The goals of head and neck reconstruction have been to ensure primary wound healing and to maximize functional restoration while minimizing patient morbidity. During the past two decades, the use of modern microvascular free-tissue transfer has revolutionized the reconstruction of large defects in the head and neck. By enabling reliable one-stage reconstruction, microvascular free-tissue transfer has expanded the limits to which extirpative techniques can reasonably be applied in the head and neck.1 Although, in expert hands, the success of these free flaps is greater than 95% with low morbidity,^2–13 questions regarding their suitability in older patients,^14–18 as well as their cost-effectiveness^{19, 20} and superiority over conventional techniques,^21–28 continue to be raised.

At the Department of Otolaryngology, University of Pittsburgh School of Medicine, we have amassed extensive experience with the use of microvascular free-flap reconstructions of deficits in the head and neck. Our published experience of more than 300 free flaps was one of the largest in the English literature with a greater than 90% success rate and described the factors responsible for the success of free flaps in our institution.² Some of the keys to the consistent success of free flaps in our experience have been appropriate patient selection, choosing the most appropriate flap for each defect, meticulous preoperative and postoperative management, and a close working relationship between the oncologic and reconstructive surgical teams. Although we do not use free flaps in all cases, microvascular free-tissue transfer, when used appropriately, represents the most reliable, cost-effective, and functional state-of-the-art technique for reconstruction of defects in the head and neck.

Flap Selection in the Head and Neck

Distinguishing between patients whose defects can be reconstructed by more conventional techniques and those who would benefit from free-tissue transfer is critical in achieving a successful outcome. Such factors as the size and location of the defect, its complexity, and compromised wound situations attributable to preoperative radiation therapy and infection may predispose to the use of free flaps.¹ For example, we now consider free flaps the most reliable technique for reconstruction of the mandible and full circumferential pharyngeal defects. It is the technique of choice in our department. In other cases, when selecting a method of reconstruction, we give careful consideration to preoperative functional status and to the patient’s expectations. For some patients, the use of skin grafts and regional muscle pedicle flaps continues to play an important role in reconstruction of defects in the head and neck. In each case, success depends on understanding the functional and cosmetic aspects of the defect that will be created and selecting the flap most appropriate for the given site in the head and neck.

ORAL CAVITY

Successful reconstruction in the oral cavity is measured by the ability to restore speech, swallowing, and airway function.²⁹ The ultimate functional outcome is generally influenced more by the volume of soft tissue loss and its reconstruction than by the reconstruction of the mandible.³⁰ The surface of the oral cavity and oropharynx consists of thin, pliable, sensate, lubricated tissue; it should be replaced by similar tissue whenever possible. Bulky tissue is needed only in the area of the base of tongue, where it aids in the oral phase of swallowing.³⁰ The anterior and lateral regions of the floor of mouth are vitally important because of their effect on tongue mobility and in maintaining salivary flow. Studies indicate that as the percentage of oral tongue and base of tongue resected increased, the efficiency of swallowing decreased.³¹

Split-thickness skin grafts are well suited for the reconstruction of defects in the oral cavity and oropharynx unless the resection involves extensive areas of the base of the tongue or mandible. In a recent study of relatively limited resections of the oral tongue (< 30%) and base of the tongue ( < 60%), patients in whom primary closure or skin grafting was used had more efficient swallowing of liquids, less pharyngeal residue, and shorter pharyngeal delay times than were noted in similarly matched patients whose reconstruction involved a free flap.³¹ In our department, split-thickness skin grafting is the technique most often used for reconstructing surgical defects of the tongue, floor of mouth, and buccal and oropharyngeal defects, as well as for re-creating the alveolar sulcus.

For larger defects in the oral cavity, our preferred alternative is the radial forearm flap. This flap is thin and pliable enough to be used in the oral cavity. The radial artery and its venae commitantes are relatively straightforward to harvest and, as the arm is out of the field, the reconstructive team can harvest the flap simultaneously with the resection. Bulky flaps such as the pectoralis myocutaneous (PMC) flap often interfere with mobility of the tongue and flow of saliva, and reliability is variable. In a study of 211 patients who underwent immediate reconstruction with a PMC flap, 63% developed flap-related complications and 26% required reoperation.²⁴ In contrast, the radial forearm flap has had a greater than 90% success rate when used at our department and at other institutions.^2–6 Donor site morbidity with the radial forearm flap consists mainly of partial loss of the skin graft with exposure of the flexor carpi radialis tendon, numbness in the distribution of the radial nerve, and dissatisfaction with the appearance of the skin graft.11 The radial forearm has become the most frequently used flap for reconstruction of the oral cavity at our institution despite these problems.

