Version June 2024
INTRODUCTION — Head and neck cancer involving the mandible or palate is typically treated with surgical resection. Additionally, surgical resection may be required in cases of osteoradionecrosis of the mandible. Trauma and infection may also affect these structures. These defects can cause significant problems with mastication, deglutition, speech, cosmesis, and even airway management due to tongue prolapse.
The goal of surgical reconstruction is to restore presurgical function and cosmesis. Modern reconstructive options, specifically free flaps or free tissue transfer, have greatly improved functional outcomes and patient quality of life. Optimization of mandible and palate reconstructive outcomes often requires a team approach, including prosthodontics and speech pathology.
The basic elements of mandibular and soft palatal reconstruction will be reviewed here. The management of maxillary and hard palate defects is discussed separately, as is rehabilitation for speech and swallowing defects. (See "Management of acquired maxillary and hard palate defects" and "Speech and swallowing rehabilitation of the patient with head and neck cancer".)
UpToDate also has a topic on overview of head and neck reconstruction, which discusses free tissue transfer options for other defects (eg, tongue, parotid, pharyngoesophageal, and base of skull) in addition to the mandible and palate. (See "Overview of head and neck reconstruction".)
TIMING OF RECONSTRUCTION — Reconstruction can be primary (performed at the time of resection) or secondary (performed as a separate procedure after resection). Although primary reconstruction has become the standard of care, it is not always possible to achieve, particularly in resource-limited regions or countries [1,2].
●Primary reconstruction can rapidly restore anatomy and function while decreasing costs, number of operations, duration of hospitalization, and complications compared with secondary reconstruction [2,3]. Because the head and neck patient may have significant comorbid conditions and require adjuvant therapy, quicker recovery and decreased hospital stay are important considerations.
●The delay in reconstruction with a secondary procedure may lead to significant muscle atrophy and fibrosis with contracture of soft tissues. Additionally, patients who undergo secondary reconstruction can ultimately end up with inferior functional and cosmetic outcomes compared with those who undergo primary reconstruction [2,3].
Primary reconstruction at the time of tumor resection is predicated on obtaining free tumor margins. If there is concern regarding residual tumor at the time of initial surgery, it would be advisable to delay reconstruction.
MANDIBULAR RECONSTRUCTION — The goals of mandibular reconstruction include restoration of deglutition, speech, airway support, and cosmesis. In addition, reconstruction must provide adequate strength to support masticatory force and the possibility of future dental implants [4,5]. Restoration of bony continuity is recommended to optimize mastication and speech and to maintain symmetry of the lower third of the face [6]. Reconstruction has positive effects on the quality of life in these patients [7]. (See "Overview of head and neck reconstruction", section on 'Mandible reconstruction'.)
Mandibular defects can involve bone only (such as cases of ameloblastoma or osteoradionecrosis) or bone with soft tissue (such as cases of squamous cell carcinoma). Regarding the bony defect, this can be a partial bone loss (marginal mandibulectomy) or complete bone loss (segmental mandibulectomy). Typically, marginal mandibulectomy can be reconstructed with soft tissue only because the mandible remains intact. In the case of segmental mandibulectomy, a vascularized bone graft (free tissue transfer) is ideally used to replace the lost segment of bone. Lateral mandible defects can be reconstructed with bone and reconstruction plate or with soft tissue and reconstruction plate in the case of an edentulous patient. Anterior mandible defects require bony replacement with reconstruction plate in order to restore lower-third facial symmetry and prevent an "Andy Gump" deformity.
The type of reconstruction required depends upon several factors, including the size of the bony and soft tissue defect, location of the defect (anterior versus lateral), and whether the patient is dentulous or edentulous [4]. The choice of reconstruction is also affected by patient factors such as preoperative morbidities and ability to withstand long operations. Rehabilitation and patient motivation also play roles in the long-term success of reconstruction.
