Fig. 21.7 Type IIIb defects: total maxillectomy and orbital exenteration. The resected specimen contains external eyelid, cheek skin, orbital contents including entire maxilla and palate. (Center, left) This creates a large surface area/large volume defect. A three-skin-island rectus abdominis myocutaneous free flap is shown (inset). This flap provides multiple large surface areas with large volume of soft tissue and muscle to fill the defect (center, right). From Cordeiro PG, Santamaria E. A classification system and algorithm for reconstruction of maxillectomy and midfacial defects. Plast Reconstr Surg 2000;80:2331–46. Reprinted with permission

but does not close the palate. This causes a need for an obturator. Reconstruction with a temporalis flap is usually indicated in patients who are older or are not good candidates for a free tissue transfer. In type IIIa resections, if the malar eminence is preserved, there is usually good anterior projection of the upper midface, which obviates the need for anterior maxillary wall reconstruction.

Type IIIb defects are extensive and have large volume and surface area requirements (Figs. 21.7 and 21.8). Of significant importance is that the anterior cranial base, in the area of the sphenoid, is often exposed, meaning that coverage of the brain becomes essential.

21.3.2.4 Type IV Defects

Type IV defects result from orbitomaxillectomy, which involves resection of the upper five walls of the maxilla and the orbital contents and preservation of the palate (Fig. 21.9). Type IV defects are generally large volume and surface area defects. Because the palate is intact, the reconstructive objectives are primarily soft tissue fill and external skin resurfacing, if required. The rectus abdominis flap allows effective accomplishment of all these objectives. Conceptually, these are simple reconstructive procedures; technically, however, they are challenging and best left in the hands of an experienced microvascular free-flap surgeon.

The algorithm of Cordeiro and Santamaria is principally based on the extent of resection of the maxillary bone, which is the key building block of the structure of the midface. First, the bony defect must be addressed; then the associated soft tissue, skin, palate, and cheek-lining deficits must be assessed; and finally the palate, oral commissure, nasal airway, and eyelids need to be addressed individually. The most common walls needing reconstruction to maintain the functional and aesthetic unit

Fig. 21.8 A 75-year-old woman with recurrent maxillary sinus SCCA. She had had a prior partial maxillectomy and underwent a complete bilateral maxillectomy. She was reconstructed with a fibula osteocutaneous free flap. The orbital floors were spared

are the anterior (cheek), superior (orbital floor), and inferior (palate). Bone replacement is essential so that the orbital floor can maintain the position of the globe [1, 9, 14]. Bone replacement is also useful in the maxillary arch to provide anterior projection of the midface and bone stock for osteointegrated implants [15–17]. For reconstruction of the orbital floor, bone grafts can be effectively used in conjunction with soft tissue flaps (free or pedicled) because this area requires minimal supportive strength. Vascularized bone is indicated in the maxillary arch if osteointegration is required and when high-dose postoperative radiation therapy is planned. Free flaps are usually required when skin islands are necessary for intraoral, cheek, palatal, nasal lining, or external resurfacing. The space between the restored anterior, superior, and inferior walls of the maxilla can usually be filled with soft tissue, and the nasal lining may or may not be restored.