**Region:** Lower Extremity # Lateral Thigh Flap ## Anatomy - Pedicle: - Primary arterial supply: branch of the lateral femoral circumflex artery (descending branch) that runs in the septum between vastus lateralis and rectus femoris and supplies anterolateral thigh tissues and adjacent muscles. The branch to rectus femoris typically emerges 1–2.5 cm distal to where the lateral femoral circumflex artery splits from the profunda femoris artery. Venae comitantes accompany the arterial pedicle. (source: rectus femoris chapter) - Alternative/variant origins: when extending proximally to include the anterolateral thigh or for a true gluteal-thigh design, the pedicle may be followed to its origin at the profunda femoris/lateral femoral circumflex junction; ligation of the distal lateral femoral circumflex just distal to the rectus branch can gain an additional 2–3 cm of length (at the cost of anterolateral thigh/vastus lateralis use). (source: rectus femoris chapter) - Minor pedicles: one to three small branches from the superficial femoral artery may enter the lateral thigh musculature distally; these are generally not independently sufficient to sustain a large flap. (source: rectus femoris chapter) - Pedicle length: the rectus femoris branch is described as short (major pedicle often ~2–5 cm at initial exposure) and is commonly dissected to the profunda femoris junction to gain length for rotation or free transfer. (source: Hanasono/Butler) - Course: - The lateral femoral circumflex neurovascular bundle continues inferiorly in the septum between vastus lateralis and rectus femoris to supply vastus lateralis and the overlying anterolateral skin. The descending branch exits deep to sartorius at a predictable level (level of the sartorius) and enters the deep-lateral surface of rectus femoris. Passing the flap subsartorially yields additional reach. (source: rectus femoris chapters) - Perforator pattern: - Skin/subcutaneous supply over the lateral/anterior thigh derives from branches of the lateral femoral circumflex system traversing the vastus lateralis region (musculocutaneous and septocutaneous components of the LFCA territory). When the lateral thigh is extended into a subtotal thigh flap, multiple perforators supply a large contiguous skin territory (an anterolateral thigh-type vascular territory). Minor distal superficial femoral branches may supply small distal perforators. (source: rectus femoris/subtotal thigh discussion) - Practical skin-paddle sizing guidance: a skin paddle of approximately 8–9 cm width can usually be harvested and the donor site closed primarily; skin paddles wider than about 9 cm commonly require split-thickness skin grafting. A subtotal thigh flap skin area can exceed 400 cm2. (source: Butler/Tech figs) - Choke vessels/adjacent angiosomes: - The lateral femoral circumflex axis connects to adjacent thigh angiosomes (vastus lateralis, tensor fascia lata, rectus femoris territories) permitting chimeric/subtotal designs incorporating muscle, fascia (iliotibial band), and skin. Division of distal branches (or use of AV interposition grafts) is described when additional reach is required. (source: rectus femoris chapter) - Nerves: - Motor: femoral nerve innervates rectus femoris (L4 root contribution). When rectus femoris muscle is included, the motor branch is typically divided when the flap is harvested as a nonfunctional transfer; innervated (functional) transfers have been described as a variation. (source: rectus femoris chapter) - Sensory: the intermediate femoral cutaneous nerve supplies skin over rectus femoris region. For posterior/lateral designs or gluteal-thigh extensions, the posterior femoral cutaneous nerve runs with the inferior gluteal/descending branch sheath in the posterior thigh region ~72% of the time and may be included for sensate flaps in that region (posterior thigh / gluteal-thigh flaps). (sources: rectus femoris; posterior thigh chapter) - Included tissues: - Skin, subcutaneous tissue, fascia lata/iliotibial band, vastus lateralis muscle, rectus femoris muscle, and tensor fascia lata can be incorporated singly or as chimeric components based on the lateral femoral circumflex vascular axis. The iliotibial band can be harvested for fascial reconstruction of abdominal wall defects when designing a subtotal thigh flap. (source: rectus femoris/subtotal thigh) - Thickness profile: not precisely quantified in the provided texts; thickness will vary by patient habitus and whether vastus lateralis/rectus femoris are included (muscle-added designs are bulkier; muscle-only designs may be skin grafted). (source: operative