Management of Leukoplakia

During the carcinogenic process, some abnormal clonal populations of mucosal cells form clinical premalignant lesions. These are manifested as leukoplakia or erythroplakia. Leukoplakias are common lesions in smokers and patients with a previous history of head and neck cancer. These are also noted in patients without heavy carcinogenic exposure. In general, dysplastic leukoplakia should be treated while lesions harboring only hyperplasia and hyperkeratosis may be observed. Clinical characteristics of lesions suggesting the presence of dysplasia include large size, tongue or floor of the mouth location, red color, friability, and the patient's prior history of oral cancer or dysplasia. It should be emphasized that any lesion which is red or red-speckled (erythroplakia) is of the highest risk for dyplasia or carcinoma and should be biopsied.

Treatment of dysplastic leukoplakia is generally surgical. While the vitamin A analogue isotretinoin (13 cis--retinoic acid or Accutane™) has been shown to be effective in the treatment of dysplastic oral leukoplakia, most lesions will recur after therapy has been stopped and many patients do not tolerate the mucocutaneous toxicity of isotretinoin treatment. 2122

Small dysplastic leukoplakia lesions may be easily excised in the office under local anesthesia with millimeter margins. All excised leukoplakia should be submitted for histopathologic assessment. Laser excision of oral leukoplakias can also be accomplished with good hemostasis and little tissue reaction.23 Other treatment options for leukoplakia include destruction by electrodesiccation, and cryotherapy with liquid nitrogen. Local recurrence is common and occurs in up to one-third of cases.24

Tongue cancer may spread along the mucosal surface to involve the floor of the mouth and the mandible, or the oropharynx, or it may spread by deep invasion between muscle fascicles which offer little resistance to tumor spread (Figure 5-7). It is

SURGERY FOR ORAL CANCER

The lip is the most common site for oral cancer. It is usually considered separately from cancers of other oral subsites as it behaves more like skin cancer. It occurs in sun-exposed surfaces and more commonly on the lower lip than upper lip. It is usually diagnosed early due to bleeding and a visible ulcer. Large lesions may rarely invade the mandible or the mental nerve and foramen.

T1 and T2 lesions are usually cured by wedge resection of the lip with primary closure, (Figure 5-6) although primary radiation therapy is also highly effective. Large T3 or T4 lesions require resection of involved tissues, bilateral upper neck dissections, complex reconstruction, and postoperative radiation therapy.

Depending on the size of the mouth and the presence of dentition, up to 50 percent of the lower lip can be resected and closed primarily in three layers with care to close the orbicularis oris muscle securely. Re-approximation of the vermilion line is important cosmetically. If greater than 40 to 50 percent of the lip is to be resected an Abbe or Estlander lip switch reconstruction borrows lip tissue from the normal upper lip. Karapandzic advancement flaps can also be useful for large lip reconstructions.25 Free flap reconstruction is sometimes necessary but always inferior cosmetically and functionally due to the lack of orbicularis oris function and difficulty with commissure reconstruction.26

The anterior two-thirds of the tongue is the most common site of primary lesions accounting for 40 percent of oral cancers. Most malignancies occur on the lateral borders and ventral surface but are occasionally confined to the tip or the dorsum. Even small lesions of the oral tongue are visible and usually symptomatic, so oral tongue lesions tend to present in earlier stages: 37 percent stage I, 34 percent stage II, 21 percent stage III, and 8 percent stage IV27

Lateral Wedge Resection The Tongue

Figure 5--6. A to C, Wedge resection of lower lip carcinoma with primary closure in layers.

Figure 5--6. A to C, Wedge resection of lower lip carcinoma with primary closure in layers.

Reiki Tongue Figures
Figure 5-7. The anatomical routes of spread of oral tongue cancer.

easy to underestimate the deep extension of tongue tumors and great care should be exercised to take more than 1 cm cuff of normal tongue musculature as the margin of surgical resection. The midline raphe of the tongue does not provide any substantial resistance to tumor spread for lesions approaching or crossing the midline.