Several mandible reconstructive classification schemes have been developed over the years that are based on anterior versus lateral defects with associated soft tissue loss [8-10].
There are a variety of options for mandibular reconstruction, and each has inherent advantages and disadvantages [5,11-13]. Free tissue transfer (free flaps) of vascularized bone grafts, with or without soft tissue, has become the gold standard of mandible reconstruction over the past 30 years [11,14-16].
Although free tissue transfer techniques require increased operative time, donor site morbidity, and the need for a surgeon trained in microvascular anastomoses, these drawbacks are outweighed by the improved healing and function that can be achieved.
Other approaches to mandible reconstruction include soft tissue flaps (free flap or pedicled regional flap) and nonvascularized bone grafts.
Free tissue transfer (vascularized bone grafts) — Free tissue transfer, also known as free flaps, has become the treatment of choice for mandible reconstruction with success rates of 93 to 99 percent [2,3,17-23]. Free flaps have the following advantages:
●Improved vascularity compared with pedicled grafts and an expanded range of bony and soft tissue options [4].
●Free flaps can accept dental implants that function as tooth root analogs, thereby permitting improved denture stability and retention. This results in superior function and restoration of mastication compared with patients who have not received reconstruction [24].
●Flaps can be transferred with a sensory nerve, which can aid in oral sphincter competence, improved deglutition, and decreased aspiration [4].
Donor sites — The major donor sites for mandibular reconstruction include the fibula, iliac crest, scapula, medial femoral condyle, and radius (table 1) [3,17,25,26].
●Fibula – Since the fibula free flap (FFF) was first described for mandibular reconstruction in 1989 by Hidalgo, it has become the most commonly used vascularized bone graft because of the length and thickness of reliable bone that can be harvested (figure 1) [27-29]. Additionally, a two-team approach can be used. The fibula is nourished by both periosteal and endosteal blood supplies, allowing for multiple osteotomies [30]. Additionally, up to 25 cm of bone can be harvested, which allows for a wide range of mandibular reconstructions across lateral and anterior defects. The rate of flap survival has been reported at 90 to 93 percent [2,29]. An optional skin paddle can be harvested with the flap, but the blood supply can be somewhat tenuous. A contraindication to using this flap is the lack of three-vessel runoff from the anterior tibial, posterior tibial, and peroneal arteries. This is typically assessed preoperatively with color flow doppler and/or angiogram [31,32].
●Osteocutaneous radial forearm – The osteocutaneous radial forearm free flap (OCRFFF) is another option used by some surgeons because of the reliability of the skin paddle, long pedicle length, and overall flap success rate [29,33]. In a multicenter comparison between scapula, FFF, and OCRFFF, the authors reported that the OCRFFF had the lowest perioperative complications, including fistula, flap loss, and 30 day readmission rates [29]. Up to 10 to 12 cm of length and up to 40 to 50 percent of the width of the radius can be harvested [33,34]. Following harvest, the radius must be prophylactically plated with a specialized compression plate to prevent pathologic fracture, a dreaded complication that was prevalent prior to adoption of prophylactic plating [34,35]. Because of the limitations in length and width of bone, this flap is perhaps best utilized in single-segment reconstructions for edentulous patients since the bone cannot typically accommodate dental implants.
●Scapula – The scapula free flap is considered the most versatile flap because it provides the options of bone, muscle, and multiple soft tissue sources based off the subscapular system. Therefore, this flap can provide a large amount of soft issue coverage for large and complex defects, including those involving the palate. The lateral border of the scapula and scapular tip are both bony options with separate arterial supplies coming off the subscapular artery. Together, greater than 10 cm of bone can be harvested. Additionally, there are multiple muscle (latissimus and serratus) and skin paddle options. Classically, the main disadvantage to this flap has been the need to flip the patient in order to access the donor site, thereby increasing operative time [33]. However, a technique for harvesting the flap in the supine position to allow a partial two-team approach has been developed [36]. Another potential downside to this flap is the limited bony stock to allow for dental rehabilitation, with some studies showing better results in male patients with the scapula tip free flap [37,38]. This flap is a good option in patients with poor lower extremity vascularity preventing use of the fibula.
