Management of acquired maxillary and hard palate defects

INTRODUCTION — Head and neck cancer and its treatment can cause significant difficulties in orofacial function and thus impair quality of life. When surgery results in a maxillary defect, morbidity can be due to nasal regurgitation (food, liquid, and sound) through the defect, loss of teeth and the inability to chew properly, malnutrition, impaired speech, and distortion of the facial appearance. Severe psychological issues can be a secondary consequence of these complications.

The approach to managing maxillary defects, including both the use of a prosthesis (obturator) and surgical reconstructive techniques, will be reviewed here. The management of soft palate and mandibular defects is discussed separately. (See "Mandibular and palatal reconstruction in patients with head and neck cancer".)

GOALS OF TREATMENT — The goal of treatment is to restore function (mastication, swallowing, speech) and a normal appearance to the face. This may be accomplished either through artificial closure of the defect using an obturator prosthesis or through surgical reconstruction of the defect.

To do this requires:

●Closure of the defect between the oral and nasal/sinus cavities

●Provision of a stable base for dentition and for the maxilla to occlude with the mandible, thus allowing proper chewing of food

●Restoration of the facial appearance, including midface projection and symmetry

●Support of structures superior to the maxilla, especially the orbit, to prevent visual disturbances

Optimal management requires preoperative multidisciplinary input from a head and neck surgeon, a maxillofacial surgeon, a maxillofacial prosthodontist, and a speech pathologist. Patient-specific factors (including an assessment of patient preferences, comorbidities, support network), along with the tumor type, prognosis, and specific anatomic defect, need to be considered in choosing a therapeutic approach.

FUNCTIONAL ANATOMY AND CLASSIFICATION OF DEFECTS — Understanding the anatomy of the maxilla is critical for the management of these patients. The maxilla can be divided into supportive buttresses and processes (figure 1).

●The supportive buttresses of the maxilla are essential for resisting the mechanical forces associated with mastication. The restoration of these structures is essential to providing a stable occlusal surface with the mandible. Furthermore, the maxillary buttresses allow for an even distribution of forces across the skull base.

●The zygomatic, alveolar, palatine, and frontal processes are responsible for the form of the palate and midface.

The extent of maxillary defects is a critical factor in choosing the optimal therapeutic approach. This may include the use of an obturator prosthesis or surgical reconstruction. Although tumor staging systems provide important prognostic information regarding specific primary sites for head and neck cancers, a more detailed classification of the resulting specific anatomic defects is necessary for planning postoperative rehabilitation [1]. These defects can be divided into several categories (figure 2):

●Class Ia – Central defects of the palate that do not extend laterally to involve the tooth-bearing alveolar ridge.

●Class Ib – Central defects with limited involvement, or posterior involvement of just one alveolar ridge.

●Class II defects – Involvement of no more than one-half of the palate or less than 50 percent of the palate if bilateral defect is present.

●Class III defects – Involvement of both sides of the palate and with involvement of more than 50 percent overall.

●Class IV defects – Involvement of the suprastructure of the palate.

●When relevant, defects are also classified by the extent of vertical involvement to reflect involvement of the orbit, zygomatic body, overlying skin, or exposure of the intracranial contents.

MANAGEMENT APPROACH — A team of specialists experienced in the treatment of maxillary defects should assess the patient and discuss the advantages and disadvantages of alternative approaches so that patients can arrive at a decision to improve their function and quality of life after surgery and rehabilitation. This reconstruction team would include a head and neck surgeon, a maxillofacial surgeon, a maxillofacial prosthodontist, and a speech and swallowing therapist.

The primary objective of surgery for head and neck cancer is the complete eradication of the tumor, which requires adequate surgical margins to reduce the risk of local recurrence. Adjacent structures are resected if necessary to obtain negative margins. Within these constraints, strategically placed teeth, uninvolved bone, and as much of the mucosa covering the hard palate as possible should be retained.

Obturator prosthesis, surgery, or a combination of these approaches may be used to manage the defect. The traditional approach to the management of any residual communicating defects in the hard palate and maxilla relied upon the use of a prosthetic obturator to occlude the defect and thus restore speech and swallowing. However, the functional success that can be achieved with obturators decreases with increasing size of the defect. Advances in surgical techniques have led to the incorporation of surgery into the management of these patients, even into some patients with some smaller defects.

Obturator versus surgery — Multiple factors need to be considered in choosing the optimal postoperative management approach for patients with an acquired maxillary defect. In addition to the specific details of a defect and the tumor itself, these include patient-specific factors (including patient preferences, comorbidity, support network) and the availability of appropriate expertise.

●Small defects (class I) (figure 2) can generally be managed with an obturator prosthesis. In this setting, an obturator is generally stable and well tolerated. The use of an obturator provides immediate rehabilitation without the need for further surgery. However, some patients may find the need to maintain the prosthesis inconvenient. For small defects, surgical reconstruction using a soft tissue flap (eg, radial forearm free flap) may provide a viable alternative.

●For patients with larger defects (class II), an obturator prosthesis may be a reasonable option, but results are less predictable compared with smaller lesions. As the size of the defect increases, and conversely the remaining dental arch length and palate surface areas decrease, the stability of the prosthesis can decrease. Surgical reconstruction may be preferred but may require bone (ie, vascularized bone-containing free flap) to provide adequate support [2].

