Flap surgery for wound reconstruction: how it works, types and recovery

A flap is a piece of tissue that is moved from one part of the body to another while keeping, or having reconnected, its own blood supply. BAPRAS, the British Association of Plastic, Reconstructive and Aesthetic Surgeons, explains that because a flap carries its own blood supply it does not rely on the wound bed for blood to heal like a skin graft does. It also notes that flaps give a good colour match and fill a wound well.

The aim of reconstruction after removing a skin cancer, as BAPRAS describes it, is first to remove the tumour with an appropriate margin of safety and secondly to fill the hole with a good aesthetic reconstruction. How complex that is depends on the size and site of the defect and other medical conditions the patient may have.

BAPRAS sets out a sequence of options. The simplest is healing by secondary intention, used if the wound is small or superficial, which needs extended time for dressings; some sites, such as the forehead and inner aspect of the eye, heal well this way. Next is direct closure, suturing the wound where there is enough skin, which heals quickly and keeps the scar as short as possible.

Skin grafts are used if the wound cannot be sutured and involve harvesting skin from one part of the body to rebuild a wound elsewhere. They need to pick up a new blood supply at the site, so they only work if there is a good blood supply at the base of the wound, and some sites such as bare bone are not suitable. Flaps are the next step when a graft will not do.

Local flaps use skin from next to the wound and move it into place. BAPRAS names several by shape or blood supply. The transposition flap is often used on the head and neck and approximates a rhomboid shape, with scars arranged to blend into normal creases of the face. The keystone flap is useful for closing wounds on the arms and legs. The V-Y advancement flap is developed as a V shape and, once advanced, takes the shape of a Y; it is particularly useful for defects along the side of the nose. BAPRAS adds that many of these flaps can be performed under local anaesthetic.

Regional flaps come from further away and can bring other tissues such as muscle if needed. A free flap is a more complex operation in which a large area of tissue with its own blood vessels is raised, completely freed and moved to the wound, where the isolated blood vessels are reconnected to nearby blood vessels to carry blood into and out of the flap.

The Northern Care Alliance explains that a free flap is a block of spare tissue from a part of the body at a distance from the injury, which can include muscle, fat and skin with blood vessels. Common donor places are the thighs, calves or back. A free flap may be offered when an injury has caused a skin and soft tissue defect on a limb that cannot be directly closed or covered by another method, sometimes with a fracture of the bone underneath. If the defect and underlying structures are left uncovered there is a high risk of infection that could become limb or life threatening.

The leaflet says the operation is done under general anaesthetic, can last between 6 and 8 hours or longer, and may involve several surgeons working at the same time. Microsurgery uses a microscope and special instruments to attach the blood vessels from the flap to the injured limb to keep the flap alive. Skin grafts or local flaps may be needed to cover remaining defects.

The leaflet lists general surgical risks including bleeding, wound infection, adverse scarring, altered sensation and pain, plus risks of a long general anaesthetic such as blood clots. Specific risks include damage to surrounding nerves and blood vessels. If the blood supply to the flap blocks off after the operation the patient may need to return to theatre, and there is always a risk that the flap may not survive.

After a free flap for a limb injury, the leaflet says the first night is spent in intensive care so the flap can be checked regularly, with special tests to ensure it is doing well. For the following days patients are closely monitored, and have to stay in bed with the limb raised on supports until the team are happy for them to start mobilising. Before discharge a therapy team checks the patient is safe to go home, and a follow-up is arranged within 2 to 3 weeks.

For skin grafts used alongside flaps, BAPRAS says the donor site of a split thickness graft is usually healed by two to three weeks, and that the graft is checked after five to seven days.

BAPRAS says your surgeon will guide you about the choices to rebuild a wound, and will explain the risks and complications of surgery, what to expect and the recovery time. Useful questions include why a flap is recommended rather than a graft, where the tissue will come from and what the donor site will look like, how long the operation and hospital stay are likely to be, and who to contact if you are worried after discharge.

On the NHS, reconstruction after cancer removal or injury is planned by plastic surgery teams, often in regional specialist centres, and complex microsurgery is concentrated in a smaller number of units.

Private plastic surgeons also perform flap reconstruction, mainly after cancer surgery. The operations are the same, so the practical differences are the choice of surgeon and the setting. Ask who would manage complications and whether intensive monitoring facilities are on site.