●Iliac crest – The iliac crest free flap offers good bone stock and allows superior mandibular height. The native shape of the iliac crest is similar to a mandible, and osteotomies are potentially not required. The iliac crest also offers the best bone stock for osseointegration of dental implants. Flap harvest requires release of the abdominal musculature to access the properitoneal space [39]. As a result, patients may complain of acute pain, ventral (abdominal wall) hernia formation, and long-term sensory disturbances [5,39].
Soft tissue graft (free tissue transfer or regional flap) — These grafts consist of either soft-tissue-only free tissue transfer or pedicled, regional soft tissue grafts. They are used in conjunction with a bridging reconstruction plate to typically reconstruct lateral mandible defects and are best suited for patients who are edentulous; have large, complex soft tissue defects; are unable to withstand additional operative time for an osseous free tissue transfer; and/or have poor prognoses [10,14,40]. A soft tissue free flap with reconstruction plate can maintain dental occlusion and facial contour while avoiding the morbidity associated with harvesting a bone-containing free flap [41,42].
Soft tissue free flap options include the anterolateral thigh, radial forearm, rectus abdominis, and latissimus dorsi (table 2) [14,40]. The pectoralis major is typically the regional flap of choice. In a small study comparing mandible reconstruction using a soft tissue free flap versus pectoralis major regional flap, the authors reported a significantly higher rate of plate extrusion and longer hospital stay with the pectoralis flap [10]. In a separate study of soft tissue free flaps, the authors found that soft tissue flaps that overcompensated for the defect were five times less likely to extrude the plate compared with conventional soft tissue replacement [40]. In a comparison of soft tissue free flaps versus osteocutaneous free flaps, the authors reported similarly low rates of plate extrusion (5 percent for soft tissue and 4 percent for osteocutaneous) [14].
Nonvascularized bone grafts — Nonvascularized bone grafts (NVBGs), typically taken from the rib or iliac crest, have a limited role in mandible reconstruction since vascularized bone grafts (free tissue transfer) became widely adopted. NVBGs can be used in small mandibulectomy defects (<5 to 6 cm) that have not been irradiated, because the graft relies on a healthy, recipient tissue bed [43,44]. They may also be used in patients who are too medically compromised to tolerate the additional operative time required for a free flap procedure. Potential complications of NVBGs include bone resorption, inadequate soft tissue coverage, infection, and loss of stabilization [45]. Compared with vascularized bone grafts, nonvascularized bone grafts result in lower rates of bony union (69 versus 96 percent), higher numbers of operations, and less successful dental rehabilitation (82 versus 99 percent) [43].
Reconstruction plates — Reconstruction plates have been used to bridge mandibular defects alone and in conjunction with vascularized soft tissue coverage or vascularized bone grafts.
In a study comparing stainless steel, titanium, and titanium hollow screw reconstruction plates [46], both titanium reconstruction plates were preferred because of their potential for osseointegration and fewer screws being needed for sufficient fixation. Stainless steel had the highest rate of complications. Titanium plates are now typically used in reconstruction.
Currently, main centers are using virtual surgical planning and computer-aided design to create reconstruction plates and cutting guides for osteotomies based off preoperative imaging [47-49]. In the future, plates may be fabricated on site with laser printing [50]. Virtual surgical planning can increase the accuracy of shaping the graft intraoperatively and decrease operative time [51].
SOFT PALATE RECONSTRUCTION — Postsurgical defects may interfere with the physiologic function of the soft and hard palate and result in problems with deglutition and speech; these include velopharyngeal insufficiency and rhinolalia (hypernasal speech) when the soft palate is involved.