Peroral resection is the most common approach for T1 and T2 lesions of the oral tongue (Figure 5-8). A partial glossectomy is easily performed using electrocautery to maximize hemostasis. A 1 to 1.5 cm margin of normal tongue tissue is maintained in all dimensions, and both visual assessment and palpation of the tongue guide the resection. Intraoperative margin specimens for frozen section are taken with a scalpel to minimize cautery artifact. Resection can be performed with a carbon dioxide laser. Whenever feasible, the resection is planned in a transverse wedge fashion. Intraoperative frozen sections of the margins are mandatory. The defect of a partial glossectomy is closed in the horizontal direction causing a foreshortening of the tongue. The appearance and function after horizontal closure are excellent. This is preferable to a longitudinal closure, which results in a thin pointed tongue. The size and the extent of the tumor will determine the orientation of the resection.

For many T2 and T3 oral tongue tumors, and for any sized tumor in the posterior portion of the tongue or floor of mouth, the mandibulotomy approach provides the exposure required to perform an oncologically sound resection. The low morbidity of paramedian mandibulotomy is always preferred to the poor visualization and inadequate assessment

Low Cheek Flap Oral CancerLabiaplasty Modified Wedge Resection

Figure 5-8. A to C, Peroral wedge excision and primary closure of a T1 cancer of the tongue with horizontal closure.

Lower Lip Wedge Excision

of the deep and posterior margins that result from inappropriate peroral excision.28 29 In addition, the majority of these patients benefit from staging elective supraomohyoid neck dissection, which provides the neck exposure needed for the mandibulotomy approach (Figure 5-9).

This procedure begins with elective supraomohy-oid or modified radical neck dissection, in which the skin and muscle flaps of the neck are raised exposing the lower border of the mandible. The floor of the mouth is exposed via the submandibular triangle. Next the lower lip splitting incision is performed. The vermilion border is marked to ensure accurate realignment, and the lip is split sharply in the midline and connected with the anterior extent of the neck incision. The periosteum of the mandible is left undisturbed while the soft tissues of the lip and cheek are elevated to identify and preserve the mental nerve. The gingival mucosa and periosteum are incised at the mandibulotomy site anterior to the mental foramen and lateral to the insertion of the digastric muscle. The cut is planned either between the lateral incisor and the canine tooth, or directly through the root of a lateral incisor tooth that is extracted. Cuts between tooth roots may damage both roots and both teeth may be lost subsequently. Prior to performing the bone cut, the 4-hole reconstructive plates for the lateral and inferior margin of the mandible are molded and the screw holes drilled to ensure accurate realignment. The cut is performed at right angles to the alveolar ridge and angled 45 degrees anteriorly below the tooth roots for better stabilization. Taking care to avoid the lingual nerve, the floor of mouth mucosa and mylohyoid muscles are divided posteriorly up to the anterior tonsillar pillar, and one centimeter from the medial aspect of the mandible.28 Appropriate tumor resection is performed through the exposure thus provided (Figure 5-10).

The reconstruction requires the floor of mouth incision to be closed in layers, and the bone re-approximated with the preformed plates and screws (Figure 5-11). The lip is closed meticulously in three layers with attention to the orbicularis oris muscle and the exact apposition of the vermilion border. The best reconstructive options for partial and hemiglos-sectomy are primary horizontal closure if the defect is not too large, or free flap reconstruction. Other options include closure by secondary intention, split-thickness skin grafting and pedicled flaps. After large resections of the oral tongue, patients require speech and swallowing therapy for functional recovery.

Every effort should be made to achieve negative margins with the initial resection. Intraoperative positive frozen-section margins in tongue surgery significantly reduce local control and survival, even when additional resection and ultimately negative frozen and permanent sections are obtained.30 When intraoperative positive frozen sections occur it reflects a tumor biology that is more invasive and aggressive than is estimated by the surgeon and thus warrants consideration of postoperative radiation therapy.

