Free-style Flaps

Introduction

Reconstructive surgery has, as its premise, the principle of restoring form and function utilizing surrounding or distant tissues while minimizing morbidity at the donor site. While muscle flaps remain a viable option for reconstructive surgery, their use has become less important in recent years with the advent of perforator flap surgery. No longer is it necessary to take muscle as a carrier of blood supply to the overlying structures; vessels supplying skin flaps can be dissected in a retrograde fashion through their intramuscular course or in the fascia between muscles until the adequate length and caliber required are reached. The extensive development of perforator flap surgery has also allowed for the harvest of tissue in a free-style manner from any part of the body where a perforator or skin vessel is found ( Fig. 62.1 ). This has led to an increase in the number of flaps available, a greater versatility, and even better outcomes in reconstructive surgery. Locating these vessels can be performed safely and reliably with the use of Doppler signal mapping or other imaging study techniques. This tool allows for mapping of all skin vessels over 0.5 mm in size in the area where the flap is to be harvested from. The donor site for tissue transfer is selected, based on the type of tissue desired and required at the recipient site, the volume necessary to fill the defect, the pliability desired, and the color that best matches the recipient site.

Once the vessels are mapped in a given area, even if the surgeon is unfamiliar with the region, flap harvest can begin by surgically exploring the region for vessels of a suitable size. The concept and approach have been termed “free-style flap harvest” and a flap harvested in this manner is termed a “free-style flap.”

In fact, the concept of free-style flap harvest has been introduced in one form or another over many years. Many surgeons have used this approach in cases where anatomic variations were met, or when problems arose during flap harvest such as trauma to the vessels. Taylor and Daniel in 1975 dissected the perforators of the gastrocnemius musculocutaneous flap back to the sural vessels. During Wei and colleagues' anatomic study of the fibula osteoseptocutaneous flap, they performed intramuscular dissection of perforators through the soleus muscle when they were encountered. What they were performing at the time was essentially a free-style flap harvest. Koshima introduced an innovative concept and the surgical technique of “supramicrosurgery.” He harvested flaps from the paraumbilical region and based them on the suprafascial component of skin vessels. The free-style flap harvest principle has some similarity to the previously mentioned approaches, and the vessels supplying the flap are traced in a retrograde fashion through whatever course they take until the appropriate size and length are reached.

Free-style flaps can be harvested as local or free flaps, and can be composed of a variety of tissue types. Reconstructive surgery will continue to rely on flaps that have been studied anatomically and have been proven clinically to be reliable and safe. In addition to being a way of providing tissue as a flap, free-style flap surgery has played a role where anatomic variations are encountered or unexpected situations are met. More recently, it has been used to allow for a flap to be “recycled” and used for the reconstruction of a second defect following a previous reconstruction with a flap. The area is explored for vessels with the use of either Doppler mapping or immediate exploration, the flap is designed based on a set of principles that are discussed later in this chapter, and the flap is harvested. We believe that having had experience with perforator flap surgery has allowed surgeons to feel comfortable in performing free-style flaps, and this in turn has aided in alleviating anxiety when approaching any flap harvest, particularly when it is less familiar to the surgeon. This allows the surgeon to begin flap surgery knowing that many alternative plans are available if an unexpected situation is encountered.

Flap Anatomy

Knowledge of anatomy of the region where a free-style flap is to be harvested is still important. In order to safely carry out the harvest of any block of tissue from any region, it is essential that the surgeon avoid critical structures in order to minimize damage at the donor site. Detailed regional anatomic landmarks, however, play a role that is less significant when dealing with free-style flaps. Ideally, “back-up” flaps can be available in the region where a free-style is to be harvested. This is particularly important when the surgeon begins to explore a new region for free-style flaps. In the authors' experience, the thigh was used initially as the region to explore the reliability and safety of free-style flaps. Given the large experience acquired over the years with flaps from the thigh, it became clear that the thigh is an ideal location to realize this concept. We always marked the anatomic landmarks for the anterolateral thigh flap in the event we encountered problems with the free-style flap. The incisions were planned so that the back-up flap could be used in case the skin vessels to the free-style flap were found to be short or small, or were injured during the dissection. The main landmarks are the location of Dopplered skin vessels. Because our experience and that of others has proven that dissection and anastomosis of vessels ≥0.5 mm is technically feasible and reliable, all 374 vessels that were mapped by Taylor and colleagues can theoretically provide reliable pedicles for a free-style flap.

The area that is selected for a flap donor site is chosen based on the defect to be reconstructed and on a donor site that allows for a well-healed scar in an inconspicuous location. The flap is chosen that allows for versatility in flap design; provision of tissue volume that is adequate to reconstruct the defect; and good match in color, texture, and pliability at the recipient site. Additionally, if sensory reinnervation is desired, the flap is chosen from an area that had sensory nerves that can be harvested with the flap. Whenever possible, the location of the donor site should allow for a two-team approach.

Flap Components

Any type of tissue can be harvested as part of a free-style flap. Typically, free-style flaps are harvested as cutaneous flaps. Other components such as muscle, nerve, or bone can be harvested based on the same vessels if branches also supply those tissues. However, predicting the course of these vessels is difficult. If bone, muscle, or nerve is required to reconstruct a defect, known flaps are recommended for use.

Flap Design