Function of the palate — The hard palate functions as a barrier between the oral and nasal cavities, aids in articulation, and assists in food processing. The function of the soft palate can be divided by anatomic region [52]:
●The anterior soft palate is relatively fixed and slung from the posterior edge of the hard palate.
●The middle soft palate containing the muscular bulk of the palate is where the levator action is most marked and is involved mostly in speech.
●The posterior soft palate is involved in deglutition.
The soft palate and base of the tongue come together while chewing to hold food in the oral cavity. Depression of the soft palate prevents food from prematurely entering the oropharynx and may even increase the size of the nasal airway to help in breathing during oral intake of food [53]. If the patient loses the ability to apply the palate to the base of the tongue, inefficient transport of food may occur. This may result in problems with coordination and timing of relaxation of the upper esophageal sphincter and failure of laryngeal closure, leading to pooling of food contents and aspiration [54].
Closure of the velopharynx as the soft palate reaches the posterior pharyngeal wall prevents nasal regurgitation by ensuring that food or liquid does not enter the nasal cavity. Velopharyngeal closure is accomplished by elevation of the soft palate, anterior motion of the posterior pharyngeal wall, and medial movement of the lateral pharyngeal wall [55]. The action of the posterior pharyngeal wall, in an effort to maintain palatopharyngeal closure, is exaggerated in patients with palatal insufficiency [56].
Speech may also be adversely affected by a palatal defect. Without a partition between the oropharynx and nasopharynx, vocalization may be transmitted through the nasal cavity as opposed to the oral cavity, which leads to rhinolalia. Articulation of the sounds "k" and "g" and the sibilant sounds "s" and "z" requires a functional soft and hard palate, respectively [56,57].
Treatment of palatal defects — Surgical reconstruction, dental prostheses (obturator), or a combination of both can be used to remedy palatal defects. The type of reconstruction or rehabilitation depends upon the size and location of the defect, the baseline medical condition of the patient, dentition, and the goals of the patient. The prosthodontist and surgeon must work together as a team. (See "Overview of head and neck reconstruction", section on 'Mandible reconstruction'.)
The patient should undergo complete preoperative counseling and discussion of options, as well as formation of dental impressions [58]. Not only may the patient be more likely to adjust to the emotional changes caused by the postsurgical defect, but immediately after surgery, they may be fitted for a prosthesis that can aid in speech and swallowing and offer structural support [58].
Obturators — An obturator is a dental prosthesis used to close an oronasal defect of the hard or soft palate. Obturators are more successfully used in defects of the hard palate. Because the defect is bound by the soft palate and remaining hard palate, there is little movement of the boundaries, and the obturator is more easily stabilized. As much hard palate tissue must be preserved as is oncologically safe in an effort to save the premaxilla and key teeth, especially the canine. These structures give the obturator improved support [59]. (See "Management of acquired maxillary and hard palate defects", section on 'Obturators'.)
With a soft palate obturator, the goal is to provide a barrier from the nasal cavity and posterior pharynx when appropriate. The obturator must leave space posteriorly for nasal breathing at rest and must be abutted by the posterior pharynx and lateral pharyngeal walls to close the defect [58]. It can also be used after free flap reconstruction of the soft palate to hold the flap up against gravity [60].
The dentate status of the patient and the decision to use a prosthesis may affect the surgical resection [58]:
●If more than one-half of the soft palate needs to be resected for tumor-free margins in a dentulous patient, the entire soft palate should be removed since the small amount of retained soft palate may interfere with obturator function.
●If the patient is edentulous, the goal is to save as much soft palate as possible because it may aid in stabilization of the obturator. Edentulous mouths are more difficult to treat with a prosthesis due to limited tissue for prosthetic stability.
Surgical reconstruction — Because of its dynamic motion, soft palate defects are particularly challenging to reconstruct. Surgical reconstruction can be accomplished with local, regional, or free flaps [15,60-62]. Partial-thickness defects typically can heal by secondary intention. In the case of small defects (<25 percent) involving only the soft palate, primary closure can be used [60,63].
