Derrick T. Lin
INTRODUCTION
Reconstruction of the total maxillectomy defect is among the most challenging faced by the head and neck reconstructive surgeon. Defects in this area are most often due to resection for malignant tumors but also may occur with trauma, osteoradionecrosis, or infection/inflammation.
Anatomically, the two paired maxillae form the structural support of the midface. These paired structures provide separation of the oral, antral, and orbital cavities, forming the foundation necessary for facial contour and expression, mastication, speech, and deglutition.
The goals of palatomaxillary reconstruction are therefore to restore separation of the oral and antral cavities, correct hypernasal speech, and prevent regurgitation of foods and liquids into the nasal cavity. The simplest rehabilitation option is the use of an obturator. The advantages are short operative time, short post-operative stay, and complete visualization of the maxillectomy defect for oncologic surveillance. However, in larger defects where the anterior projecting element of the maxilla has been removed, reconstruction with bone is preferred.
The fibular osteocutaneous free flap was described by Taylor et al. in 1975. It is based on the peroneal artery and its two venae comitantes and was initially used for the reconstruction of an open fracture of the lower extremity. Hildalgo in 1989 was the first to adapt its uses for the head and neck in the reconstruction of a segmental mandibulectomy defect.
The fibula provides a large segment of bone for reconstruction where approximately 22 to 25 cm of bone can be harvested. The fibular flap can be transferred as either a free osseous or a free osteocutaneous flap. In the setting of the palatomaxillary defect, the cutaneous portion is necessary for reconstruction of the palatal surface. The width of the skin paddle is often defined by the ability to achieve primary closure of the donor site. If the donor site cannot be closed without excessive tension, a skin graft may be required.
Although the pedicle length may reach up to 12 cm, it is often limited by the bifurcation with the posterior tibial artery. The vascular supply to the skin paddle arises from either a septocutaneous perforator arising between the peroneus longus and the soleus muscles or a musculocutaneous perforator through the flexor hallucis longus and soleus muscle.
HISTORY
When considering the fibula as a donor site for reconstruction of the total maxillectomy defect, the history should include the patient’s expectations. While some patients will be pleased with a soft tissue reconstruction, others will demand dental restoration. The fibula provides the opportunity to restore the dentition by providing a bony infrastructure for osseointegrated implants. This is not possible with other forms of soft tissue reconstruction.
PHYSICAL EXAMINATION
The physical examination should include a careful evaluation of the defect and the donor site. The fibula is ideal for infrastructure defects that do not require reconstruction of the orbital rim. High vertical defects require more bone that the fibula can provide. The donor site should be evaluated to assure that there is no evidence of trauma or prior surgery that may preclude using this donor site. The donor site must also be carefully inspected for venous stasis ulcers, lesions, or varicose veins. The overall thickness of the skin, subdermal component, and muscle must be carefully evaluated to ensure a good match for the defect.
INDICATIONS
The palatomaxillary defect involving the anterior projecting element is ideal for the use of an osteocutaneous flap. Radial forearm osteocutaneous, scapular, iliac crest, and fibular free flaps have been reported for reconstruction of this defect.
The fibular free flap should be considered in the setting of an intact orbital floor and rim and a total maxillectomy defect extending beyond the anterior projecting element. The bone provides the anterior projection, contouring, and support; the cutaneous component is used to recreate the palatal mucosal defect; and the muscle of the flap is used to fill in the midface volume defect. Additionally, the bone of the fibula can allow for future osteointegrated implants.
The fibular free flap, however, would not be the preferred reconstruction if a significant portion of the orbital floor and rim has been resected. Although many options have been reported in this setting, the scapular free flap using the tip for the orbital floor and rim would be my choice of reconstruction.
CONTRAINDICATIONS
There are some rare anatomic anomalies that would preclude the use of the fibular free flap. Three vessel runoff to the foot is a prerequisite for the use of the fibular flap, unless the peroneal artery is the nonrunoff vessel. Preoperative MRA is used to determine the patency of the arterial vasculature.
Mönckeberg calcinosis is a relative contraindication for fibular free flap reconstruction. This entity is characterized by calcium deposits in the medial layer of the artery and therefore cannot be diagnosed by MRA but only by plain radiography of the lower extremities. The arteries are firm and nonpliable making it difficult to accomplish a secure anastomosis in these patients.
The patients’ donor site must be carefully inspected. Evaluation of the thickness of the lower extremity is critical in the reconstruction of the palatomaxillary defect. In patients with circumferentially large lower extremities, consideration of other donor sites may be necessary. The presence of venous stasis, varicose veins, and previous surgery or trauma to the lower extremity may be a relative contraindication for the use of the fibular flap.
