Buccinator myomucosal flap - Vula - University of Cape Town

OPEN ACCESS ATLAS OF OTOLARYNGOLOGY, HEAD &NECK OPERATIVE SURGERYBUCCINATOR MYOMUCOSAL FLAPThe Buccinator Myomucosal Flap is anaxial flap, based on the facial and/or buccalarteries. It is a flexible and versatile flapwell suited to reconstructing soft tissuedefects of the oral cavity, oropharynx andnasal septum. Unlike most free flaps, itprovides mucosal cover, as opposed to skincover, and is sensate. The donor site canusually be closed primarily withoutcausing deformity or scarring. The flap isabout 5mm thick, and comprises buccalmucosa, submucosa and buccinatormuscle, with the feeding vessels andvascular plexus.Johan FaganThe buccal artery is a branch of theinternal maxillary artery and supplies theposterior half of the muscle. It coursesanteroinferiorly under the lateral pterygoidmuscle to reach the posterior half of themuscle, where it anastomoses with theposterior buccal branch of the facial artery.Relevant AnatomyBuccinator muscleThe buccinator muscle is a thin,quadrilateral muscle in the cheek. Itoriginates from the outer surfaces of thealveolar processes of the maxilla andmandible. Posteriorly it arises from thepterygomandibular raphe. Anteriorly itinserts into the orbicularis oris muscle.Laterally it is related to the ramus of themandible, the masseter and medialpterygoid muscles, the buccal fat pad andthe buccopharyngeal fascia. Medially, it iscovered by the submucosa and mucosa ofthe cheek. It is part of the pharyngealbuccal-orbicularissphincter system andfunctions to facilitate whistling, sucking,propelling food during mastication andvoiding the buccal cavity.Blood supply (Figure 1)The buccal, facial and posterosuperioralveolar arteries provide the main bloodsupply to the muscle. These arteries forman extensive vascular anastomotic plexuson the lateral surface of the muscle andwithin its fibres.Figure 1: Blood supply of buccinatormuscle, demonstrating vascular plexusThe facial artery hooks around theinferior margin of the mandible at theanterior edge of the masseter muscle, andsupplies numerous branches to thebuccinator muscle, the largest of which isthe posterior buccal artery that supplies theposterior half of the muscle. The facialartery also gives off 1-3 inferior buccalbranches to supply the inferior half of themuscle, and then continues in ananterosuperior direction to give off 3-5small, anterior buccal branches to theanterior half of the muscle. Theposterosuperior alveolar artery is abranch of the internal maxillary artery andprovides 2 small branches that enter themuscle posterosuperiorly. The infraorbitalartery gives off a few small brancheswhich enter it anterosuperiorly. Venousdrainage occurs via the pterygoid plexus

and internal maxillary vein. It liesposterior, superior and superficial to thebuccinator muscle and drains into thebuccal vein via the deep facial vein.Anteriorly, the deep facial vein drains intothe facial vein proper.elevated, generally in an anterior toposterior direction. The flap is elevated inthe loose areolar plane between thebuccinator muscle and thebuccopharyngeal fascia.InnervationMucosal sensory innervation is by thelong buccal nerve, a branch of themaxillary division of the trigeminal nerve,which courses with the buccal branch ofthe internal maxillary artery. Motorinnervation of the buccinator muscle isvia the temporal and cervical divisions ofthe facial nerve laterally in the buccal fatpad.Parotid ductThe duct pierces the buccinator muscleopposite the 2 nd upper molar, slightlyabove the center of the muscle, and shouldbe identified and preserved when raisingthe flap.Elevation of flapA flap as large as 7x5cm may be raised.The extent is limited by the parotid ductposterosuperiorly, the oral commissureanteriorly and the pterygomandibular rapheposteriorly. It may be based posteriorly(buccal artery), or anteriorly (facialartery) or superiorly (facial artery).Although not essential, a handheld Dopplercan be used to map out the facial arteryand the buccal artery before raising theflap (Figure 2). If a Doppler is not used,then care has to be taken to place the initialincisions so as not to separate the vesselsfrom the flap.The buccal mucosa and the buccinatormuscle are incised to the level of thebuccopharyngeal fascia, and the flapFigure 2: Vessels mapped out withhandheld Doppler probeThe artery that the flap will be based on isidentified, and dissection proceedsbetween the artery and thebuccopharyngeal fascia, directed towardsthe origin of the vascular pedicle, keepingthe vessel in full view, using dissectingscissors (Figures 3, 4). Preservation of thebuccopharyngeal fascia prevents herniationof buccal fat and avoids injury to branchesof the facial nerve. Minor bleeding vesselsare coagulated with bipolar electrocautery.Figure 3: Flap elevation commences afteridentifying artery (Black arrow)2

is ligated and divided superiorly. Thedissection continues in a plane lateral tothe vessels, as the flap is raised from frontto-back,and from superiorly-to-inferiorly.Superiorly Based Buccinator FlapThis is a reversed-flow flap based on thefacial artery and its anterior buccalbranches (Figure 9).Figure 6: Flap for anterior floor of mouthFigure 9: Blood supply of superiorly basedbuccinator flapFigure 7: Blood supply of anteriorly basedbuccinator flapThe flap is then elevated in a superiordirection. It can be used for soft tissuedefects of the hard palate and superioralveolus (Figure 10), including oroantraland oronasal fistulae, as well as for nasalnasal septal defects.Figure 8: Preserved facial artery in Level1The mucosa and the buccinator muscle areincised just posterior (approx 1cm) to thecommissure of the mouth, and the facialartery is identified in the cheek. The arteryFigure 10: Superiorly based flap forsuperior alveolectomy defect4

Dissection is commenced at the inferiormargin of the flap, where the facial arteryis identified and ligated.Benefits of buccinator flapThe buccinator flap is a versatile flap thatcan be used to reconstruct a variety ofdefects. It is very reliable, simple andquick to raise, replaces mucosa withmucosa, is sensate, and has very littledonor site morbidity. It is remarkablyelastic and malleable, and can be stretchedto conform to complexly shaped defectsand is an excellent alternative to radial freeforearm flaps for reconstruction of smalland moderate sized defects of the oralcavity and oropharynx (Figures 11 a, b, c).Figure 11a: Defect following anterolateralfloor of mouth resection andmarginal mandibulectomyUseful referenceVan Lierop A, Fagan JJ. Buccinatormyomucosal flap: Clinical results andreview of anatomy, surgical technique andapplications. J Laryngol Otol, 2008; 122:181-7Author & EditorJohan Fagan MBChB, FCORL, MMedProfessor and ChairmanDivision of OtolaryngologyUniversity of Cape TownCape Town, South Africajohannes.fagan@uct.ac.zaFigure 11 b: Anteriorly based buccinatorflapTHE OPEN ACCESS ATLAS OFOTOLARYNGOLOGY, HEAD &NECK OPERATIVE SURGERYwww.entdev.uct.ac.za/index_files/Page650.htmThe Open Access Atlas of Otolaryngology, Head &Neck Operative Surgery by Johan Fagan (Editor)johannes.fagan@uct.ac.za is licensed under a CreativeCommons Attribution-NonCommercial 3.0 UnportedLicenseFigure 11 c: Inset of flap5