MANDIBLE

The goals of mandibular reconstruction are to reconstitute the mandibular arch and to allow for dental restoration. The bone available with pedicled flaps, such as the trapezius or scapular spine, is inadequate for dental implantation; moreover, nonvascularized bone heals by slow substitution of bone stock and is not suitable for patients who will need radiation within 6 weeks of surgery.²⁹ For lateral mandible defects that do not involve the symphysis, the criterion for reconstruction with bone remains unclear. Provided that good mobility of the tongue is present, most patients can swallow effectively after segmental resection, even with mandibular drift and malocclusion. In these patients, an expedient option entails either no reconstruction of the mandible or a reconstruction plate covered with a radial forearm flap to stabilize the mandible.^{2, 29} Using this technique, exposure of the plate has been noted in 5% of patients with lateral and posterior defects. In anterior defects, the exposure rate increases to 20%, probably due to the resection of the depressor muscles of the mandible, which permit unopposed retraction of the plate superiorly through the flap.³³

Patients with more extensive resection of the mandible, particularly the anterior segment, must undergo reconstruction in order to restore contour, swallow effectively, and avoid the problems of salivary incontinence. Several flaps have been described for mandibular reconstruction; in our experience, the fibular osteocutaneous flap and the radial forearm osteocutaneous flap have advantages over the iliac crest and scapular flap.² The radial forearm osteocutaneous flap has a more reliable skin paddle than the fibular osteocutaneous flap, but only 30% of the radius can be harvested for bone, and osseointegrated implants are not possible, owing to a lack of adequate bone stock. The radial flap is an excellent choice for straight segmental resections of the posterior body of the mandible and for lateral defects requiring only one osteotomy to reconstruct the posterior body and inferior portion of the ascending ramus.² It is our flap of choice where soft tissue sacrifice in the retromolar trigone, tonsillar fossa, lateral floor of mouth, and hypopharyngeal areas requires reconstruction and bone replacement is desired. The fibular osteocutaneous flap offers up to 25 cm of bone of sufficient height and is specifically indicated for reconstruction of anterior defects, for large defects from parasymphysis to ascending ramus, and for patients requiring eventual osseointegration.²⁹ The major drawback of this flap is the questionable reliability of the overlying skin paddle, which depends on small perforating branches lying in the septum between the peroneal and soleus muscles. The flap has been modified to include a cuff of soleus muscle to improve the reliability of the skin paddle. The major advantage of using free microvascular bone flaps for oral cavity reconstruction is that the chances for bone healing and tolerating radiation therapy are far better than with conventional bone grafts.

PHARYNX AND CERVICAL ESOPHAGUS

Reconstruction of circumferential defects of the pharynx and esophagus has been revolutionized through the use of free flaps. As in other defects of the head and neck, the extent and location of the defect will determine the need for free flap reconstruction. Small defects of the pharynx that spare the larynx can be closed primarily if adequate mucosa is saved. Some defects in the lateral pharyngeal wall may be closed with a pectoralis flap, but swallowing is generally compromised. Defects of the posterior pharyngeal wall usually require a radial forearm or a split jejunal flap, which are not too bulky for closure.³⁰ When the entire circumference of the pharynx and esophagus is resected, the defect is best repaired using a gastric pull-up or free flap to prevent stricture and fistula formation. For circumferential defects below the thoracic inlet, a gastric pull-up is indicated because of the potential for a distal anastomotic leak into the mediastinum if a free flap is used. Contraindications to a gastric pull-up include severe pulmonary disease (because the procedure requires traversing the mediastinum) and hepatobiliary disease. The mortality from gastric pull-up procedures remains significant at 8 to 12%.³⁰

An absolute indication for the use of a free flap includes circumferential defects that extend more superiorly into the nasopharynx. We prefer either the free jejunum or radial forearm flap for defects above the thoracic inlet. The free jejunal transfer has the advantage of almost unlimited length for reconstruction; because mucosal tissue is sutured to mucosal tissue, the problem of anastomotic stricture is reduced. In our department, free jejunal transfer has an overall success of 95%, with successful swallowing achieved in 88% of patients with an average interval until swallowing of 10.6 days.¹ The most common complication has been fistula formation, which has occurred in 15% of patients;¹ however, most of the fistulae healed spontaneously. The mortality rate after a free jejunal transfer is about 5%, which is considerably less than that for a gastric pull-up procedure.³⁰ A consideration in using this flap is that, unlike patients who successfully undergo reconstruction with a gastric pull-up, the large lumen of the jejunal segment may not allow sufficient air for neo-esophageal speech.²⁹ We have routinely performed a tracheoesophageal puncture (TEP) in our jejunal flaps, which has resulted in remarkably good quality of speech despite these concerns. Another consideration is the increased morbidity with laparotomy in obese or elderly patients or in patients who have undergone previous abdominal surgery. In these cases, a fasciocutaneous flap such as a radial forearm or lateral thigh flap should be considered. We prefer the tubed radial forearm flap, as ≤ 20 cm can be harvested with minimal morbidity. Disadvantages of this flap include the presence of hair-bearing skin and a higher incidence of fistula formation than is associated with the jejunal flap, presumably due to the additional longitudinal suture line required to tube the flap. Although the radial forearm flap obviates the need for a laparotomy in medically compromised patients, the jejunal graft remains the gold standard for defects of extensive length.

MIDFACE

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