Final histopathology report of margins may show foci of premalignant change, carcinoma in situ (CIS), close surgical margins (less than 5 mm) or the presence of microscopic foci of invasive cancer. The presence of any of these findings at the surgical mar

Lip Split MandibulotomyMandibulotomy
Figure 5-10. The mandibulotomy approach to tumors of the posterior oral cavity. Biplane fixation of the mandible is necessary.

gin increases the risk of local recurrence twofold, and significantly increases the mortality from oral cancers. Any of these histologic findings suggest a role for postoperative radiation therapy.31,32

Early tongue cancers demonstrate occult spread to the cervical lymph nodes in 20 to 30 percent of cases. The frequency of metastasis is related to the T stage and depth of invasion of tongue cancers. Increasing T stage correlates with increasing incidence of metastatic disease. A depth of invasion by tongue cancer of greater than 5 mm is associated with an increased incidence of occult metastasis.33 Tumor depth greater than 2 mm is correlated with significantly lower sur-

Leukoplakia

Figure 5-11. The mandibular osteotomy is fixed using miniplates which provide accurate dental occlusion, and stability.

vival and control of disease in the neck. In a study of early staged cancers of the tongue and floor of the mouth, the 5-year survival of patients with thin lesions was greater than 95 percent, while survival of patients with thick lesions was less than 80 percent, regardless of T stage (Table 5-2).34 An appreciation of tumor depth can aid in the decision to perform elective neck dissection. Except for oral cancers less than 2 mm thick, all early staged oral cancer patients should receive elective supraomohyoid neck dissection (SOHND). On the other hand, elective radiotherapy to the neck should be employed if radiation therapy is the treatment selected for the primary tumor.

Survival after treatment for tongue cancers has improved over the last 15 years, due to the use of combined modality treatment for advanced disease, and the aggressive treatment of the neck in early stage disease. Franceschi reported 5-year survival of 82 percent for patients treated between 1978 and 1987 with stage I and II disease and 49 percent for

Table 5-

-2. THICKNESS OF ORAL CANCER PREDICTS

SURVIVAL AND TREATMENT FAILURE

Tumor Thickness

5-year Disease Specific Survival (%)

Treatment Failure (%)

< 2mm 2-8mm >8mm

97 83 65

2 45

Data from Spiro RH, et al. Predictive value of tumor thickness in squamous cacinoma confined to the tongue and floor of the mouth. Am J Surg 1986,152:345-50.

Figure 5-11. The mandibular osteotomy is fixed using miniplates which provide accurate dental occlusion, and stability.

Data from Spiro RH, et al. Predictive value of tumor thickness in squamous cacinoma confined to the tongue and floor of the mouth. Am J Surg 1986,152:345-50.

stage III and IV disease. These are improvements over the survival rates in their experience from the period 1967 to 1978 (Figure 5-12).27

The floor of the mouth is the second most common subsite accounting for 20 percent of oral cancers. Due to its dependent location, carcinogens may pool in the floor of mouth leading to high rates of cancer. Because of the small size of this area, floor of the mouth lesions often extend to involve the tongue and the mandibular gingiva. The size distribution of floor of mouth cancers at the time of diagnosis is 30 percent T1, 37 percent T2, 19 percent T3, and 14 percent T4.28 Forty-one percent of patients present with regional neck metastasis, and micrometastases are identified histologically in 17 percent of elective neck dissection specimens. Of all treatment failures, 21 percent recur locally, 37 percent recur in the neck and 29 percent at both sites. Staging elective suprao-mohyoid neck dissection is appropriate for all but very superficial T1 lesions of the floor of the mouth, and bilateral staging neck dissection is indicated for midline lesions. Finally, survival for floor of mouth lesions is 88 percent, 80 percent, 66 percent, and 32 percent for disease of stages I to IV respectively.35

Because of the frequent involvement of the mandible by floor of the mouth tumors, management of the mandible is an important aspect of planning resections of the floor of the mouth. The key clinical question is: does the mandible require resection, and if so how much—the periosteum, a marginal mandibular resection or a segmental resection? Management of the mandible depends on the lesion's proximity to the mandible, whether the mandible is dentate or edentulous, the degree of atrophy of the alveolar ridge, whether the mandible has been irradiated, and whether there is mandibular invasion.

