Dolph Houben

39 Vascularized Bone Grafts, a closer look at the free fibula flap 2 Figure 2: If desired a skin paddle can be designed based on perforator vessels of the peroneal vessels, by using a Doppler ultrasound. Here we demonstrate an example of dissection of an osteocutaneous free fibular flap. While carefully protecting the previously mobilized neurovascular structures with gentle retraction, the proximal osteotomy is to be made with a Gigli saw (Fig. 1.6). Next, the distal cut made, maintaining 7-8 cm of the distal fibula at the ankle, to prevent valgus ankle instability (Fig 3.1). In children, a distal tibiofibular syndesmotic fusion must be performed to safely avoid valgus deformity regardless of the length of the remaining fibula. Once both osteotomies are made, the fibular flap mobility facilitates the remainder of the dissection. Next, the fibular harvest is completed by distal-to-proximal dissection. The interosseous membrane is sharply divided, and the fibula gently pulled laterally (Fig. 3.2). The tibialis posterior muscle lies directly behind the interosseous membrane, covering the peroneal vessels from an anterior view. At the distal end of the fibula, dissection between the tibialis posterior and flexor hallucis longus permits visualization of the peroneal vessels distal to the fibular bone flap (Fig. 3.3). The vessels are doubly-ligated at this level. Leaving one suture long facilitates subsequent exposure of the vessels, now covered by the tibialis posterior muscle by the use of gentle longitudinal tension. Tension stabilizes the vessels as the tibialis posterior muscle is divided. The plane of dissection is directly anterior to the peroneal bundle. Meticulous vessel exposure begins distally, dividing the tibialis posterior muscle into short segments and a layered fashion. This permits identifying and ligating multiple peroneal muscular perforators as they are encountered (Fig. 3.4). If an osteocutaneous fibular flap is to be used, division of the tibialis posterior must pause and the cutaneous perforators dissected. They may lie either within the muscle or in the lateral intermuscular septum. The posterior border of the skin flap is made at this point, and the perforators followed to the peroneal vessels. Dissection is continued proximally until the tibialis posterior is completely released from the fibula, leaving only the vascular pedicle and flexor hallucis longus muscle attached.