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Anterolateral Thigh Flap

last modified on: Wed, 01/31/2018 - 12:55


Anterolateral Thigh Flap

return to: Microvascular Surgery Protocols

    1. Indications
      1. The thigh flap provides a tremendously versatile soft tissue flap. In selected patients, the skin paddle is as thin and pliable as in a radial forearm flap, with the advantage of dense fascia lata on its deep surface. The skin paddle can be made much larger than a radial forearm flap, and donor site morbidity is very low.
    2. Contraindications
      1. See General microvascular protocol. The major contraindication for the anterolateral thigh flap is obesity, which can result in unacceptable flap bulk. In addition, transmuscular perforator dissection is often required. Severe peripheral vascular disease may rarely render the flap pedicle critical to leg perfusion, making harvest unwise.
    3. Pertinent Anatomy
      1. The anterolateral thigh flap is a fasciocutaneous flap based on the septocutaneous or musculocutaneous perforators of the descending branch of the lateral circumflex femoral artery. A satisfactory perforator is generally found within 3 cm of the midpoint of a line connecting the anterior superior iliac spine with the superolateral border of the patella. More than half of perforators traverse the substance of the vastus lateralis muscle. The descending branch of the lateral circumflex femoral artery, and its vena comitans, lies between the vastus lateralis and rectus femoris muscles, along with the nerve to the vastus lateralis. The descending branch can usually be safely dissected proximally to its major branch to the rectus femoris, which should be preserved during flap harvest.
        Skin paddles can be 20 cm in length. Primary closure is possible for paddles 8-9 cm in width. In most cases, the fascia lata represents the deep aspect of the harvested flap, but suprafascial harvest is possible. Portions of vastus lateralis muscle can be harvested with the flap if necessary. The position of the nerve to vastus lateralis is variable with respect to the vascular pedicle, and the nerve cannot always be left intact during harvest. It is likely that nerve division will result in morbidity.


