**Region:** Head and Neck # Facial Artery Musculomucosal (FAMM) Flap ## Anatomy - Pedicle: named artery (typical diameter/length if present), venae comitantes; course from origin to flap/skin paddle; perforator pattern (number, location, intramuscular vs septocutaneous), choke vessels/adjacent angiosomes. - Pedicle: facial artery (branch of the external carotid) running tortuously through the cheek; flap includes the facial artery throughout its length and relies on submucosal venous plexus for drainage (facial vein not routinely harvested). (Pribaz; Hanasono; Abbassi/Pribaz) - Course: facial artery hooks around lower border of mandible at anterior edge of masseter, ascends obliquely toward oral commissure then more vertically toward alar base, continues as angular artery to medial canthus. Reported anatomic positions: crosses superior border of mandible at mean 6.5 cm (range 5.3–8.2 cm) from midline and lies ~1.38 cm (range 1–1.6 cm) lateral to oral commissure at the level described. (Niranjan; Dupoirieux; Hanasono) - Perforator pattern: multiple small mucosal and cutaneous perforators from the facial artery supply anterior buccinator and mucosa; perforators are small and variable — this is the rationale for centering the flap directly on the arterial course rather than relying on single large perforators. (Neligan; Hanasono; Abbassi/Pribaz) - Venous drainage: extensive submucosal venous plexus connects to facial vein anteriorly and to pterygoid plexus/internal maxillary posteriorly; this plexus is sufficient and explains low rates of venous congestion despite absence of a named comitant vein in the flap. (Pribaz; Dupoirieux; Hanasono) - Angiosomes / choke vessels: axial perfusion along facial artery allows long narrow flap designs with high length/width ratios (reported up to 5:1); collateral connections (superior labial, inferior labial, angular, infraorbital) permit retrograde or antegrade basing. (Pribaz; Hanasono) - Nerves: sensory and motor branches relevant to flap harvest and sensate reconstruction. - Motor: buccal (deep) branches of facial nerve (VII) supply buccinator; terminal branches of facial nerve lie superficially to the artery in the cheek—maintain proper plane to avoid injury; marginal mandibular branch courses superficially near mandible and should be respected during extraoral approaches. (Abbassi/Pribaz) - Sensory: long buccal nerve (mandibular V3) provides sensation to buccal mucosa and pierces posterior superior buccinator; avoid deep injury when dissecting posterolaterally. (Abbassi/Pribaz) - Included tissues: skin/subcutaneous/fascia/muscle; thickness profile; arc of rotation; common variants/anomalies. - Included tissues: mucosa, submucosa, a cuff of buccinator muscle (and near commissure a sliver of deep orbicularis oris), facial artery with surrounding fibrofatty tissue and submucosal venous plexus. (Pribaz; Hanasono; Abbassi/Pribaz) - Thickness: average flap thickness ≈ 1 cm. (Hanasono) - Typical dimensions: commonly 1–2 cm wide; described range 1.5–2 cm; conservative maximum widths reported 2.5–3 cm to permit primary closure (some authors cite 2 × 8 cm as a commonly used maximum footprint). Lengths reported up to 7–9 cm (long axial flaps of 8–9 cm described); length/width ratios up to 5:1 feasible because of axial supply. (Pribaz; Hanasono; Abbassi/Pribaz) - Arc of rotation: pivot at gingivobuccal sulcus for superiorly based flaps; retromolar trigone for inferiorly based flaps; flap may be tunneled through gingivobuccal sulcus, passed over alveolus through edentulous gaps, or transposed posteriorly to tonsillar/floor of mouth region. Superiorly based flaps can be rotated 90° for sulcus/vermillion or up to 180° for nasal lining (tunneled to nose). (Pribaz; Hanasono; Abbassi/Pribaz) - Variants/anomalies: facial artery termination varies (angular, lateral nasal, superior labial, alar base) and course may be circuitous in a subset; preoperative Doppler mapping advised. Accessory parotid duct/gland may be present (~20%)—design anterior to Stensen’s duct to avoid it. Parotid duct measures 4–6 cm length and ~5 mm diameter where noted. (Niranjan; Frommer; Abbassi/Pribaz) ## Dissection Steps 1. Positioning, markings, landmarks. - Position: supine, table rotated to allow surgeon access; nasal endotracheal tube preferred for intraoral work (oral tube secured contralaterally acceptable). Place silk traction sutures on ipsilateral upper/lower lips and commissure to improve exposure. (Pribaz; Hanasono) - Mark: map facial artery course intraorally with a handheld Doppler (extra- and intraoral mapping recommended). Mark Stensen’s duct or keep flap anterior to it (avoid crossing over second maxillary molar). Outline flap centered on Doppler-identified artery in boomerang/oblique design; width typically 1.5–2 cm (do not exceed width that prevents primary closure; authors commonly limit to 2.5–3 cm). Mark pivot point (gingivobuccal sulcus or retromolar trigone) depending