●For large defects (class III and IV) – When the defect is more extensive, a more complex surgical reconstruction is required, and this generally requires vascularized bone-containing free flaps. Such reconstructions require a second operative site (eg, fibula, iliac crest, scapula, radius), but this method of orodental rehabilitation can achieve superior functional and quality of life outcomes compared with defect-matched patients rehabilitated with a prosthetic obturator [3].

Obturators — Functional restoration of the maxillectomy defect with an obturator prosthesis utilizes the remaining palate and dentition to support, stabilize, and retain an obturator bulb in place. A pressure-resistant seal of the obturator bulb against the lateral mucosal lining and skin graft helps with retention and stability to restore speech and swallowing.

Prosthetic rehabilitation is optimal when the size of a defect is small enough that the remaining structures can stabilize the prosthesis over the defect. Instability of the obturator results in air and fluid leakage through the nasal cavity and thereby compromises function [4-6]. When an obturator prosthesis is to be used, there are three phases in the management of a palatomaxillary defect:

●Surgical obturator – A surgical obturator is fabricated prior to surgery, with the primary objective of allowing the patient to resume oral nutrition, speech, and swallowing functions immediately after the ablative procedure. The surgical obturator generally will remain in place for at least 7 to 10 days after surgery. After this time, the surgical obturator is removed and either the prosthesis is modified or an interim obturator is fabricated.

●Interim obturator – An interim obturator is used for at least two to three months after surgery to allow for healing prior to placement of the permanent (definitive) obturator. A longer time period is often required if surgery is followed by radiation therapy and/or chemotherapy. The interim obturator is designed as a removable device with clasps on the remaining dentition. If desired, it can provide tooth replacement after surgery. Patients are educated for insertion and removal as well as daily hygiene and maintenance.

●Permanent (definitive) obturator – Once adequate tissue healing has occurred, the interim obturator is removed and replaced with a permanent obturator. The definitive obturator will provide tooth replacement as part of the prosthesis if the dental arch was included in the resection.

Surgery — Surgical reconstruction is an important alternative to the use of a permanent obturator. The timing of surgical reconstruction requires a careful consideration of disease and patient-specific factors.

Primary surgical reconstruction at the time of definitive tumor surgery obviates the need for an interim obturator to restore and maintain function. Immediate reconstruction may not be appropriate or feasible in all cases due to a number of factors, such as the adequacy of surgical margins or an excessive length of the procedure.

Reconstruction of the maxilla may require reconstitution of the hard palate, lateral nasal wall, alveolus, and anterior face of the maxilla. In some situations, reconstruction of the zygoma and orbital floor is required as well. These structures are responsible for both cosmetic and functional characteristics of the midface. Reconstitution of the buttress system and attention to the processes ensure a stable base for occlusion, which is essential to optimal functional and aesthetic rehabilitation.

Advances in surgical techniques at other sites in the head and neck region are now being applied to reconstruction of palatomaxillary defects. Microvascular surgical techniques with free flap surgery allow the transfer of muscle, connective tissue, skin, and bone to recipient sites [7-12]. Smaller defects are amenable to either adjacent tissue transfer such as a pedicle flap ("palatal island") or radial forearm free flap soft tissue reconstruction. Large defects are best reconstructed with vascularized bone-containing free flaps (VBFFs). A vascularized bone free flap of choice for maxillary reconstruction is likely to be harvested from the fibula donor site. However, consideration to other donor sites may include harvest from the scapula and iliac crest regions. 

FUNCTIONAL OUTCOME ASSESSMENT — Functional outcome assessments can be made with subjective or objective instruments. A patient questionnaire, or subjective testing, can investigate symptoms or effects of a disease process, treatment, and quality of life.

The assessment of quality of life in head and neck cancer survivors is discussed separately. (See "Health-related quality of life in head and neck cancer".)

SUMMARY

●Sequelae of head and neck cancer surgery – When surgery for a head and neck cancer results in a maxillary defect, morbidity and impaired quality of life can be due to nasal regurgitation through the defect, loss of teeth and the inability to chew properly resulting in malnutrition, impaired speech, and distortion of the facial appearance.

●Goals of treatment – The goal of treatment is to restore function and a normal appearance to the face. This may be accomplished either through artificial closure of the defect using an obturator prosthesis or through surgical reconstruction of the defect. This includes closure of the defect between the oral and nasal cavities; provision of a stable, functional base for dentition; and restoration of the facial appearance. (See 'Goals of treatment' above and 'Obturators' above and 'Surgery' above.)

●Management approaches – Optimal management and the choice of a specific approach requires preoperative multidisciplinary input from a head and neck surgeon, a maxillofacial surgeon, a maxillofacial prosthodontist, and a speech pathologist. Patient-specific factors (including an assessment of patient preferences, comorbidities, and support network) need to be considered, along with the tumor type, prognosis, and specific anatomic defect, in choosing a therapeutic approach. (See 'Management approach' above.)

•Smaller defects can be managed with an obturator prosthesis or by soft tissue reconstruction with adjacent tissue transfer (eg, pedicle flap) or a radial forearm free flap.

•Large defects are best reconstructed with vascularized bone-containing free flaps, most commonly from the fibula donor site. (See 'Management approach' above.)

ACKNOWLEDGMENT — The UpToDate editorial staff acknowledges Jean-Francois Bedard, DMD, and Joseph Toljanic, DDS, who contributed to earlier versions of this topic review.