PREOPERATIVE PLANNING
An MRA is performed for all patients being considered for a fibular free flap. Three-vessel runoff or anterior and posterior tibial artery runoff to the foot is required for successful harvest. I also recommend a preoperative radiograph of the lower extremity to exclude Mönckeberg calcinosis.
SURGICAL TECHNIQUE
The leg is positioned with a bump under the foot and the knee flexed at approximately 45 degrees. A tourniquet is placed on the upper thigh and the leg rotated slightly medially. The leg is then prepped and draped from the thigh to the foot.
The topographical anatomy is outlined on the lateral aspect of the leg. The bony landmarks of the posterior aspect of the fibular head superiorly and the lateral epicondyle of the ankle inferiorly are identified. A line is drawn from the posterior aspects of these bony landmarks. The intermuscular septum corresponds to this line with a slight 10-degree angle posteroinferiorly. The peroneal nerve runs approximately 1 to 2 cm below the fibular head.
A Doppler is used along the intermuscular septum to identify the skin perforator. Using a “pinch test,” the skin is grasped using the skin perforator as the epicenter of the flap. The width of the proposed cutaneous portion is based on this maneuver to ensure primary closure of the donor site. A 6-cm strut of bone is left both superiorly and inferiorly to ensure stability of the ankle.
The tourniquet is then elevated up to 350 degrees of mercury. The anterior skin incision is made through the level of the muscular fascia. A subfascial plane overlying the peroneus longus and brevis muscles is dissected posteriorly allowing identification of the cutaneous perforators. These perforators are marked for future reference.
The peroneus longus and brevis muscles are then retracted anteriorly allowing access to the intermuscular septum medial to the fibular bone. The intermuscular septum is divided allowing access to the anterior compartment consisting of the extensor hallucis and extensor digitorum longus. This muscular complex is then elevated off the fibula exposing the interosseous septum. Sharp incision of the interosseus septum completes the anterior dissection revealing the posterior tibialis muscle.
The posterior skin incision is made to the level of soleus muscle. Similarly, dissection is performed into the subfascial plane. A cuff of soleus muscle is routinely taken at this point to protect the cutaneous perforators. Deep to the soleus lies the flexor hallucis longus muscle. The fascia of the flexor hallucis longus muscle is incised, allowing release of the posterior tibial vessels medially away from the flap harvest.
Using a right-angle clamp, the distal aspect of the fibular bone is isolated allowing 6 cm of bone to be left in both the distal and the proximal aspects of the fibular bone. The osteotomies are then made using the sagittal saw. A window of fibular bone is taken superiorly to allow for later pedicle dissection. The fibular bone is then distracted. The flexor tendon is identified and divided taking the entire flexor hallucis longus with the fibular free flap. The distal vascular pedicle is identified, clamped, divided, and ligated. The dissection continues with division of the posterior tibial muscle at the level of the chevron. This is done from a distal to proximal fashion until the pedicle is identified and dissected to its junction with the posterior tibial artery.
The peroneal artery is then identified and isolated in 360-degree fashion with its two venae comitantes. The tourniquet is released allowing reperfusion of the flap. The skin is examined carefully to ensure flap viability. A minimum of 15 minutes of reperfusion is necessary prior to harvest.
Once the defect is created (Fig. 26.1), the flap is then harvested from the leg. The flap is brought to the back table, and under microscopic guidance, the artery and veins are dissected from each other (Fig. 26.2).
FIGURE 26.1 The total and near-total defect of the maxilla is typically approached through a Weber-Ferguson incision (inset). The maxillectomy defect can easily be accessed through this approach.
FIGURE 26.2 The fibular free flap provides a cylindrical bone graft The peroneal artery and vein run parallel to the bone graft. The vessels can be dissected from the graft to gain length on the vascular pedicle.
The defect is then carefully analyzed. The contouring of the maxilla is created using a template fashioned to the resection specimen. The length of the fibular bone and appropriate closed osteotomies are determined based on this template.
To achieve appropriate length, the proximal periosteum is dissected to allow for the longest pedicle length possible. Using a sagittal saw, the bone is then contoured to the appropriate length (Fig. 26.3). The previously determined closed osteotomies are then performed to create the contour of the maxilla. Using 2.0 miniplates, the bone is then fashioned in place. Anteriorly, the bone is secured to the remnant maxilla. Laterally, the bone is secured to the remnant zygoma (Fig. 26.4).
FIGURE 26.3 Multiple osteotomies can be made in the bone to provide the contour required for reconstruction of the maxilla.
FIGURE 26.4 The bone graft is fixated to the native bone using miniplates. The soft tissue and skin paddle are used to line the palatal mucosal defect.
