Introduction

The preponderance of surgery performed on the oral cavity utilizes a transoral route, such as for dental diseases, chronic tonsillitis, and sleep apnea. However, malignancy will be the primary focus of this chapter, although benign tumors such as ameloblastomas and some congenital and/or traumatic abnormalities can also require an involved surgical exposure. Approximately 70% of the neoplasms occur in dependent portions of the oral cavity, the regions most commonly bathed with food, saliva and tobacco residue. Although this chapter focuses on the surgical approaches to the oral cavity in a framework of the final reconstruction, it is necessary to appreciate the indications for certain approaches based on the primary treatment of a particular disease process.

Throughout treatment planning the extirpative and reconstructive surgeon must communicate to provide the patient with the optimal potential for cure but also the ideal reconstruction, which may provide an improved quality of life. Issues that require pre-operative planning between the extirpative team and the reconstructive team have been discussed in detail in another chapter of this text.

Therapy for benign neoplasia of the oral cavity, as elsewhere in the body, usually entails local excision with minimal, but clear, margins via a transoral approach for all but the largest or recurrent lesions. For malignant neoplasia, the issues of what is an adequate margin and how to manage the draining lymphatics add significant complexity to therapy decisions and surgical approaches. Most advocate at least a 1-cm margin of uninvolved tissue, except that which is adjacent to bone, and many favor 1.5-cm margins around poorly differentiated or less circumscribed lesions, in addition to intra-operative histologic control of such margins via frozen section studies (1-10). For tumor approaching bone, such as the mandible or the hard palate, an uninvolved and intact layer of periosteum is usually deemed adequate (1,3-5,8,10-13). If the periosteum is involved, but the outer table of the adjacent bone is grossly intact, then drilling off the outer cortex of that bone suffices. If a bony cortex is eroded, at least a 1-cm margin of grossly uninvolved bone is required although many prefer 1.5-cm, recognizing that frozen section verification of clear margins is difficult for the pathologist in this densely calcified tissue.

The marrow space can be evaluated by rolling a moistened, cotton-tipped applicator over the tissue for cytologic examination or using a curette to remove the soft marrow tissue for frozen-section analysis. The inferior alveolar neurovascular bundle can also be dissected free from the bony canal and processed for frozen-section analysis. For management of the mandible, most surgeons prefer a marginal mandibu-lectomy (commonly the superior half of the mandible) when the periosteum of the alveolar arch is breached by a mucosal malignancy. In cases of superficial erosion of the mandibular cortex, however, a segmental mandibulectomy is felt to be necessary (1-4,12-17).

For confirmation of adequate soft-tissue margins, the authors prefer the use of intra-operative micrographic mapping of tissue margins (as commonly practiced on cutaneous malignancy; Figs. 1-3) for all T1 or most small T2 verrucous or well-differentiated squamous cell carcinomas of the buccal, lip, or palatal mucosa. Somewhat more selective frozen section guidance of margins is required for larger lesions with deep extent.

More advanced lesions of the oral cavity require a more aggressive surgical approach with exposure beyond which can be achieved through a transoral approach. These more extensive procedures will often be combined with postoperative radiotherapy. It is in these more complex situations that careful evaluation and planning will help determine the appropriate surgical approach to accomplish all the goals of treatment and reconstruction.

Figure 1A-B (A) Via lip split, access to the paramedian mandible is achieved. If osteotomy is desired, a stairstep cut with a side cutting burr or an oscillating saw is accomplished after preliminary placement, and then removal of a mandibular bridging plate. Placement of the osteotomy is commonly through the socket of a lateral incisor, sparing the more deeply rooted canine tooth.

Figure 1A-B (A) Via lip split, access to the paramedian mandible is achieved. If osteotomy is desired, a stairstep cut with a side cutting burr or an oscillating saw is accomplished after preliminary placement, and then removal of a mandibular bridging plate. Placement of the osteotomy is commonly through the socket of a lateral incisor, sparing the more deeply rooted canine tooth.

Figure 1 (B) Intra-operative transoral view of a 3.5 cm verrucous carcinoma of the soft palate, retromolar trigone and adjacent buccal mucosa, less than 5-mm thick.
Figure 2 (A) Prior to mandibular osteotomy, a mandibular bridging plate is placed to assure proper alignment of dentition after the tumor resection.
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