●Local flaps move adjacent tissue within the oral cavity and pharynx to fill in the defect. Various local flaps can be used in defects involving up to 50 percent of the soft palate [60,63]. The pharyngeal flap is a common option in posterior defects that can be combined with another local flap, but it can potentially cause nasopharyngeal stenosis and obstruction [60,63,64]. The superior-constrictor advancement-rotation flap (SCARF) achieves circumferential closure of the velopharynx and reestablishes its valvular sphincteric function [65]. The uvulopalatal flap is appropriate for small defects of the lateral soft palate. The facial artery musculomucosal flap, made up of buccal mucosa and buccinator muscle, can also be used for lateral defects [66]. The palatal island flap is another option as well [67].
●Regional flaps are an option in patients with larger defects or previously irradiated tissue. The temporalis and temporoparietal fascia flaps, as well as the pectoralis muscle flap, have been used [53,64,68]. The pectoralis flap can be used for oropharyngeal defects, including the palate. Bulk, hair-bearing tissue and chest asymmetry are potential problems that may be decreased by raising only the muscle of the flap, not the overlying skin [54,69]. Even with muscle only, the weight of this flap can be an issue for palatal reconstruction. The temporalis flap or temporoparietal fascia flap can be used for palate reconstruction [68]. In the case of the temporalis flap, there is an associated cosmetic defect at the donor site. Loss of the temporal branch of the facial nerve is a possibility when raising these flaps [70].
●Free tissue transfers have been used for large or total soft palate defects, primarily using the radial forearm free flap [62,63]. This flap is a popular option due to the thinness and pliability of the tissue. It is perhaps the best reconstructive option for the soft palate [54,62,63]. The anterolateral thigh free flap is also an option but is a bulkier flap, and its use may depend upon the extent of the defect beyond the soft palate [62].
The fibula and scapula free flaps are options when the defect extends into the hard palate and maxilla where bony reconstruction may be needed [54,71]. The fibula flap has the advantages mentioned above and is especially valuable when a small skin paddle is needed with a bone segment for maxillary support or midface reconstruction [72]. The scapula flap is an excellent option for complex defects involving multiple subunits, including the maxilla and mandible, because of its various chimeric bone and soft tissue options [15,73]. (See 'Donor sites' above.)
For further discussion of the management of maxillary and hard palate defects, see the related topic. (See "Management of acquired maxillary and hard palate defects", section on 'Management approach'.)
SOCIETY GUIDELINE LINKS — Links to society and government-sponsored guidelines from selected countries and regions around the world are provided separately. (See "Society guideline links: Head and neck cancer".)
SUMMARY
●Surgical reconstruction after resection of head and neck cancer – The goal of surgical reconstruction is to restore presurgical function and cosmesis. Primary reconstruction, rather than a secondary procedure, has become the standard of care. (See 'Timing of reconstruction' above.)
●Mandibular reconstruction – Mandibular reconstruction aims to restore mastication, deglutition, and cosmesis. Free tissue transfer represents the state of the art in head and neck reconstruction and offers a wide range of tissue options for optimal outcomes. Although free tissue transfer techniques require increased operative time, donor site morbidity, and the need for a surgeon trained in microvascular anastomosis, these drawbacks are outweighed by the improved healing and function that can be achieved. (See 'Mandibular reconstruction' above.)
●Palatal reconstruction – Postsurgical defects may interfere with the physiologic function of the soft and/or hard palate and result in problems with deglutition and speech. The associated physiologic defects vary depending upon the particular region of the hard or soft palate involved, and reconstruction must be directed accordingly with surgery or obturator. (See 'Soft palate reconstruction' above.)
ACKNOWLEDGMENT — The UpToDate editorial staff acknowledges Michael R Zenn, MD, FACS, who contributed to earlier versions of this topic review.
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