Microsurgery: Transplantation and Replantation by Harry J. Buncke, MD, et al.
  Table of Contents / Chapter 16:
Fibular Free Flaps
  The pedicle to the fibula lies near the juncture of the proximal and middle thirds of the fibula and should be identified and preserved. As the interosseous membrane is divided distal to proximal, the origin of the peroneal vessels becomes apparent. The peroneal vascular bundle should then be isolated and protected. Dissection should proceed proximally to distally, freeing the fibula from remaining fibers of the flexor hallucis longus and tibialis posterior. The Gigli saw is then used to make the proximal fibular osteotomy. As mentioned earlier, the proximal limit of the flap is usually 8 cm distal to the fibular head to avoid injury to the common peroneal nerve. The common peroneal nerve can be palpated just distal to the fibular head if rolled against the fibular neck for identification. The common peroneal nerve is not seen during dissection because it divides into the superficial peroneal nerve, which runs deep to the peroneus brevis muscle, and the deep peroneal nerve, which lies deep to the extensor digitorum longus and tibialis anterior muscles.

After these maneuvers are completed, the flap is tethered only by its vascular pedicle, the peroneal vessels. The tourniquet is then released and the viability of the bone flap observed. The pedicle can then be ligated and divided when the recipient site is ready.

In the osteocutaneous flap, an elliptical incision is made with its central axis along the posterior border of the fibula and beginning 10 cm below the fibular head. The ellipse is designed to incorporate the cutaneous branches of the peroneal artery that are transmitted in the lateral intermuscular septum between the soleus and peroneus longus muscles. Usually, these branches are four in number and are located at the junction of the proximal and middle third of the fibula. Because these cutaneous branches flow through the fascial plexus, they can reliably support an elliptical skin paddle 10 cm x 20 cm. Skin paddles wider than 8 cm, however, require skin grafting of the donor site. The skin paddle should be one-fifth larger than the defect to allow for primary contracture of the skin flap. Linear extension should be made proximally and distally from the ellipse to allow the deeper dissection needed to harvest the fibula.


PLATE XVI- 1 . Anatomy

A. Lateral aspect of the leg shows muscular and vascular anatomy. The midline of the skin island overlaps the axis of the proximal area of the fibular segment to be removed.

B. The entry of the nutrient vessel into the fibular is somewhat variable, but is close to the junction of the proximal and middle thirds of the bone. After entering the bone, it provides ascending and descending intramedullary branches that supply the medulla and inner two-thirds of the cortex. Because the nutrient vessel is small, the peroneal vessels are used for the anastomoses. The outer third of the cortex is richly supplied by periosteal branches, primarily emanating from the muscles and soft tissues around the bone, and these in turn are supplied by the peroneal vessels. Vessels to the skin island lie in or on the septum separating the lateral compartment from the superficial posterior compartment.

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