descriptions) - Arc of rotation and common variants: - Pedicled lateral/subtotal thigh flap (including rectus femoris +/- vastus lateralis +/- IT band/TFL) will reliably reach the lower abdomen, mons pubis, lateral hip, perineum and groin. A pedicled subtotal thigh flap can reach up to the level of the umbilicus. For mid-to-superior abdominal defects the flap is commonly converted to a free transfer. Variants: pedicled muscle-only, pedicled myocutaneous, pedicled subtotal thigh (chimeric), free rectus femoris/subtotal thigh, innervated rectus femoris transfer. (source: rectus femoris chapter) ## Dissection Steps 1. Positioning, markings, landmarks. - Position: supine with bilateral legs internally rotated at the hips for anterior/lateral harvest. Legs are secured at the forefoot with tape/foam to relieve pressure. (source: rectus femoris chapter) - Landmarks/markings: - Mark ASIS (anterosuperior iliac spine) and superolateral border/midpoint of patella. A line connecting ASIS to the superolateral patella approximates the lateral border of rectus femoris; a line from midpoint of the patella to ASIS is the central axis of the rectus femoris muscle. (source: rectus femoris / Hanasono) - If planning a skin paddle, center an elliptical skin island directly over the muscle/anticipated perforators; plan width ≤ 8–9 cm for a design likely to allow primary closure. For subtotal thigh flaps, transpose a defect template onto the thigh. (source: rectus femoris chapter) - Two‑incision minimally invasive option: a short distal incision 6–8 cm long directly over the rectus femoris at the distal thigh to allow disinsertion from the patella, and a separate proximal incision over the major pedicle region to perform proximal dissection and tunneling. For muscle-only harvest, make the distal incision 4–6 cm proximal to the patella. (source: rectus femoris / Hanasono) 2. Plane (suprafascial/subfascial), perforator identification (handheld/IO Doppler). - Initial skin incision and dissection through subcutaneous tissue to deep fascia overlying muscle belly; blunt dissection frees medial and deep surfaces of rectus femoris. Laterally/distally the plane between rectus femoris and vastus lateralis is often ill-defined and requires sharp/electrocautery dissection. (source: Hanasono/Butler) - If including a cutaneous paddle, suture skin edges to muscle fascia after initial elevation to prevent shear. A handheld Doppler may be used in planning to localize perforators when designing a skin paddle (especially for gracilis/ALT-type perforators; applied analogously for lateral thigh planning in the texts). (sources: rectus femoris; gracilis) 3. Pedicle dissection: exposure, control, division; transfer/inset; perfusion checks. - Distal tendon disinsertion: disinsert distal rectus femoris from the patella, leaving 2–3 cm of tendon attached to assist in inset suturing. (source: Hanasono) - Proximal dissection: free the muscle from medial/lateral/deep attachments; clip/ligate minor vessels from superficial femoral system encountered along deep surface. A lighted retractor aids proximal dissection. (source: rectus femoris) - Identify sartorius crossing obliquely; the main pedicle enters deep and lateral at the level of the sartorius. Divide the motor nerve to the muscle if a nonfunctional transfer is planned. (source: rectus femoris) - Pedicle skeletonization: the initial visible pedicle length may be ~2–5 cm; dissect proximally to the junction with the profunda femoris artery to gain additional length for free transfer or to improve rotational freedom for pedicled transfer. Passing the flap deep to the sartorius (subsartorial transposition) provides approximately 5 cm additional advancement. (sources: Hanasono; rectus femoris chapter) - For subtotal thigh flap including vastus lateralis/anterolateral thigh skin, the proximal dissection is carried to the LFCA–profunda branch point. If free transfer is required and the pedicle is short, options described include transecting the rectus branch at its emergence to preserve ALT/vastus lateralis or ligating the distal LFCA distal to the rectus takeoff to gain 2–3 cm (with trade-offs noted). (source: rectus femoris chapter) - Transfer/inset: as a pedicled flap inset into groin/perineum/abdomen, the flap can be tunneled or passed under sartorius; for buried muscle-only coverage, muscle can be inset and overlying skin closed or skin grafted. For subtotal flaps requiring extensive skin, donor site often needs split-thickness skin grafting. (source: rectus femoris chapters) - Free flap adjunct: if recipient vessels are distant or unavailable (e.g., deep inferior epigastric system absent), a saphenous vein arteriovenous loop may be created: transect distal saphenous vein, leave proximal intact, anastomose distal saphenous end-to-side to superficial femoral artery, position loop adjacent to flap pedicle, divide at apex to provide arterial and venous vein grafts. (source: rectus femoris chapter) - Perfusion checks: standard clinical assessment after inset (capillary refill, color) is described; no specific implantable monitoring protocols are detailed in these texts. 