**Region:** Head and Neck # Submental Flap ## Anatomy - Pedicle: submental branch of the facial artery with small venae comitantes; principal venous drainage of the submental region usually via a separate submental vein draining to the anterior facial vein rather than a single vena comitans (Submental Artery Perforator Flap, Neligan & Morris). The submental artery arises from the facial artery and gives perforators to the overlying skin and subcutaneous tissue of the submental/upper neck region. - Course: facial artery → submental branch → perforators that run anterior or posterior to the anterior belly of digastric to reach the skin paddle. The submental artery is identified at the superior incision during harvest and is followed proximally to the facial artery (Submental Artery Perforator Flap). - Venae: small venae comitantes accompany the submental artery but may be insufficient for flap drainage; an independent submental vein to the anterior facial vein is frequently present and variable in location—failure to include this vein is a common cause of postoperative venous congestion (Submental Artery Perforator Flap). - Perforator pattern: skin supplied by multiple small submental perforators; typical perforators run on either side of the anterior belly of digastric (two dominant perforators described anatomically) and may be musculocutaneous as they pierce or run adjacent to digastric and platysma (Submental Artery Perforator Flap). - Adjacent angiosomes/choke vessels: flap perfusion relies on the submental/facial arterial axis and the rich anastomoses of the facial artery system; venous drainage exploits pterygoid/facial plexuses and the independent submental vein where present (Submental Artery Perforator Flap). - Nerves: - Motor: marginal mandibular branch of the facial nerve runs in the operative field; it must be identified and preserved to avoid depressor weakness of the lower lip (Submental Artery Perforator Flap). - Sensory: cutaneous sensation in the submental region is via cervical branches of the cervical plexus and facial sensory branches; harvest rarely requires nerve sacrifice for routine skin paddles but identify marginal mandibular nerve to prevent motor deficit. - Included tissues: - Typical flap composition: skin, subcutaneous fat, with optional small cuff of platysma and, on the pedicle side, partial or entire anterior belly of digastric if chosen to protect perforators. - Thickness profile: variable according to patient adiposity; can be somewhat thick in obese patients and thinner in elderly with lax neck skin. Pinch-test determines maximal harvest width compatible with primary closure (Submental Artery Perforator Flap). - Arc of rotation: as a pedicled flap reaches lower to midface readily; with modifications (retrograde or extended venous lengthening) can reach upper face/forehead or intraoral sites; can also be used as a free flap for more distant defects (Submental Artery Perforator Flap). - Variants/anomalies: - submental vein position is variable and not always immediately adjacent to the artery—must be sought and included with the flap when present (Submental Artery Perforator Flap). - anatomy of the anterior belly of digastric varies; some surgeons include the muscle on the pedicle side to preserve perforators and protect them during dissection (Submental Artery Perforator Flap). ## Dissection Steps 1. Positioning, markings, landmarks. - Position: supine with neck slightly extended to expose the submental crease and jawline. - Mark flap design: flap may extend angle-to-angle of the mandible; determine maximal width by pinch test (donor-site primary closure). Mark known surface course of the facial artery if desired; identify submental crease and level of marginal mandibular nerve course as anatomic guide (Submental Artery Perforator Flap). - Plan pedicle side (ipsilateral to defect or preferred donor side) and whether flap will be pedicled or harvested as free tissue. 2. Plane (suprafascial/subfascial), perforator identification. - Superior incision first. Incise through skin and subcutaneous tissue to just superficial to platysma/SMAS depending on surgeon preference. - Dissect distally first to expose and identify the submental perforators and the submental artery at its origin from the facial artery. Identify and protect marginal mandibular nerve (see Step 3) (Submental Artery Perforator Flap). - Perforator identification methods: direct dissection with loupe/microscope; handheld Doppler may be used pre‑incision to locate dominant perforators, but definitive identification is by visualizing the artery and its perforators. - Harvest plane: raise skin/subcutaneous paddle including a thin cuff of platysma; on the pedicle side include a narrow cuff of anterior digastric if chosen to protect the perforators (many authors harvest a portion of the anterior belly on the pedicled/proximal side to reliably include perforators) (Submental Artery Perforator Flap). 