Reconstruction of Through-and-Through Mandibular Defects with the Fibula Osteocutaneous and Lower Lateral Leg Perforator Free Flaps

Through-and-through defects of the mandible that include mucosa, bone, and skin are typically reconstructed with free osteocutaneous flaps by one of three techniques: (1) folding of the skin paddle around the bone flap to resurface both the intraoral and skin defects with an intervening deepithelialized segment, (2) an independent skin paddle in a chimeric fashion to resurface the skin defect, or (3) a second free flap to resurface the skin defect. The simplest solution is folding of a single skin paddle to reconstruct both intraoral and extraoral defects; however, this may not be possible, as the soft-tissue requirements may exceed the availability in the lower leg or result in marginal flap necrosis. In contrast, use of two independent skin islands whether as a chimera or second free flap is a superior option, as it allows for greater degrees of freedom and easier insetting.

The fibula osteocutaneous free flap is the gold standard for mandible reconstruction. The bone receives both endosteal and periosteal blood supply from the peroneal artery, whereas the overlying soft tissue is supplied by septocutaneous perforator(s) usually emerging at the junction of the middle and distal thirds of the fibula. In contrast, the skin of the proximal one-third of the lateral leg is supplied by a perforator that travels through the soleus muscle, and can be located approximately 7 to 15 cm distal to the fibular head.^1–3 The source vessel is either the peroneal artery, the posterior tibial artery, or the tibioperoneal trunk.² This lower lateral leg flap was described by Yajima et al. in 1994.⁴ The pedicle length is usually 4.5 to 10 cm, with an arterial diameter of 0.8 to 2.5 mm and a venous diameter of 1.2 to 2.8 mm.^1,5 It can resurface a moderate to large cutaneous defect in either a chimeric fashion (peroneal vessel origin) or as a free flap. When used as a chimeric flap, its inset is limited by tethering from the origin of the peroneal pedicle. When used as a free flap, there are unlimited positional degrees of freedom, albeit with the necessity of a second set of microvascular anastomoses. The donor site can be closed primarily for flap widths less than 6 cm. The primary advantage of the lower lateral leg flap is that through-and-through defects can be reconstructed with a single leg donor site.

An illustrative case is provided. The patient had an advanced squamous cell carcinoma, requiring right hemimandibulectomy with aggressive intraoral and external skin resection. (See Figure, Supplemental Digital Content 1, which shows through-and through mandible defect comprising the right hemimandible from right parasymphysis to the condyle, http://links.lww.com/PRS/E794. See Figure, Supplemental Digital Content 2, which shows indocyanine green angiography demonstrating normal perfusion of the fibula and lower lateral leg flap, http://links.lww.com/PRS/E795. See Figure, Supplemental Digital Content 3, which shows lingual nerve repaired with an interposition nerve allograft, http://links.lww.com/PRS/E796. See Figure, Supplemental Digital Content 4, which shows fibula flap inset in place with custom three-dimensionally–printed 2-mm reconstruction plates, http://links.lww.com/PRS/E797. See Figure, Supplemental Digital Content 5, which shows fibula flap skin paddle used for intraoral resurfacing, http://links.lww.com/PRS/E798.) Figure 1 demonstrates a lower lateral leg flap, originating from the tibioperoneal trunk, dissected through the soleus muscle. Figure 2 shows the final inset, with the lower lateral leg flap anastomosed to a separate set of neck vessels. When compared to two free flaps from separate donor sites, such as the fibula paired with anterolateral thigh or radial forearm flap, the lower lateral leg flap allows for reconstruction of large through-and-through mandible defects using a single donor site. In some instances, only a single vascular anastomosis is needed when the vascular pedicles share a common origin.

Fig. 1.

The lower lateral leg perforator flap and the fibula osteocutaneous flap.

Fig. 2.

The fibula osteocutaneous flap is used for bone and intraoral reconstruction, anastomosed to the left neck vessels. The lower lateral leg perforator flap is anastomosed to the right neck vessels.