4. Donor-site closure techniques. - Quadriceps tendon reconstruction: approximate vastus lateralis tendon to vastus medialis tendon with buried permanent sutures (typically no. 1 polypropylene) to centralize the remaining quadriceps moment arm. Tenorrhaphy is commonly extended 10–15 cm proximally. This repair minimizes donor-site morbidity and loss of terminal knee extension. (source: rectus femoris chapter) - Skin closure: - For skin paddles ≤ ~8–9 cm width primary closure is generally achievable. - For flaps wider than ≈9 cm or subtotal thigh flaps with large skin area, split-thickness skin grafting of the donor site is frequently required. (source: rectus femoris / tech fig captions) - Drains and layers: close soft tissues in layers over one or two drains as needed; for large/subtotal flaps donor sites typically have drains and often skin graft management. (source: rectus femoris / subtotal thigh) ## Indications and Contraindications - Indications: - Pedicled lateral/subtotal thigh flap (including rectus femoris/myocutaneous variants): coverage of large full‑thickness abdominal wall defects (lower abdomen, mons), groin, perineum, lateral hip, and pelvic outlet; subtotal thigh flaps used for massive anterior abdominal wall surface area reconstruction (unilateral or bilateral). (source: rectus femoris chapter) - Free lateral/subtotal thigh transfer: reconstruction of mid/superior abdominal wall, chest, and head & neck when pedicle length and recipient vessels allow. (source: Hanasono/Butler) - Chimeric designs: when both fascial (iliotibial band) and skin/muscle components are required (eg, abdominal wall with combined mesh + fascial repair). (source: rectus femoris chapter) - Need for thin vs bulky: choose muscle-only (buried) or myocutaneous/skin-paddle designs depending on need for bulk or skin coverage; subtotal/thicker designs include vastus lateralis and are bulkier. (source: rectus femoris) - Size limits: - Skin paddle width ~8–9 cm allows primary closure in many patients; flaps wider than ~9 cm often require skin grafting. Subtotal thigh flap skin area can exceed 400 cm2. (source: rectus femoris) - Contraindications: - Known peripheral vascular disease affecting the lateral femoral circumflex system (CT angiography recommended when vascular disease suspected). (source: rectus femoris) - Prior surgeries that have transected the lateral circumflex/proximal pedicle (eg prior large gluteal or anterolateral thigh harvests) that compromise the pedicle — such prior procedures should be anticipated and assessed. (source: posterior/gluteal thigh chapters) - Relative considerations: patient comorbidities that impair wound healing (smoking, uncontrolled diabetes, immobility) should be optimized preoperatively. (sources: posterior thigh; general preop notes) ## Postoperative Care - Monitoring schedule/method: - Clinical monitoring (color, turgor, capillary refill) is used; specific continuous doppler or implantable monitor protocols are not detailed in the provided texts. Drains are commonly left beneath the flap/donor site. (sources: multiple operative descriptions) - Warming/positioning: - Keep donor lower extremity elevated when not ambulating. For rectus femoris harvest, immobilize knee in extension with a knee immobilizer postoperatively (see immobilizer duration below). (source: rectus femoris) - Antithrombotic practice: - Specific anticoagulation regimens are not detailed in the provided excerpts. - Positioning/splinting: - After rectus femoris-based harvest, place patient in a knee immobilizer in extension. One recommendation: immobilizer worn for 6 weeks (first source); another describes a splint/immobilizer for 3–6 weeks — immobilizer use and subsequent formal physical therapy are advised. (sources: Butler; Hanasono) - Drains, mobilization, diet/analgesia: - Drains under flap/donor site are commonly used and removed per standard drain criteria. Early ambulation is encouraged: ambulation as early as postoperative day 1 with weight bearing as tolerated after rectus femoris harvest. Analgesia/diet follow institutional norms. (source: rectus femoris