculomucosal flap harvested intraorally in the area of the jugal mucosa. It can be pedicled either inferiorly on the facial artery or superiorly on the angular artery. For the reconstruction of intranasal defects, a superiorly based pedicled FAMM flap will be harvested.
Antimicrobial prophylaxis directed against oral cavity flora is recommended. After oral intubation, the endotracheal tube is positioned contralateral to the surgical bed. It can be held in place with transjugal or intraoral dental sutures. Neuromuscular-blockage will facilitate exposure of the oral cavity throughout the procedure. We do not recommend local infiltration of the flap outline with an epinephrine solution as it can provoke a spasm of the facial artery that may hinder its dissection.
18.4.2 Drawing the Flap
The buccal mucosa is exposed using two traction sutures in the upper and lower lips and a Weider’s tongue retractor (heart-shaped). Alternatively, Senn’s retractors or Gillies skink hooks can be used instead of traction sutures. With the anatomical landmarks in mind, an outline of the flap is drawn on the buccal mucosa ( ▶ Table 18.1). The anterior limit of the flap lays 1 cm posterior to the labial commissure to avoid its distortion after closure of the defect. The posterior limit of the flap lies just anterior to Stensen’s duct papillae. A distance of 0.5 to 1 cm is preserved between the posterior margin of the flap and the gingiva to facilitate wound closure ( ▶ Fig. 18.3). The use of a Doppler to identify the facial artery has been previously described 3 but will hardly ever modify the flap outline, as it relies on fixed anatomical landmarks. Moreover, the facial artery course outline is not reliable anymore after the mucosal incision because the mucosa becomes loose. Superiorly, the flap base is designed to hinge at the junction between the gingivolabial sulcus and first molar.
Anterior limit (1 cm from the commissure)
Lateral (superficial) wall of the artery defines the depth of the dissection plane
Y junction between facial and superior labial arteries
Superior labial artery can be identified first and dissected backward to identify the facial artery
Fig. 18.3 Flap design with anatomical landmarks. (1) A distance of 1 cm is preserved between the anterior portion of the flap and the labial commissure; (2) Stensen’s duct papillae is visualized posteriorly to the flap; (3) the distal portion of the flap is pointing toward the gingivolabial sulcus; (4) a minimal width of 1.5 cm is conserved at the base of the flap; (5) a distance of 0.5 to 1 cm is preserved between the posterior margin of the flap and the gingiva to facilitate wound closure.
The distal end of the flap is designed according to the size and shape of the septal perforation. Measurement of the defect or usage of a template is mandatory and will allow an optimal flap outline. As the width of the FAMM flap is limited by the aforementioned landmarks (usually ~3 cm), the size and axis of the defect will decide whether the flap’s inset will be horizontal or vertical. For a long craniocaudal perforation, the flap’s inset will be horizontal, whereas a tall-vertical perforation will be covered with the flap inserted vertically.
18.4.3 Facial Artery Identification
The facial artery can be identified with two techniques. First, it can be located with careful blunt dissection at the distal end of the flap ( ▶ Fig. 18.4). Alternatively, the superior labial artery will be identified first with an incision in the area of the labial commissure and then traced back in a retrograde manner to the facial artery. It is only when the facial artery is identified that the superior labial artery is ligated.
Fig. 18.4 Superiorly based FAMM flap. The distal portion of the flap is designed to hinge at the junction between the gingivolabial sulcus and the first molar. (1) Facial artery; (2) superior labial artery.
18.4.4 Flap Harvest
The mucosal incisions are completed according to the previously drawn outline and extend through the mucosa, submucosa, and buccinator muscle. The flap is harvested in a plane deep to the facial artery. The facial artery must be kept attached to the overlying buccinator muscle over its entire length throughout the dissection (see ▶ Fig. 18.1). The facial artery is dissected in a retrograde manner, from distal to proximal. This warrants meticulous dissection as the artery is tortuous and collateral vessels will need to be clipped. As previously mentioned, the facial vein is not included as venous drainage relies on the submucosal plexus.
18.4.5 Distal Flap Preparation
The FAMM flap is fully dissected up to its base, at the junction of the gingivolabial sulcus and first molar ( ▶ Fig. 18.5). The distal end of the flap now has a mucosal side and a muscular side (buccinator muscle). The muscular side has to be covered with a full-thickness postauricular or supraclavicular skin graft prior to the flap inset ( ▶ Fig. 18.6a) The size of the skin graft is based on a template of the septal perforation size and shape. It is attached to the muscular side of the FAMM flap with a running absorbable suture. A raw muscular surface must be preserved at the perimeter of the flap to allow optimal healing against the septal perforation edges ( ▶ Fig. 18.7b).
Fig. 18.5 Front view of the oral cavity (left). *, facial artery is identified at the distal portion of the flap (resting on a blue paper).