The TFL muscle takes origin from the anterior iliac crest in an arc and inserts into the iliotibial tract. The vascular pedicle enters the TFL muscle at the level of the junction of the proximal and middle thirds of an axis drawn from the anterior superior iliac spine to the lateral patella.
The TFL muscle flap is supplied by the ascending branch of the lateral circumflex femoral artery. The descending branch supplies the anterolateral thigh and rectus femoris flaps. The descending branch can be harvested with the anterolateral thigh skin to enlarge the perfused vascular territory of the TFL flap. Taking a large width of flap can create a significant aesthetic donor deformity, especially if skin grafting is required to close the defect.
The lateral femoral cutaneous nerve of the thigh travels through the flap skin and fat proximally to supply distal flap sensation.
The vascular inflow to the TFL muscle (rectus femoris and sartorius cut away segmentally for visualization)
The fascia lata (the deep fascia of the thigh) hugs the entire thigh like a set of tights. Laterally, the fascia lata thickens to form the iliotibial tract which attaches distally to the lateral condyle of the tibia. The TFL muscle is enclosed by the fascia lata and distally the muscle fibers coalesce with the iliotibial tract. The thickness of the fascia lata over the TFL muscle makes it a strong fascial donor site suitable for reconstructing abdominal wall defects, and avoiding prosthetic mesh.
The patient is prepped and draped supine with a bump under the ipsilateral hip. The anterior part of the flap runs along the axis of the septum between the vastus lateralis and the rectus femoris. A line drawn from from the anterior superior iliac spine to the lateral patella locates this anterior landmark. The entry point of the pedicle is at the level of the junction of the proximal and middle third of the aforementioned line. The posterior aspect of the TFL is denoted by the axis of the femur. The flap is marked as an ellipse over the axis of the TFL muscle and to incorporate the pedicle proximally.
The flap is outlined using an anterior edge axis of the antero-superior iliac spine to lateral patella (yellow line) and the axis of the femur (green line). The anterior axis of the flap is the former, and the posterior axis is the latter. The level of entry of the perforator into the TFL is approximately the level of the junction of the proximal and middle third of the ASIS-lateral patella axis.
The flap is elevated from distal to proximal. The skin and deep fascia are incised together and the plane deep to the iliotibial tract fascia is elevated sharply while coagulating small perforators. As one ascends proximally, the space between the rectus femoris and vastus lateralis is retracted with a self retaining retractor to identify the descending branch of the lateral femoral circumflex artery. The ascending branch is then identified as one proceeds in a superior direction.
With the ascending branch identified, its course to the TFL can be isolated. The proximal flap is then divided by electrocautery while protecting the pedicle. The pedicle can be traced to the origin of the lateral femoral circumflex vessels to gain length and caliber.
The perforator to the muscle is large and easily identified. It is surrounded on all sides and the pedicle is traced to the lateral circumflex femoral vessels.
Tensor fascia lata muscle flap: The flap can be harvested without a skin paddle, using only the muscle and fascia.
Chimeric flaps: the TFL flap can be harvested on a common pedicle with the anterolateral thigh and/or the rectus femoris flap.
Osteomusculocutaneous flap: A portion of external table of iliac crest can be harvested with the proximal flap for vascularized bone grafting.