chapter) - Return-to-OR thresholds and time windows: - Specific numeric thresholds and time windows for return to the OR for vascular compromise are not specified in the provided texts; standard practice is clinical concern for ischemia or venous congestion to prompt urgent re-exploration. ## Complications (rates & management) - Flap survival and skin complications: - Muscle-only rectus femoris flap: flap loss rate described as negligible in the cited series for muscle flaps. (source: rectus femoris chapter) - When elevated as a subtotal thigh/myocutaneous flap there is an observed 2% rate of distal tip skin necrosis. (source: rectus femoris chapter) - Donor-site complications and frequencies: - Published donor-site wound separation rate: 3–4%. Donor-site hematoma has a similar reported rate (3–4%). (source: rectus femoris chapter) - Functional donor-site morbidity: quantitative study reported unchanged knee range of motion but decreased extension power by 10.3% (concentric contraction) and 19.3% (eccentric contraction) after rectus femoris harvest. Other authors have reported no loss of knee extension in select series. (sources: rectus femoris chapter; Hanasono) - Posterior/gluteal-thigh complications: - Specific complication rates for posterior/gluteal thigh flaps are not numerically provided; cautions include potential venous drainage compromise if full dissection is performed without leaving venous bridges, and concern for prior flap harvests transecting descending branches. (sources: posterior thigh / gluteal thigh) - Management algorithms: - Prevention of donor-site functional morbidity: perform robust quadriceps tenorrhaphy (vastus lateralis to vastus medialis) with buried permanent sutures and immobilize knee postoperatively; engage formal physical therapy for strength and ROM (described as effective to mitigate strength loss). (source: rectus femoris) - Donor closure options: primary closure for flap widths usually <9 cm; if wider, plan split‑thickness skin grafting. (source: rectus femoris) - For large abdominal reconstructions when local recipient vessels unavailable, described solution is saphenous vein arteriovenous loop creation to enable free transfer. (source: rectus femoris) - Specific rescue strategies for arterial or venous thrombosis, leech therapy, thrombolysis, or re-exploration timing are not detailed in the provided PDFs and therefore are not included. ## Key Clinical Pearls - Internally rotate the legs at the hip during marking and harvest to reliably identify the rectus femoris axis (ASIS to superolateral patella represents lateral border; midpoint patella to ASIS is central axis). (source: rectus femoris) - The major rectus femoris pedicle (branch of LFCA) typically emerges 1–2.5 cm distal to the LFCA–profunda branching point and enters the muscle on its deep and lateral surface at the level of the sartorius. Expect to find the pedicle deep/lateral. (source: rectus femoris) - Passing the flap deep to the sartorius (subsartorial transposition) buys approximately 5 cm of additional advancement — essential for pedicled reach to lower abdomen/groin. (source: rectus femoris) - Skin paddles ≈8–9 cm wide are usually closable primarily; paddles wider than ≈9 cm commonly require split-thickness skin grafting of the donor site. Plan skin paddle width accordingly. (source: rectus femoris) - The lateral femoral circumflex vascular axis can be used in chimeric fashion (rectus femoris + vastus lateralis + anterolateral thigh skin + iliotibial band/tensor fascia lata) for massive surface area/fascial reconstructions (subtotal thigh flap; skin area >400 cm2 described). (source: rectus femoris) - The pedicle is relatively short; if a free transfer is required consider proximal dissection to the profunda femoris junction, ligation of distal LFCA for an extra 2–3 cm, or plan for vein-graft/AV-loop strategies if recipient vessels are distant. (source: rectus femoris) - Reconstruct the quadriceps tendon complex thoroughly: approximate vastus lateralis to vastus medialis with buried permanent sutures and extend tenorrhaphy 10–15 cm proximally when needed — this reduces risk of loss of terminal knee extension. Immobilize the knee postoperatively (commonly 6 weeks recommended; some series describe 3–6 weeks) and institute targeted physical therapy. (sources: rectus femoris; Hanasono) - Expect low overall flap loss for muscle-only designs; donor-site wound complications (separation, hematoma) were reported in the 3–4% range, and distal tip necrosis for subtotal myocutaneous designs ~2% in series cited — counsel patients accordingly. (source: rectus femoris)