The gracilis flap is a specialized technique in reconstructive surgery where tissue is moved from the inner thigh to another location on the body to repair a defect or restore function. This procedure falls under the category of a “flap,” which is a block of tissue, often including skin, fat, and muscle, that is transferred with its own dedicated blood supply intact. Unlike a skin graft, which relies entirely on the recipient site for nutrients, the flap’s built-in circulation ensures its survival and integration into the new area. When the tissue is completely detached from the donor site and reconnected to new blood vessels at the recipient site using microsurgical techniques, it is termed a free flap. The gracilis muscle is a popular choice for this kind of free tissue transfer due to its reliability and low impact on the donor limb.
Why the Gracilis Muscle is Ideal for Flap Surgery
The gracilis muscle is situated in the inner thigh, where it is the most superficial of the adductor muscles. Its anatomical features make it an attractive donor site for reconstructive surgery because it is considered an expendable muscle. Other muscles in the thigh, such as the adductor longus and magnus, compensate for the lost function, meaning its removal results in minimal functional deficit.
The muscle is long and relatively thin, allowing it to be used for a variety of defect shapes and sizes. It has a highly consistent and dependable blood supply, known as a vascular pedicle, which originates from the medial femoral circumflex artery. This pedicle is long enough for the complex microvascular connections required in free flap surgery. The reliable anatomy and small size contribute to a relatively straightforward harvest technique compared to other muscle flaps.
Major Reconstructive Uses
The versatility of the gracilis muscle is utilized across multiple reconstructive specialties, including facial reanimation, breast reconstruction, and soft tissue coverage.
Dynamic Facial Reanimation
One specialized application is dynamic facial reanimation, often referred to as “smile surgery,” for patients suffering from facial paralysis. In this procedure, the muscle is transferred to the face, and its nerve (the obturator nerve) is connected to a functioning nerve in the face, such as the masseteric nerve, to restore voluntary muscle movement and a symmetrical smile.
Breast Reconstruction
The gracilis flap is also utilized extensively in breast reconstruction, particularly in the form of the Transverse Upper Gracilis (TUG) flap. This technique uses the muscle, along with overlying skin and fat from the upper inner thigh, to create a new breast mound after a mastectomy. The TUG flap is an alternative option for patients who may not be candidates for abdominal-based reconstruction due to prior surgery or lack of sufficient abdominal tissue.
Soft Tissue Coverage
Beyond functional and aesthetic reconstruction, the gracilis flap is frequently used to cover soft tissue defects in the perineum, groin, and lower extremities. The bulk and robust blood supply of the muscle provide a durable covering for complex wounds caused by trauma, cancer removal, or chronic infection. When harvested with a patch of skin, known as a myocutaneous flap, it can simultaneously fill a deep cavity and provide skin coverage.
The Procedure and Post-Operative Recovery
The gracilis flap procedure involves two surgical teams working simultaneously: one team harvests the muscle from the inner thigh, and the other prepares the recipient site. The muscle is carefully dissected, ensuring the main vascular pedicle and, if needed for functional repair, the obturator nerve are kept intact. The flap is then completely detached and transferred to the recipient site where the microsurgical team reconnects the artery and veins to local blood vessels under a high-powered microscope.
A primary concern for patients is the recovery of the donor site. While studies report that the functional loss is minimal due to the compensatory muscles, a temporary decrease in hip adduction strength has been measured, though patients typically do not notice this in daily activity. Some patients may experience a small area of numbness or hypesthesia on the inner thigh corresponding to the sensory distribution of the obturator nerve.
Patients are generally hospitalized for four to five days following the surgery, with the initial focus on monitoring the flap’s blood flow and managing pain. Activity restrictions are often put in place for about six weeks to protect the inner thigh incision and ensure proper healing. This includes avoiding heavy lifting, strenuous exercise, and extreme movements. Specific restrictions include:
- Avoiding heavy lifting.
- Avoiding strenuous exercise.
- Avoiding extreme movements like bending the hip more than 90 degrees.
- Avoiding abducting the leg widely.
Donor site complications like wound dehiscence, infection, or seroma are possible. The risk is higher when a large skin paddle is taken with the muscle, requiring a longer period of drain placement.