Interpolated Flaps

Excerpt

Local flaps for soft tissue reconstruction are commonly divided into 4 types depending on the type of movement required to transfer the flap into the defect: advancement, rotation, transposition, and interpolation. Advancement, rotation, and transposition involve tissue transfer immediately adjacent to the defect, whereas interpolation transfers tissue over or under intervening normal tissue to reach the defect. For this reason, interpolated flaps are often considered to be "regional" flaps rather than "local" flaps, and more often than not, require a second-stage procedure to divide the bridge of flap tissue, the pedicle, that traverses the normal tissue between the flap donor site and the defect to be reconstructed (see Image. Interpolated Flaps). While the need for a second procedure may be a drawback to many interpolated flap reconstruction techniques, the main advantages of interpolated flaps are their reliable blood supply and their ability to transfer larger amounts of tissue than many other local flap options provide.

The "waltzing" or "walking" flaps were among the first interpolated flaps described. Early reconstructive surgeons, including Sir Harold Delf Gillies, Sir Archibald McIndoe, and Vladimir Filatov, popularized them during WWI and WWII. These flaps require multi-stage operations, as the flaps are initially transferred to an intermediate location before reaching the primary defect because the donor sites are too distant to permit defect coverage with the first stage. After 4 to 6 weeks, the pedicle is released from the donor site, and the intermediate inset site then acts as the base of the flap as the end of the flap that was initially connected to the donor site is then moved either into the defect or a new intermediate inset site closer to the defect. Although the ability to employ a single type of flap in many different areas of the body is appealing, these flaps have fallen out of favor because of the prolonged waiting time between stages and the advent of numerous other techniques that have been developed for use in different anatomical regions and with varying types of tissue.

Examples of currently used interpolated flaps include:

1. Paramedian forehead flap

2. Melolabial flap

3. Postauricular flap

4. Tarsoconjunctival flap

5. Inferior turbinate flap

6. Pericranial flap

7. Facial artery musculomucosal flap

8. Deltopectoral flap

9. Supraclavicular artery island flap

10. Pectoralis major myocutaneous flap

A selection of these is discussed in detail below.