Reconstructive

Complex Wound and Defect Reconstruction

Free flap reconstruction is an advanced surgical technique used to rebuild areas of the body where there has been major tissue loss due to trauma, cancer removal, infection, or radiation damage. In this procedure, tissue such as skin, fat, fascia, muscle, or bone is taken from one area of the body and transferred to another. Unlike a skin graft, the tissue is fully detached and then reconnected at the new site using microsurgery, which involves joining tiny arteries and veins under a microscope. Once these blood vessels are reconnected and blood flow is restored, the flap becomes living, healthy tissue in its new location.

Free flap surgery allows surgeons to recreate complex structures, restore function, and achieve durable long-term healing in areas that would not recover with simpler methods.

Indications

Not all wounds can be repaired using stitches, skin grafts, or local tissue. Some injuries or surgical defects are too deep or too extensive, and the structures that have been lost require more than just skin. A wound cannot be closed with a skin graft when there bone, tendons, metal plates, nerves, or major blood vessels exposed. Skin grafts require a healthy, well-vascularised wound bed to survive, Free flaps bring their own blood supply to the area, improving healing in tissues that have been damaged by trauma, infection, or radiation.

Another important advantage of free flaps is their ability to provide composite reconstruction, meaning they can supply multiple tissue types at the same time. For example, some head and neck defects require bone for structure, muscle for bulk, and skin for both lining and external cover. In the limbs, a patient with an open fracture may need bone to bridge a gap, muscle to fill a cavity or control infection, and skin for surface coverage. Free flaps can include combinations of bone, skin, muscle, and fascia all connected by a single blood vessel, making them uniquely effective for restoring areas where several layers of tissue are missing.

Examples of conditions requiring free flap reconstruction

Free flaps are commonly used in traumatic injuries such as compound or open fractures, especially those involving the lower leg or forearm. In these injuries, bone or metal hardware may be exposed, and there may be significant loss of muscle or skin. These wounds are at high risk of infection, poor healing, and long-term disability unless they are covered with healthy, vascularised tissue.

Free flaps are also essential after severe facial trauma, such as injuries resulting from motor vehicle accidents, machinery accidents, dog bites, or explosions, where large areas of skin, soft tissue, and even bone may be missing. In these cases, free flap reconstruction helps restore appearance, symmetry, and the ability to chew, speak, or close the eyes.

In the setting of cancer treatment, free flaps are frequently required after the removal of large tumours from the head and neck region. For example, patients may need reconstruction of the jaw, cheek, lip, and tongue. Free flaps also play an important role in reconstructing defects after sarcoma removal in the limbs or trunk, where wide margins of tissue must be removed to ensure cancer clearance.

Types of Free Flaps

Free flaps are chosen based on the type of tissue that needs to be replaced.

Bone flaps are used when there is structural loss that needs to be restored, such as the jaw, upper limb, or lower limb.

Common bone flaps include:

Free fibula flap:
One of the most commonly used bone flaps that provides a long segment of bone that can be shaped to match the jaw or to bridge bone gaps in the limbs. It can also include skin if both internal lining and external coverage are needed.
Scapula flap:
Bone flap taken from the shoulder blade which offers good-quality bone with flexible soft tissue options, making it well suited for complex facial defects.
Medial femoral condyle flap:
A smaller bone flap taken from the inside of the knee that is extremely useful for reconstructing small defects or treating non-healing fractures in the upper limb.

Fasciocutaneous flaps consist of skin and the underlying fascia and are ideal for resurfacing wounds while maintaining a natural contour.

The common fasciocutaneous flaps used include:

Anterolateral thigh (ALT) flap:
Highly versatile and provides a large piece of skin and fascia, making it suitable for reconstructing lower limb wounds, oral cavity defects, and large head and neck defects.
Thoracodorsal artery perforator (TDAP) flap:
Thin, flexible flap taken from the side of the chest and is useful in the upper limb and in neck reconstruction.
Radial artery forearm flap (RAFF):
One of the thinnest and most pliable flaps, making it ideal for delicate reconstructions inside the mouth, throat, or facial structures where thin, mobile tissue is essential.

Muscle flaps bring a rich blood supply and are excellent for wounds that are infected, deep, or involve radiation-damaged tissue.

The common muscle flaps include:

Gracilis muscle flap:
Taken from the inner thigh, is small, reliable, and often used for lower limb wounds or for facial reanimation surgery.
Latissimus dorsi flap:
Taken from the back, is one of the largest and most reliable muscle flaps available. It provides substantial bulk and can be used for major reconstructive needs, whether in the head and neck, upper limb, or lower limb.

In some cases, a muscle flap is combined with skin (a myocutaneous flap) to provide both volume and external coverage.

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Free Flap Healing and Monitoring

Once the flap is transferred to its new location, the artery and vein of the flap is connected to blood vessels in the recipient site. Blood flow through the flap begins immediately once the connections are open, and this restored circulation allows the flap to survive.

Monitoring the flap closely after surgery is essential, particularly in the first 72 hours. During this time, nurses and doctors check the flap frequently to ensure the blood supply to the flap is maintained. They assess the colour, temperature, softness, and capillary refill of the flap, and may perform a small needle test to check for bleeding. A Doppler monitor is often used to listen to the blood flow through the flap’s artery or vein. For flaps placed inside the mouth or in areas not easily visible, an implantable Doppler or small monitoring device may be used.

If there are any signs of reduced blood flow, such as the flap becoming too pale, too dark, swollen, or cool, an early return to the operating theatre is required. As the flap stabilises, the frequency of checks decreases, and patients gradually return to normal activity.

Over time, tiny new blood vessels grow into the flap, making it even more secure. Swelling is normal in the early days but gradually settles. On the limbs, compression is often required before mobilising on or using the limb. Full healing and reshaping can take several months. Oftentimes, smaller revisional procedures are recommended months down the line to revise large or bulky flaps to improve their appearance. The goal of free flap reconstruction is to restore both appearance and function in the most reliable and long-lasting way possible.