The maxilla is a complex structure occupying the midface.

Conceptually, it is a six-walled construct (hexahedron) bounded by the orbit superiorly, the palate and oral cavity inferiorly, the nasal airway medially, and the infratemporal fossa and cranial base posteriorly.

Anteriorly and laterally, it forms the contour of the cheek (FIG 1A,B).¹

The maxillary sinus is a mucosa-lined air cavity in the maxillary process that drains into the middle meatus of the nose.

The skeletal framework consists mainly of the maxillary and zygomatic bones, which articulate with parts of the pterygoid, palatine, lacrimal, ethmoid, and sphenoid bones (see FIG 1A).

The vertical maxillary buttresses and the horizontally oriented alveolar process define the contour of the midface, contribute to vertical facial height, carry the dental elements of the upper jaw, and support the upper lip.¹

The soft tissues comprising the skin, lining mucosa, and intervening facial musculature constitute the lower eyelid, the cheek, the upper lip, and oral commissure.¹

From a reconstructive standpoint, it is critical to appreciate that the maxilla forms the floor of the orbit, the roof of the mouth (the palate), and the lateral nasal wall including the lacrimal system.¹

From a functional perspective, its integrity is critical for normal speech, mastication, and deglutition.¹

Anteriorly, it is related to the facial and angular arteries, whereas posteriorly, it is in close proximity to the internal maxillary artery, the pterygoid venous plexus, and the last four cranial nerves.

The zygomatic and buccal branches of the facial nerve ramify in the sub-SMAS plane of the cheek to supply the orbicularis oculi, the orbicularis oris, and the levators of the upper lip (FIG 1C).

The infraorbital nerve travels in the floor of the orbit to emerge on the cheek through the infraorbital foramen and provide sensation to the midface. The zygomaticofacial nerve also appears anteriorly through a foramen inferior to the lateral part of the inferior orbital rim.

Maxillary defects occur in many cases secondary to tumor extirpation of malignancies originating in the paranasal sinuses, the nasal cavity, the palate, or the orbit.

In other cases, aggressive malignancies arising from the intraoral mucosa, the cheek skin, or the salivary glands may invade the maxilla and require extensive composite tissue excisions.¹

High-energy traumatic injuries (eg, gunshot wounds) constitute another cause of challenging maxillary defects.²

Necrotizing inflammations like noma (cancrum oris)³ and malignant pyoderma in association with granulomatosis with polyangiitis have also been described.⁴

Composite resections where lining, support, and external skin are missing can pose a significant reconstructive challenge.

A complete history should be obtained to identify comorbid conditions that may be optimized preoperatively.

Physical examination of the head and neck should evaluate dentition, speech and swallowing, facial nerve function, and sensory innervation.

The expected resection should be envisioned and soft tissue and bony requirements estimated. Close collaboration with the ablative surgeon is crucial in this regard.

Assessment of potential local and distant tissue donor sites should be undertaken (eg, temporalis, pectoralis major, radial forearm, rectus abdominis, anterolateral thigh [ALT] flap).

Imaging modalities like CT scan and MRI are useful preoperatively to determine the size and extent of the tumor and understand the potential resulting defect. These studies are also useful in patients with acquired defects of the maxilla resulting from trauma or infections.

A 3D CT scan helps with preoperative virtual surgical planning and manufacturing of custom-designed models, templates, osteotomy guides, and prebent plates and selection of optimum screw size and site especially if dentoalveolar reconstruction and functional occlusion are contemplated. However, these options are most useful for osseous reconstruction of maxillary defects.

Duplex examination or CT angiography with 3D reconstruction is occasionally required to evaluate the neck vessels in difficult cases with prior neck dissection or radiotherapy.

Postoperatively, positron emission tomography (PET) and CT scan will be of benefit to assess the operative bed for tumor recurrence if a free flap was employed.

Custom-made obturators can be used to manage maxillary defects and can provide support for facial structures and separate the oral cavity from the maxillary sinus.

Obturators restore intelligible speech, prevent nasal regurge, and provide aesthetic contours.

Obturators maybe useful in patients at high risk for complex reconstructive procedures or, on occasion, as salvage of a failed reconstruction.

They may also be useful for small defects of the palate (<50% of the hard palate), providing rapid rehabilitation with no donor-site morbidity.

The use of an obturator requires close preoperative, intraoperative, and postoperative collaboration between the oncologic surgeon, reconstructive team, and a prosthodontist. The steps necessary for obturator creation include:

Use of obturators carries the advantage of visual inspection of the surgical site for tumor recurrence. This benefit, however, remains theoretical because reoperation is infrequent and modern imaging enables early detection. Nevertheless, many patients have been successfully served with these devices.

Disadvantages of obturators include leakage and nasal regurgitation due to imperfect fitting, the need for frequent cleaning and successive refinements as the tissues remodel.

The development of microsurgical techniques enabled successful autogenous tissue reconstruction of complex maxillary and midface defects.

The approach is largely dictated by the extent of the defect and the functional requirements.

Simple defects can be closed with local soft tissue flaps and bone grafts when necessary and rarely pose a problem.

Complex composite defects involving external skin cover, structural support, and lining require planning for restoration of orbital floor support, lining of the nasal airway, palatal reconstruction, and resurfacing of surface defects that may include the upper lips, eyelids, and nose. In addition, dental restoration is necessary in most maxillary resections that involve the hard palate.

In this context, the classification system described by Cordeiro and Santamaria¹ is useful to stratify maxillary/midface defects and evaluate their functional requirements. The resultant analysis is able to guide appropriate treatment strategies.¹ Based on this schema, maxillectomy/midface defects can be categorized as follows:

The advent of vascularized composite allotransplantation (ie, facial transplantation) refined midface and maxillary reconstruction by replacing “like” with “exact like,” thus achieving a closer aesthetic match in terms of soft tissue and skeletal components.

The risks of lifelong immunosuppression nevertheless limit the use of this modality, which is still considered experimental, to a highly select group of patients (eg, trauma).

Gastman et al. published an extension of Cordeiro and Santamaria classification system¹ to address the added specific needs in evaluating patients presenting for facial vascularized composite allotransplantation.⁷