Dolph Houben

37 Vascularized Bone Grafts, a closer look at the free fibula flap 2 proximally is important to prevent inadvertent dissection anterior to the FHL and potential injury to the vessel more distally. (Fig 1.4). If a composite osteomuscular flap (including soleus) is planned, the peroneal muscular branches to the soleus should be preserved, otherwise, these can be ligated and divided. The initial posterior dissection is completed by carefully elevating the peroneal vessels from the fibula to prevent injury when the proximal osteotomy is performed. Next, the anterior dissection is performed. The dissection begins proximally and subperiosteally to first identify the peroneal nerve. Dissection directly on the bone surface is critical to protect the peroneal nerve at the level of the fibular neck. As the lateral compartment muscles are elevated from bone, the common peroneal nerve is visualized on the deep surface of the elevated muscles (Fig. 1.5). Its division into superficial (lateral compartment location) and deep (anterior compartment location) branches are next demonstrated. Once the nerve is visualized, the remainder of the dissection is extraperiosteal to preserve the periosteal blood supply of the bone. Progressing distally, the lateral compartment muscles are elevated sharply, leaving wisps of muscle on the bone surface. Preserving a ‘cuff’ of muscle, as sometimes described, is erroneous, risking injury to both peroneal nerve branches and the tibialis anterior vessels. Besides, this potentially necrotic muscle cuff may also block angiogenesis to the periosteal surfaces from adjacent soft tissue. Next, the anterior compartment musculature is elevated from the bone. Proximally, the deep peroneal nerve is identified. Once visualized, it is easily protected and proximal-to-distal extra- periosteal elevation of the anterior compartment is performed. The anterior dissection at this point stops with the visualization of the interosseous membrane and tibialis anterior vessels. Next, the fibula may be divided. We prefer to take more fibula than recipient-site measurements suggest to be necessary. Loss of the fibular diaphysis is well tolerated in the donor leg. Importantly, the optimal positioning of the fibula in the recipient site often requires adjustment, to maximize pedicle length and position for local vascular anatomy, and given the variability in nutrient artery location in the fibula. Harvest of a short fibular segment initially risks the potential loss of its endosteal blood supply.