    1. Evaluation
      1. Exclude previous traumatic or surgical trauma to the donor site through history and careful physical exam.
      2. We do not usually obtain vascular studies.
    2. Potential Complications
      1. See General microvascular protocol. There is usually very little donor site morbidity related to the anterolateral thigh flap. Division of the nerve to vastus lateralis may result in knee instability or persistent gait disturbance.
    3. Obtaining Consent
      1. As with any case, the importance of discussing all the benefits, risks and potential side effects/long term sequelae cannot be overemphasized. In the case of a free flap, it is imperative that the unfortunate possibility that the flap may fail be discussed. Alternative measures in the best interest of the patient should be thoroughly thought out and accounted for by the physician (i.e., alternative flap (RFFF)).
    1. Room Setup
      1. See Free Flap Room Setup
      2. The room should be warmed prior to the patient's entry to maintain normothermia during anesthesia induction and positioning.
    2. Instrumentation and Equipment
      1. Standard
        1. Major Instrument Tray 1, Otolaryngology
        2. Major Instrument Tray 2, Otolaryngology
        3. Bipolar Forceps Trays
        4. Microsurgery Instrument Tray, Otolaryngology
    3. Medications (specific to nursing)
      1. Heparin sodium injection, 1,000 units per ml, 10 ml vial
      2. Papaverine injection, 60 mg per 2 ml, 2-ml ampule
      3. PhysioSol irrigation solution, 500 ml (be sure the PhysioSol is in the warmer in sufficient time to be warm when the surgeon requests it)
    4. Prep and Drape (click for photos Prep and Drape Anterolateral Thigh Free Flap)
      1. Standard prep, 10% providone iodine
      2. Drape
        1. Prepare the head and neck separately
        2. The patient should be supine. A small roll may be used under the ipsilateral hip, but is not required.
        3. Prepare the operative leg to include the anterior superior iliac spine and the patella
        4. Towels (stapled) to expose the anterolateral thigh, as far laterally as possible
        5. Split sheet
    5. Drains and Dressings
      1. Suction drain under flap: 10 mm
    6. Special Considerations
      1. Heparin sodium injection 5,000 units in sodium chloride 0.9% 500 ml in syringe, Luer tip 5 cc syringe with 24-gauge IV cannula is used to irrigate vessels.
      2. Papaverine 60 mg in 500 cc sodium chloride 0.9% in a Luer tip 10 cc syringe with 18-gauge IV cannula will be used topically to irrigate for vasospasm.
      3. Use all measures to keep body temperature at least 37.6° (warming blanket, room temperature).
    1. General
      1. Positioning: Table will be turned 180°.
      2. Peripherals: No IV or arterial lines in flap leg. The anesthesia tubing must not be placed along the body on the flap side.
      3. Prep: The anterior and lateral surfaces of the thigh, including the hip and the knee.
    2. Specific
      1. No IV, blood draw, blood pressure cuff or other monitoring devices on flap leg
      2. See General microvascular protocol
    1. Find the midpoint of a line drawn between the anterior superior iliac crest and the superolateral border of the patella. Use a handheld Doppler probe to identify a cutaneous perforator, located within 3 cm of the midpoint. Additional perforators may be present proximally.
    2. Design an elliptical flap centered at the main perforator. Skin paddle width should be based on the defect. The length should be sufficient to obtain closure without standing cutaneous deformities - excess skin can be easily trimmed during inset.
    3. The medial side of the skin paddle is incised, with a proximal extension toward the anterior superior iliac spine. The incision is taken down to the fascia lata, and then the fascia is incised. The recognition of the rectus femoris is critical, and is sometimes difficult in debilitated patients. It is identified by its bipennate morphology ("chevron pointing up"). The fascia is raised off the rectus femoris, taking care to identify the cutaneous perforators which are visualized through the fascia. The rectus femoris is then retracted medially to expose the descending branch of the lateral circumflex femoral artery.
    4. The course of the cutaneous perforator is then assessed, and additional perforators can be identified. The nerve to vastus lateralis is identified.
    5. If the perforators are musculocutaneous, they should be uncovered at this stage, to their junction with the descending branch of the lateral circumflex femoral vessels. This is accomplished by meticulous dissection with fine scissors and bipolar cautery. Circumferential dissection should not be performed at this stage.
    6. When all perforators have been uncovered, the lateral skin incision is made and carried through the fascia lata. Working from inferior to superior, the fascia lata (and skin paddle) is dissected off the underlying vastus lateralis until the inferior-most perforator is reached. This perforator is then released from its surrounding muscle, again using meticulous dissection and small vascular clips.
    7. If a single perforator is to be used, a small amount of muscle should be left adherent to it, in order to allow identification of twisting of the pedicle. This is not necessary if two perforators are included in the flap.
    8. The remaining perforators are released in the same manner as the first. Perfusion through the perforators should be verified by checking for bleeding at the cut skin edges of the flap. It is imperative that the flap/pedicle not be placed under torsion or the pedicle occluded during the harvest. 
    9. The descending branch of the lateral circumflex femoral artery and vein are then dissected superiorly to their branches to the rectus femoris, which should be preserved. The pedicle is then divided.
    10. Closure is performed by undermining medially and laterally in the suprafascial plane. No effort should be made to reapproximate the fascia lata. A 10mm suction drain should be placed, exiting superiorly. The skin is closed in two layers, with 2-0 Vicryl in the dermis followed by running 4-0 Nylon.
    1. See General microvascular protocol
    2. Keep leg elevated while supine and in chair. Weight bearing should not be restricted.
    1. Wei FC, Jain V, Celik N, Chen HC, Chuang DC, Lin CH. Have we found an ideal soft-tissue flap? An experience with 672 anterolateral thigh flaps. Plast Reconstr Surg. 2002 Jun;109(7):2219-26; discussion 2227-30.
    2. Lin DT, Coppit GL, Burkey BB. Use of the anterolateral thigh flap for reconstruction of the head and neck. Curr Opin Otolaryngol Head Neck Surg. 2004 Aug; 12(4): 300-4.