3. Pedicle dissection: exposure, control, division; transfer/inset; perfusion checks. - Begin dissection on the pedicle side to identify facial artery → submental branch and the submental vein. Identify and preserve marginal mandibular nerve superficial to the facial vessels (Submental Artery Perforator Flap). - Skeletonize the submental pedicle by dissecting from pedicle toward the distal skin paddle, maintaining the artery with its perforators and taking only minimal venae comitantes (they are small). Ensure the independent submental vein (if present) is preserved and included with flap when feasible. - If additional pedicle length is needed: divide the facial artery and vein as they cross the mandible and dissect proximally—this maneuver can yield approximately 1–2 cm extra pedicle length (Submental Artery Perforator Flap). For further venous length, a Y–V venous pedicle lengthening technique may provide up to ~5 cm additional venous length (Submental Artery Perforator Flap). - Retrograde option: the submental flap can be based in a retrograde fashion on the distal facial artery (retrograde submental flap) when required to reach more cephalad defects; note that retrograde pedicled flaps may require microvascular venous anastomosis at the recipient site to secure venous outflow (Submental Artery Perforator Flap). - Division: if pedicled, leave the pedicle intact and tunnel or rotate flap to defect; verify absence of kinking or compression of pedicle—pay special attention to facial vein tightness across the mandible or within a tunnel. - Perfusion checks: clinical checks (capillary refill, colour, turgor), handheld Doppler over pedicle; if venous congestion suspected, prepare for early intervention (see Complications). - Transfer/inset: inset the skin paddle in defect with layered closure; donor site closed primarily when possible (pinch test pre-determined width). 4. Donor-site closure techniques. - Close in layers, approximating platysma/SMAS and skin; excise redundant tissue or adjust Burow triangles as necessary to avoid dog-ears. - Scar lies in the submental crease and is generally well concealed, especially in older patients with lax neck skin (Submental Artery Perforator Flap). - If primary closure under tension would be excessive, consider limiting flap width or skin advancement maneuvers. ## Indications and Contraindications - Indications: - Facial reconstruction of lower/midface defects where colour/texture match is required (cheek, perioral, alar, lip inset when appropriate). - Pedicled coverage of lower-to-midface defects; with modifications can reach upper face/forehead and intraoral sites. - Can be used as a free flap for small-to-moderate facial and scalp defects when a thin, well-matched skin paddle is desired. - Composite variants: may include segmental mandible (submental arterial branch supplies periosteum/bone) or submental lymph nodes for vascularized lymph node transfer (VLNT) when indicated (Submental Artery Perforator Flap). - Useful donor site in older patients with lax neck skin; hidden donor scar. - Contraindications / relative limitations: - Heavy submental adiposity may make flap too bulky for some facial sites. - Prior neck surgery, irradiation, or scarring that has disrupted the facial/submental vessels or submental vein may preclude safe harvest or increase complication risk. - Oncologic caution: floor-of-mouth cancers drain to submental nodes—use of submental flap in oral cancer reconstruction is controversial when there is a risk of occult nodal metastasis; weigh oncologic risk (some series report safety; others caution) (Submental Artery Perforator Flap). - Hair-bearing submental skin in male patients may contraindicate flap for non-hair-bearing reconstructions. ## Postoperative Care - Monitoring: - Clinical monitoring (colour, turgor, capillary refill, temperature) at frequent intervals in first 24–48 hours. - Handheld Doppler over the arterial pedicle checks perfusion if used intraoperatively. - For free transfers or retrograde pedicled flaps with venous concern, consider implantable Doppler or hourly checks in immediate postoperative period (institutional practice varies) (Submental Artery Perforator Flap principles). - Warming: keep head/neck warm to avoid vasospasm; avoid external compression over the pedicle/tunnel. - Antithrombotic practice: institution-dependent; standard DVT prophylaxis and antiplatelet/anticoagulation per microvascular protocols when flap is free or venous anastomosis performed. - Positioning: head elevated to reduce venous congestion; avoid neck flexion that might kink pedicle. - Drains: place subcutaneous drains at donor site if significant dead