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and need for IMF, plate fixation and/or intermediate splint and need for IMF, plate fixation and/or intermediate splint

Abbreviation: IMF, intermaxillary fixation.

always preferable to perform an en bloc resection that minimizes the chances of tumor seeding and allows histologic verification of margins on permanent section studies after specimen decalcification. Gross mandibular invasion, however, necessitates a segmental resection and some form of defect reconstruction that can range from a metal bridging plate to a vascularized osteocutaneous free-tissue transfer (13,15,16,18,19). In such cases, a transcervical (or "external") approach, in addition to the transoral exposure, is usually required. The risk of occult cervical metastases or clinical or radiographic evidence of adenopathy also mandates some form of external approach in addition to the transoral exposure of the primary tumor, with or without postoperative irradiation (10,20-23). The choice of a surgical approach and subsequent reconstruction of the oral cavity will be influenced by the plan for management of cervical nodal disease. The cervical lymphatics at greatest risk for metastatic disease are the Level I regions for primary lesions of the lips, anterior floor of mouth (FOM), anterior third of the tongue, the gingiva, and the buccal and hard palatal regions. The Level II regions are the primary at-risk site for the remainder of oral cavity locations (Fig. 4). The appropriate lymphatics should be

Figure 4 Lymphatics that drain the oral cavity structures (lower lip, anterior FOM and tip of tongue to submental nodes; upper lip, buccal region, lateral FOM and mobile tongue to perivascular facial or submandibular nodes; remainder of oral structures and the aforementioned nodal regions into jugulodigastric or level II nodes). Abbreviation: FOM, floor of mouth. Source: From Ref. 28.

Figure 4 Lymphatics that drain the oral cavity structures (lower lip, anterior FOM and tip of tongue to submental nodes; upper lip, buccal region, lateral FOM and mobile tongue to perivascular facial or submandibular nodes; remainder of oral structures and the aforementioned nodal regions into jugulodigastric or level II nodes). Abbreviation: FOM, floor of mouth. Source: From Ref. 28.

addressed either surgically or with post-operative radiotherapy when the risk of metastasis exceeds 20% or when clinical nodal disease is evident (1,2,5,10,12,2426). This will certainly be the case for most T2 and larger oral cavity malignancies, and for some earlier lesions. For tumors originating at or crossing the midline, both sides of the neck are at risk for metastatic disease and should be addressed (7,16,2022,27,28). In the salvage surgery situation, the surgeon must err on the aggressive side of management as the lymphatic drainage pattern of a neoplasm is not as predictable after irradiation or surgery as before such and the patient is unlikely to have a curative option should the salvage fail (1,2,9,16). Tumor extirpation takes precedence over preservation of form and function, when the oncology surgeon manages the care of any particular patient. However, recent advances have increased the options for surgical access and reconstruction without compromising cure, with cosmetic and functional factors becoming increasingly important in the determination of the extirpative approach. Mandibular integrity is preserved when there has been no gross penetration of the mandibular cortex by tumor, and if an osteotomy is required, such as for a mandibular swing access, the osteotomy is preferentially placed anterior to the mental foramen to preserve sensation to the ipsilateral lip, and only one tooth is sacrificed at the mandibulotomy site (preferably not the functionally important canine tooth) (14,15,29).

It is critical to place the patient in proper maxillomandibular relationship by intermaxillary fixation, intermediate splint, or with pre-osteotomy plating of the mandible with rigid fixation. A helpful adjunct at the time of osteotomy is to preserve a flap of gingivae at least 1-cm proximal or distal to the osteotomy to place over the osteomy site at the conclusion of the procedure to prevent fistula formation and nonunion.

Preservation of the lingual, hypoglossal, and marginal mandibular nerves are routine unless such are directly involved with the tumor. If perineural propagation of the tumor is in question, resection of 1-cm of the nerve closest to the tumor is essential with subsequent frozen-section analysis. Then, mobilization of the proximal and distal segments of that nerve is required for a reanastomosis should there be no perineural invasion. Any of the aforementioned nerves can easily be mobilized sufficiently, without tension on the suture line, to make up for a 1-cm defect.

Preservation of the facial artery and vein becomes relevant should a platysmal myocutanous or submental island flap be part of the reconstructive option, and ample stumps of those vessels are routinely tagged by the extirpative surgeon to allow the reconstructive surgeon ready access to such vessels should a free flap be selected.

It is important to remember that any artery or vein of sufficient caliber (including external jugular vein, superior thyroid artery, facial artery and vein, and transverse cervical artery and vein) should not be ligated if possible during the neck dissection or tumor extirpation to preserve flow for possible free-tissue transfer. If ligation is mandated, an atraumatic vascular clamp may be placed at the proximal stump to avoid clotting within the vessel during the remainder of the procedure. At least 2-cm of vessel should be preserved if possible and additional length is beneficial particularly for flaps reaching superior to the hard palate.

With resection of a large tumor, reformation of the supporting elements of functionally important oral structures must be re-established, such as the tongue to the inner surface of the anterior mandibular arch or of the larynx to the inferior mandible (if the digastric and mylohyoid muscle and/or stylohyoid ligament suspensory elements have been disrupted).

Prior to beginning a resection, the extirpative surgeon needs not only to plan an oncologically sound ablation of the primary tumor, and of any draining lymphatic regions if the chance of metastasis is greater than 20%, but also should plan to minimize disruption of uninvolved structures and to minimize cosmetic deformity and functional impairment where feasible. With such considerations prior to the ablation, the reconstructive team has not only the requisite field of clear margins, but also the maximum spectrum of rehabilitative options.

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