The combination the flexor hallucis longus, soleus muscle are then brought into the midface to recreate fullness. The skin overlying the flap is then sewn into the mucosal defect. Prior to insetting the flap, a submucosal tunnel is made within the buccal fat into the subperiosteal plane lateral to the mandible and into the neck. The facial artery and vein are taken at the level of the mandible for microvascular anastomosis. The arterial anastomosis is done under microscopic guidance using a 9-0 nylon suture, and the venous anastomosis is usually completed using either a coupler or 8-0 nylon sutures.
Closed suction drains are placed both in the neck and in the donor site. A cast is placed on the lower extremity. A nasogastric tube is placed on the contralateral side. A temporary tracheostomy should be performed if there is significant edema.
POSTOPERATIVE MANAGEMENT
The cast is kept on the lower extremity for 5 days. Once the cast is removed, physical therapy is started with partial weight bearing.
Doppler monitoring of the flap is essential. The septocutaneous/musculocutaneous perforator to the skin should be identifiable with the Doppler. Pinprick testing can also be used as an adjunct to Doppler monitoring. Immediate exploration is indicated if there are signs of arterial/venous insufficiency.
A hematoma must also be carefully watched for either in the head and neck or the donor site. In the head and neck, a small blood collection could lead to venous congestion of the flap.
Hematoma in the donor site may lead to compartment syndrome or breakdown of the wound and should also be addressed immediately.
Nutrition is typically given through a nasogastric tube for a minimum of 7 days depending on the amount of tongue resected and whether the patient has received radiation therapy. I usually wait 2 weeks prior to initiating an oral diet in the postradiated patient. I recommend speech and swallow evaluations in all of these patients.
COMPLICATIONS
Hematomas were previously reported in up to 25% of patients with long bone reconstruction attributed to oozing from the exposed medullary surfaces of the fibular bone. My rate for hematoma in the head and neck is about 10%. As previously mentioned, immediate exploration is required once a hematoma is diagnosed.
Flap failure occurs at a rate of 2% at our institution, the majority of which are related to venous congestion. Emergent exploration is essential when there is presumed arterial or venous insufficiency. Leeches may be used when there is continual venous congestion where exploration reveals patency of the venous anastomosis or successful revision is performed. Donor site complications include a risk of footdrop secondary to injury to the common peroneal nerve. This complication may be avoided by meticulous dissection of the nerve early in the dissection. A 6-cm segment of bone should be left distally above the lateral malleolus to ensure ankle stability. Compartment syndrome may also rarely occur due to tight closure donor site. Judicious use of a skin graft should be considered in the setting of difficult donor site closure.
RESULTS
Reconstruction of the midface is one of the biggest challenges in head and neck reconstruction. Evaluation of the defect and possible reconstructive sites are essential for success. The fibular free flap is an excellent option in defects involving the anterior projection with an intact orbital floor and rim. Flap failure is rare in my experience. Patients undergoing successful repair should expect good cosmesis, speech, and swallowing function.
PEARLS
• Preoperative MRA and plain radiographs of the lower extremity are necessary.
• Patients with thin lower extremities are ideal for palatomaxillary reconstruction.
• Harvest with flexor hallucis longus allows for obliteration of the maxillary defect.
• Use of a premade template of the defect or the resection specimen is useful for accurate reconstruction.
PITFALLS
• Footdrop may occur if the peroneal nerve is not carefully preserved.
• Avoid using this flap in patients in whom the peroneal artery is the major blood supply to the foot.
• Avoid using this flap in patients with venous stasis ulcers, varicose veins, edema of the lower extremity, or a history of previous surgery or trauma to the drain site.
• Not an ideal flap for reconstruction in patients with defects of the orbital floor or orbital rim
• Ankle stability may be threatened unless 6 cm of distal bone above the lateral malleolus is preserved.
INSTRUMENTS TO HAVE AVAILABLE
• Standard head and neck surgical set
• A reciprocating saw
• Plating set
SUGGESTED READING
Hildalgo D. Fibula free flap: a new method of mandible reconstruction. Plast Reconstr Surg 1989;84:71.
Beppu M, Hanel D, Johnston G, et al. The osteocutaneous fibula flap: an anatomic study. J Reconstr Microsurg 1992;8: 215–233.
Futran ND, Wadsworth JT, Villaret D, et al. Midface reconstruction with the fibula free flap. Arch Otolaryngol Head Neck Surg 2002;128:161–166.
Kim DD, Dreher MA. The fibula free flap in maxillary reconstruction. Atlas Oral Maxillofac Surg Clin North Am 2007;15:13–22.
Dalgorf D, Higgins K. Reconstruction of the midface and maxilla. Curr Opin Otololaryngol Head Neck Surg 2008;16: 303–311.