on superior vs inferior base. (Pribaz; Hanasono; Abbassi/Pribaz) 2. Plane (suprafascial/subfascial), perforator identification (handheld/IO Doppler). - Plane: intraoral dissection through mucosa → submucosa → buccinator (include small cuff of muscle). Maintain dissection plane just deep to facial artery and its accompanying tissue; do not skeletonize the artery — leave surrounding soft tissue to preserve venous plexus. (Pribaz; Hanasono; Abbassi/Pribaz) - Identification: begin distal end first. Use handheld Doppler repeatedly to confirm location of artery along flap during harvest. Identify and ligate the distal facial artery branch early to ensure entire flap remains axial. (Pribaz; Hanasono; Neligan) 3. Pedicle dissection: exposure, control, division; transfer/inset; perfusion checks. - Start at distal end: incise mucosa/submucosa/buccinator; identify facial artery in fatty layer; ligate and divide distal artery and leave a long suture to use as traction (“leash”) during proximal dissection. Confirm you have the main facial artery, not a branch. (Pribaz; Hanasono) - Elevation: score rest of flap and dissect proximally just deep to the artery, preserving a cuff of buccinator and submucosal tissues; maintain soft-tissue base near pedicle to preserve venous plexus. Use fine needle electrocautery at low settings (authors describe needle-point at ~15 watts) or sharp dissection; frequent Doppler checks to ensure arterial signal within flap. (Abbassi/Pribaz; Hanasono) - Length: develop until required length achieved; typical safe axial flap length reported 7–9 cm; avoid over-stretching/unfurling tortuous artery under tension even if additional length might be obtained—prefer tension-free inset. (Hanasono; Abbassi/Pribaz) - Transfer/inset: avoid tunneling when possible—incise mucosa between flap base and defect to inset with no tension; when tunneling to nasal floor, lateral rhinotomy incisions may be needed for inset; temporary nasal obstruction is expected until pedicle is divided. Protect pedicle from mastication (bite block may be necessary when pedicle bulk crosses dentition). (Pribaz; Hanasono; Abbassi/Pribaz) - Perfusion checks: intraoperative Doppler confirmation of arterial signal within flap; clinical check of color and bleeding of flap tip after inset. For staged procedures, pedicle division is generally performed at 2–3 weeks when neovascularization is adequate; temporary occlusion (vessel loop) can be used to test distal flap viability before division. (Hanasono; Pribaz) 4. Donor-site closure techniques. - Close donor site in two layers intraorally: reapproximate buccinator muscle (absorbable suture, e.g., 3–0 Vicryl) and mucosa (running or interrupted absorbable, e.g., 4–0 chromic gut). Keep closure anterior to Stensen’s duct to avoid ductal injury. Primary closure is usually possible for narrow flaps; wider flaps (>2–3 cm) risk mucosal tethering and may require Z-plasty later for contracture. Drains typically not required. (Hanasono; Abbassi/Pribaz) ## Indications and Contraindications - Indications: common reconstructive scenarios; size limits; need for thin vs bulky; sensate needs. - Indications: moist mucosal reconstruction of anterior/posterior hard palate, soft palate, alveolus, buccal sulcus, floor of mouth, tongue, tonsillar fossa, oral cavity lining; upper and lower lip mucosa/vermilion; nasal lining (septum, nasal floor, alar lining in staged procedures); orbital lower eyelid mucosa; select skull-base reconstructions with modifications. (Pribaz; Hanasono; Abbassi/Pribaz) - Size limits: typical flap width 1–2 cm (commonly 1–2 cm); conservative maximum width 2.5–3 cm to permit primary donor closure and avoid tethering; typical lengths reported 7–9 cm; practical clinical footprint often cited as up to ~2 × 8 cm. (Pribaz; Hanasono; Abbassi/Pribaz) - Tissue character: provides thin, mucosal, non–hair-bearing, well-vascularized tissue (average thickness ≈ 1 cm) appropriate when like-for-like mucosal replacement is preferred. (Hanasono; Abbassi/Pribaz) - Sensate reconstruction: sensory nerve preservation not primary aim; flap is not a dedicated sensate flap in usual harvest. - Contraindications: vascular disease, prior surgery/radiation (relative/absolute), comorbidity risks. - Absolute/relative: prior ligation of facial artery (e.g., during neck dissection) is a contraindication to ipsilateral inferiorly based (antegrade) FAMM unless collateral routes are proven adequate; prior scarring or incisions along planned flap course may render flap unreliable. Prior radiation is not an absolute contraindication—reports of successful use in irradiated fields exist but caution advised. (Hanasono; Abbassi/Pribaz) - Other: intact dentition may limit ability to pass a superiorly based flap through alveolar gap—choose inferiorly based or staged approaches as appropriate; poor oral hygiene or inability to comply with postoperative care increases risk. ## Postoperative Care - Monitoring schedule/method (clinical, Doppler, implantable probe), warming, antithrombotic practice, positioning/splinting, drains, mobilization, diet/analgesia. - Monitoring: clinical observation of flap color, capillary refill, bleeding from flap tip; Doppler handheld may be used perioperatively to confirm arterial signal. No standardized implantable monitoring protocol is described in the source texts. (Hanasono; Pribaz) - Oral care/diet: maintain good oral hygiene with regular mouthwashes; start soft diet and advance during first week. (Pribaz) - Analgesia/other: routine postoperative analgesia as indicated; no special anticoagulation protocols detailed in the sources. - Immobilization/protection: temporary bite block when flap crosses dentition and risk of pedicle compression/bite injury; protect pedicle from mastication until division. (Pribaz) - Suture care: remove nonabsorbable sutures by ~10 days if present; absorbable layers may persist and do not require removal. (Pribaz) - Return-to-OR thresholds and time windows. - Pedicle division: staged division typically at 2–3 weeks when flap has neovascularized; temporarily occlude pedicle with vessel loop to test viability before final division. (Hanasono; Pribaz) - Re-exploration: no explicit numeric time windows provided; use standard clinical triggers—loss of Doppler signal or persistent ischemia/congestion warrants early re-evaluation. (Sources describe clinical checks and Doppler but do not give strict time thresholds.) ## Complications (rates & management) - Venous congestion, arterial thrombosis, partial/total loss, infection, fat necrosis; include percent/frequency if present. - Reported frequencies: the provided chapters do not give quantified complication rates; qualitative statements note that venous congestion is uncommon due to robust submucosal venous plexus. (Pribaz; Dupoirieux; Hanasono) - Donor-site issues (seroma, hematoma, contour deformity, hernia/weakness) with typical frequencies when reported. - Donor-site morbidity: intraoral donor site generally closed primarily; excessive width (>2–3 cm) can cause cheek tightness/contracture sometimes requiring scar release with Z-plasties. No numeric frequencies reported. (Pribaz; Abbassi/Pribaz) - Management algorithms (re-exploration, leeching, thrombolysis): what, when, how. - General management principles from sources: - If distal flap appears ischemic intraoperatively: reassess axiality — ensure facial artery included along entire flap; avoid further proximal dissection until correct vessel is identified. - If viability uncertain before pedicle division: delay division and allow further neovascularization; test with temporary occlusion (vessel loop) before dividing at 2–3 weeks. (Hanasono) - Venous congestion: sources report this is rare; no specific leeching protocols are provided in the cited chapters. Do not skeletonize pedicle—preserve cuff of tissue to maintain venous plexus to reduce congestion risk. (Pribaz; Dupoirieux) - No specific percentages or formal thrombolysis/re-exploration algorithms are provided in the assigned texts. ## Key Clinical Pearls - Map the facial artery with a handheld Doppler (extra‑ and intraoral) and center the flap on the Doppler signal — the facial artery must traverse the entire length of the flap to avoid distal ischemia. (Pribaz; Hanasono; Neligan) - Keep the flap narrow enough for primary donor closure — commonly 1–2 cm wide; avoid routinely exceeding 2.5–3 cm to reduce risk of cheek tethering and need for later Z-plasty. (Hanasono; Abbassi/Pribaz) - Begin dissection at the distal end, identify and ligate the facial artery early, and leave a long suture on the divided artery to use as traction while elevating the remainder of the flap. (Pribaz) - Do not skeletonize the artery — preserve surrounding submucosal/fibrofatty cuff to maintain venous plexus; the flap relies on an extensive submucosal venous network rather than a single comitant vein. (Pribaz; Dupoirieux) - Use repeated intraoperative Doppler checks to confirm arterial signal in the flap during harvest and after rotation; test distal perfusion before committing to pedicle division. (Neligan; Hanasono) - Avoid tunneling when possible — incise mucosa between flap base and defect and inset without tension; when tunneling to nasal cavity expect temporary airway obstruction with superiorly based flaps until pedicle division at ~2–3 weeks. (Pribaz; Hanasono) - Protect the pedicle from mastication — use a bite block if pedicle crosses dentition or if pedicle bulk near mandible could be injured; consider mucoperiosteal trough technique to reduce need for a bite block in dentate patients. (Matros/Pribaz modification described; Abbassi/Pribaz) - Maintain proper plane to avoid injury to facial nerve terminal branches that lie directly beneath the facial artery — gentle dissection and preservation of superficial musculature safeguard facial expression. (Pribaz; Abbassi/Pribaz)