Introduction to and classification of midface resections

Tumors of the midface can arise in the maxillary sinus, palate dentoalveolar structures or ethmoid sinuses. These can be isolated to their specific origin or spread to adjacent areas.
The extent of both the approaches and the reconstructive methods largely depend on the amount and location of hard and soft tissues involved.

Osteotomies are designed to allow for entire tumor removal with a rim of normal tissue surrounding it. Typically 1-2 cm margins are adequate.

The midface presents unique challenges with a complex 3D anatomy, multiple specialized sites, and no singular technique to achieve an optimal result.

Common challenges in midface reconstruction include:

• Oronasal and oromaxillary fistulae
• Sinus communication
• Loss of tooth-bearing segments
• Loss of lip, cheek, and orbital support
• Loss of midface projection
• Impaired phonation
• Impaired oral alimentation
• CSF fistulae

Return to a good quality of life depends on a successful reconstruction and rehabilitation. To achieve a successful reconstruction of the midface, several key principles to minimize the likelihood of perioperative complications, and restoration of anatomical boundaries and barriers should be followed.

Key elements are:

• Consistently obtain a healed wound
• Seal the palate
• Separate the intracranial and extracranial cavities when barrier is lost
• Reconstruct the orbito-zygomatic complex
• Restore speech and swallowing
• Restore an acceptable cosmetic appearance
• Restore functional dentition

The reconstruction options range from prosthetic (obturator) to the use of regional or free tissue transfers. Patient selection and timing of intervention are critical for successful reconstruction. These patients also require the care of a multidisciplinary team.

The most important element is to use tissues with robust blood supply. Although there are a variety of options, choices can be made based on the following principles:

• Safety
• Reliability
• Single stage procedure
• Minimal donor site morbidity
• No interference with adjuvant treatment and post-op surveillance
• Tissues must tolerate the burden of healing related to:
• Radiation therapy
• Previous chemotherapy
• Poor vascularization
• Local contamination

These defects can be classified based on their horizontal and vertical components. Several classification schemes exist in literature. In this project, the Brown classification [1] will be utilized.

[1] Brown JS, Rogers SN, McNally DN, Boyle M (2000) A modified classification of the maxillectomy defect. Head & Neck; 22 (1); 17-26.

Brown class I
There are two types of defects in this class:

• Alveolar defect without oro-nasal or oro-antral fistulae

• A defect in palatal bone without alveolar defect

Brown class II
Alveolar and antral wall defect, not including orbital floor and rim.

This class is again subdivided depending on the involvement of the alveolar maxilla and hard palate.

a) Unilateral
b) Bilateral (incomplete)
c) Complete

Brown class III
Alveolar and antral wall defect including the orbital floor. Periorbita and skull base may or may not be involved.

This class is again subdivided depending on the involvement of the alveolar maxilla and hard palate.

a) Unilateral
b) Bilateral (incomplete)
c) Complete

Brown class IV
Alveolar and antral wall defect including the orbital floor and content. Skull base may or may not be involved.

This class is again subdivided depending on the involvement of the alveolar maxilla and hard palate.

a) Unilateral
b) Bilateral (incomplete)
c) Complete