**Region:** Head and Neck # Paramedian Forehead Flap ## Anatomy - Pedicle: supratrochlear artery (axial artery; terminal branch of the ophthalmic artery). Venae comitantes run with the artery; small veins run parallel to the artery. - Course: arises from the ophthalmic artery within the orbit, pierces the orbital septum at the supratrochlear notch, comes around the orbital rim, then courses superiorly between the corrugator supercilii (deep) and frontalis (superficial) muscles and becomes progressively more superficial as it traverses the frontalis to run just deep to the dermis toward the hairline (can be followed to/into hairline). (Hanasono; Grabb & Smith) - Variants: flap may alternatively be based on the supraorbital or angular vessels when indicated. Avoid oblique designs that fail to include the axial supratrochlear vessel in the distal flap, which converts the distal portion to a random pattern and risks ischemia. (Hanasono; Handbook of Plastic Surgery) - Nerves: - Supratrochlear nerve accompanies the supratrochlear artery as it exits the medial orbit — important sensory structure to be recognized during pedicle dissection. (Hanasono) - Motor branches to frontalis/corrugator are deep to the flap planes; stay in correct dissection planes to avoid motor injury. - Included tissues: - Skin, subcutaneous tissue; flap thickness varies by level and can be tailored: distal third elevated subcutaneously (superficial, thinner), middle third in submuscular/subgaleal plane beneath frontalis (intermediate), inferior third in the subperiosteal plane (deeper) to protect the vessel coursing between corrugator and frontalis. (Hanasono) - Can include full‑thickness skin grafts placed on undersurface of pedicle when lining is needed. (Hanasono) - Arc of rotation: long vertical axis allows wide reach to most nasal subunits; additional length obtained by carrying flap into hairline or curving along hairline and by dissecting pedicle down to medial canthus/near orbital rim for a free pivot point. (Hanasono; Handbook) - Common variants/anomalies: - Oblique/diagonal designs that do not include the axial supratrochlear vessel reduce reliability of distal flap. (Hanasono) - Small venous tributaries and variable anastomoses with supraorbital, angular, and contralateral vessels—clinical perfusion depends on these anastomoses during staged transfer. (Handbook; Grabb & Smith) ## Dissection Steps 1. Positioning, markings, landmarks. - Supine with head stabilized. Mark midline, hairline, nasion/radix, medial canthus, course of supratrochlear vessel with a handheld Doppler (mark vessel course ipsilateral to the defect). Design template of nasal defect and transpose to forehead centered over the supratrochlear vessel; plan flap vertical along forehead to hairline (may extend into hairline if extra length needed). (Hanasono; Handbook) 2. Plane (suprafascial/subfascial), perforator identification (handheld/IO Doppler). - Do not inject local anesthetic with epinephrine into the flap itself (may mask perfusion); infiltration around flap margins (not into flap) is acceptable. Map supratrochlear vessel with Doppler preop. (Hanasono) - Elevation sequence (distal → proximal): - Distal third: raise in subcutaneous plane, preserving branches of supratrochlear vessels located just deep to dermis; trim hair bulbs if flap includes hair. - Middle third: elevate in submuscular/subgaleal plane beneath frontalis to protect axial vessel. - Inferior third: change to subperiosteal plane over the orbital rim and beneath corrugator to protect the supratrochlear vessel as it exits the orbit. Dissect proximally almost to medial canthus to gain length and free rotation. (Hanasono) 3. Pedicle dissection: exposure, control, division; transfer/inset; perfusion checks. - Protect supratrochlear artery and accompanying nerve during proximal dissection (do not skeletonize the pedicle). Mobilize to desired pivot point; test reach with a sponge/Esmarch. Inset flap to nasal defect, perform single-layer skin closure with eversion to reduce pincushioning; place deeper absorbable sutures as needed. For combined lining needs a skin graft or folded flap/lining may be used under the forehead flap (see nasal-lining techniques in Handbook). (Hanasono; Grabb & Smith; Handbook) - Staging and division: allow flap to inosculate for typically 3–4 weeks before division. Before division temporarily occlude pedicle (e.g., cinched vessel loop) to test distal perfusion; if distal flap remains pink and healthy, divide pedicle safely; if pallor/congestion persists, delay division. After division excise most of pedicle and inset base carefully to restore medial brow contour. (Hanasono) 4. Donor-site closure techniques. - Undermine forehead in subgaleal plane to temporalis bilaterally and under hair-bearing skin for maximal mobility. Primary closure commonly possible when donor defect is small; donor site may be closed primarily when defect ≤ 3 cm (if forehead laxity allows). For larger donor defects, close inferior portion primarily and allow distal areas to heal secondarily or use skin grafting; avoid letting periosteum dry on areas healing secondarily. Tissue expansion of forehead is an option preoperatively when time allows. (Hanasono; Grabb & Smith) ## Indications and Contraindications - Indications: - Large nasal skin defects (partial to total nasal resurfacing) — tip, alar, columella and subtotal/total nasal reconstruction; reconstruction requiring thin, pliable skin with excellent color/texture match; simultaneous cover and, by folding or grafting, lining options when needed. (Handbook; Grabb & Smith) - Best option when local tissues inadequate and when a staged, reliable axial flap is required. - Can be used in two- or three‑stage reconstructions; single-stage