space; remove when output low. - Mobilization/diet/analgesia: early mobilization as tolerated, soft diet if intraoral inset, standard analgesia and wound care. - Return-to-OR thresholds and windows: - Immediate re-exploration indicated for suspected arterial occlusion (absent Doppler signal, hard signs of ischemia) — best chance to salvage within first 6–12 hours. - Venous congestion: early return to OR for exploration and attempt to identify/repair venous outflow if within the early postoperative window; if re-exploration not feasible or delayed, leech therapy may temporize superficial venous congestion (Submental Artery Perforator Flap guidelines). - Delayed salvage for partial distal necrosis may be managed with debridement and local revision. ## Complications (rates & management) - Venous congestion (most characteristic risk when only venae comitantes included or main submental vein omitted). - Frequency: described as a known and significant risk when the main submental vein is not included; specific numeric rates are not provided in the source. Presentation: dusky, swollen flap with slow capillary refill. - Management: immediate return to OR for venous exploration and inclusion/anastomosis of a suitable vein if available; if re-exploration cannot promptly restore drainage, medicinal leech therapy is an established temporizing measure until neovascularization occurs (illustrated case leeched with eventual recovery) (Submental Artery Perforator Flap). - Arterial insufficiency / thrombosis: - Presentation: pale, cold flap, absent Doppler arterial signal. - Management: urgent re-exploration and revision of arterial supply; salvage window best early (hours). - Partial or total flap loss: - Frequency: not numerically specified in the chapter; risk increases when venous drainage is inadequate or pedicle compromised. - Management: debridement, local/regional/free-tissue alternatives for reconstruction. - Infection, fat necrosis: standard wound care, antibiotics for established infections, debridement for necrosis. - Donor-site morbidity: - Contour irregularity, scarring concealed in submental crease; seroma/hematoma risk managed with drains and pressure dressing. - Marginal mandibular nerve injury — possible temporary or, if injured, longer-term lower lip depressor weakness; prevention by early identification and protection during pedicle dissection; management includes observation for neuropraxia, revision if iatrogenic transection. - Specific salvage algorithms (from the chapter): - If venous congestion suspected → urgent exploration to identify and include the independent submental vein (if missed), revise pedicle/tunnel, or perform additional venous anastomosis in free/retrograde settings. If immediate revascularization is not possible → leech therapy as a temporizing measure while planning revision (Submental Artery Perforator Flap). - If arterial thrombosis suspected → immediate re-exploration and arterial revision/anastomosis. ## Key Clinical Pearls - Always identify and preserve the marginal mandibular branch of VII at the start of dissection; actively visualize it to avoid iatrogenic paresis (Submental Artery Perforator Flap). - Do not rely solely on the tiny venae comitantes for venous outflow; search for and include the independent submental vein draining to the anterior facial vein whenever possible—failure to do so is the commonest cause of significant congestion (Submental Artery Perforator Flap). - Start dissection on the pedicle side first to identify the facial → submental vessels; leave a long leash on the artery as an aid in dissection and to center the flap on its vascular supply (technique principle described in chapter). - If extra pedicle length is required, dividing the facial artery/vein at the mandible and dissecting proximally can yield approximately 1–2 cm additional pedicle length (Submental Artery Perforator Flap). - For substantial additional venous length, consider a Y–V venous lengthening procedure: this has been reported to add up to about 5 cm of venous length and can extend flap reach (Submental Artery Perforator Flap). - Consider including part or all of the anterior belly of digastric on the pedicle side to protect perforators — this reliably preserves perforators but is optional depending on anatomy and defect requirements (Submental Artery Perforator Flap). - When using the flap in oncologic oral cavity reconstruction, discuss the controversy about harvesting submental tissue in the presence of potential nodal spread (drainage of floor of mouth to submental nodes); plan neck management accordingly (Submental Artery Perforator Flap). - For retrograde pedicled submental flaps (distal facial artery inflow) be prepared to perform a venous microvascular anastomosis at the recipient site if venous outflow is inadequate.