tunneled pedicle is possible but less common. (Hanasono) - Contraindications / relative limitations: - Local infection or unstable oncologic margin (prepare and clear prior to reconstruction). - Prior forehead/scalp surgery or radiation that has compromised supratrochlear vascular territory (relative). - Poor forehead skin laxity or inability to accept donor‑site scar; extremely vascular disease with poor axial perfusion (relative). - Oblique flap designs and skeletonized pedicles — technical pitfalls that reduce distal reliability (avoid). (Hanasono; Handbook) ## Postoperative Care - Monitoring schedule/method: - Clinical monitoring (color, capillary refill) is primary. Pre‑division test of perfusion by temporary pedicle occlusion (cinched loop) at 3–4 weeks to assess neovascularization; proceed to division if distal portion remains pink and healthy. (Hanasono) - Handheld Doppler may be used to check supratrochlear flow preop and intraop; no specific implantable probe protocols are provided in these sources. - Warming/antithrombotic practice: - Texts do not specify routine anticoagulation/antithrombotic regimens for paramedian forehead flap — follow institutional microsurgery protocols for free flaps if applicable. Do not inject epinephrine into flap. (Hanasono) - Positioning/splinting, drains, mobilization, diet/analgesia: - No special dressings are required beyond routine steri‑strips for small nasal procedures; for forehead flap general wound care and head elevation as tolerated. Protect pedicle from shear; avoid excessive head movement early. (Hanasono; V‑Y nasal notes) - Return-to-OR thresholds and time windows: - If, at the pedicle-division test (≈3–4 weeks), the distal flap is pale or congested → delay division and allow further vascularization; consider re-exploration only if clinical signs of arterial or venous compromise occur early (sources recommend delay rather than immediate division when questionable). (Hanasono) ## Complications (rates & management) - Complications (frequencies not specified in attached PDFs): - Venous congestion — clinical detection by bluish discoloration/slow capillary refill; management in staged flap: conservative observation, delay of pedicle division; for acute venous compromise after inset consider exploration. (Hanasono; Grabb & Smith general principles) - Arterial insufficiency/thrombosis — presents as pallor and absent capillary refill; management requires prompt exploration if early; for delayed concerns, delay pedicle division and allow further inosculation. (Hanasono) - Partial distal necrosis — more likely with oblique designs, skeletonized pedicle or smoking; management: expectant care for small areas, debridement and local revision/grafting for larger losses. (Hanasono; Grabb & Smith) - Infection, fat necrosis, contour irregularity — manage with antibiotics for infection, debridement and secondary contour revisions when mature. (general principles in sources) - Donor-site issues: - Scarring: primary closure usually possible for smaller donor defects (≤3 cm) but larger defects may require secondary healing or grafting; expanded skin may contract and deform reconstructed nasal features if not anchored. (Hanasono; Handbook) - Exposed bone/periosteum on donor site prolongs healing — avoid drying periosteum; if exposed calvarium present, may need additional intervention. (Hanasono) - Donor‑site morbidity rates not quantified in the provided texts. - Management algorithms (what/when/how): - Pedicle-division algorithm: allow flap to inosculate for 3–4 weeks → temporarily occlude pedicle (cinched loop) → if distal flap remains pink/healthy, divide pedicle and inset remainder; if pale or congested, delay division and reassess later. (Hanasono) - If early arterial/venous compromise after inset → urgent surgical exploration (anastomosis not applicable for pedicled flap) and correction of mechanical causes; for venous congestion in distal island pedicled flaps conservative measures and, if necessary and described for other nasal flaps, adjunctive measures (not specifically detailed in these texts) — do not speculate beyond provided sources. ## Key Clinical Pearls - Always mark the supratrochlear vessel preoperatively with a handheld Doppler and orient the flap vertically so the defect template is centered over that vessel; ipsilateral forehead flap is usually used. (Hanasono; Handbook) - Dissect the flap in thirds: distal third subcutaneous (preserve dermal branches), middle third submuscular/subgaleal beneath frontalis, inferior third subperiosteal as it passes the orbital rim — this sequence protects the supratrochlear vessels. (Hanasono) - Do not design oblique flaps that exclude the axial supratrochlear vessel from the distal flap — this converts the distal portion to a random pattern and increases risk of distal necrosis. (Hanasono; Handbook) - Do not inject local anesthetic with epinephrine into the flap itself — infiltrate around the flap; epinephrine masks clinical assessment of perfusion. (Hanasono) - To gain additional length safely, extend the distal flap into the hairline (hair can be trimmed or removed later) or dissect the pedicle down to the medial canthus/orbital rim for a free pivot point. (Hanasono; Handbook) - Allow the flap to revascularize before division: commonly wait about 3–4 weeks; perform a temporary pedicle occlusion (cinched vessel loop) to test distal perfusion before definitive division. Delay division if pale or congested rather than proceeding. (Hanasono) - Donor closure: undermine widely in the subgaleal plane to temporalis bilaterally and under hairline; donor site may be closed primarily for small defects (≤3 cm) but larger areas may need secondary healing or grafting — avoid letting periosteum dry. (Hanasono; Handbook)