Historically, a segmental mandibular resection was often performed not only for bone involvement by cancer, but also to accomplish a monobloc resection of the primary carcinoma with cervical lymph nodes. It was incorrectly presumed that lymphatics from the oral cavity passed through the periosteum of the mandible to the neck and that in-transit metastasis could be resected with the mandible. The elegant histologic work of Marchetta and col-leagues36,37 has conclusively demonstrated that the lymphatic drainage of the tongue and floor of mouth does not pass through the mandibular periosteum nor through the substance of the mandible.

An additional advantage to routine mandibular resection in decades past was improved access and visualization of oral cancers. However, the morbidity and reconstructive challenges of segmental mandibulectomy led surgeons to reconsider the indications for this procedure, and to explore the possibility of partial-thickness mandibular resections. In these procedures only the alveolar ridge and/or the lingual plate of the mandible is resected (marginal mandibulectomy), and the inferior alveolar artery and nerve and the continuity of the mandibular arch are spared. In order to justify the oncologic soundness of marginal mandibulectomy, studies were undertaken to understand the routes of invasion and spread of cancer in the mandible. The results allow a rational approach to management of the mandible in oral cancer.

McGregor and colleagues have reported that the primary route of SCC invasion of the edentulous mandible is through cortical deficiencies of the occlusal surface of the bone.38 The route of spread in the dentate nonirradiated mandible is via the tooth sockets, and the presence of teeth is a relative barrier to tumor infiltration. Also, the dentate mandible has a greater height from the floor of the mouth than does the edentulous mandible due to the resorption of the alveolar ridge after tooth loss. Therefore, tumors of the floor of the mouth must advance farther up the gingival mucosa to reach the occlusal

Figure 5-12. Graph demonstrating improved survival in tongue cancer from the years 1967 through 1978 to the years 1978 through 1987. Data from Franceschi et al. Improved survival in the treatment of squamous carcinoma of the oral tongue. Am J Surg 1993;166:360-5.

Stage l-ll UI-IV

Figure 5-12. Graph demonstrating improved survival in tongue cancer from the years 1967 through 1978 to the years 1978 through 1987. Data from Franceschi et al. Improved survival in the treatment of squamous carcinoma of the oral tongue. Am J Surg 1993;166:360-5.

Tongue Cancer Surgery Reconstruction
Figure 5-13. The routes of spread of oral cancer to the mandible in the dentate and edentulous mandible.

surface of the dentate mandible than the edentulous mandible (see Figure 5-13).

Cancer invasion of the irradiated mandible occurs not only through the occlusal surface but also directly through cortical bone of other surfaces.39 This suggests the loss of barrier function of the periosteum after irradiation.

In both radiated and nonirradiated mandibles, the spread of squamous carcinoma within the cancellous bone is generally directed inferiorly toward the inferior alveolar nerve canal. Brown and colleagues reported that the early phase of mandibular invasion is erosive and that this phase progresses to an infiltrative phase as the depth of invasion increases.40 In the histologic studies by McGregor and McDonald, tumor spread proximally and distally within the can-cellous bone of the mandible was observed to be no farther than 5 mm beyond the region of overlying soft-tissue involvement, suggesting that a 5 to 10 mm bony margin, beyond the extent of the soft-tissue tumor, is oncologically sound.40 On the other hand, invasion of the alveolar canal by oral cancer allows extensive perineural spread. By this route, disease can travel distally or proximally to the skull base, but does not tend to seed the bone along the course of the nerve or form skip lesions. Invasion of the ramus via the body of the bone occurs readily, especially in the irradiated mandible.41

With these principles in mind, one can develop a rational approach to management of the mandible in oral carcinoma. Because the dentate mandible is relatively resistant to cancer infiltration by adjacent lesions, marginal resection of the alveolar ridge and/or the lingual plate, sparing the alveolar artery, is sometimes acceptable treatment for disease in proximity to the bone. First, the proximity of the tumor is assessed by observation, palpation, and by CT scan if the lesion is fixed to the bone. If the tumor is greater than 1 cm away from the bone, then no mandible resection is needed. If the tumor is less than 1 cm from the mandible, then a marginal resection of the mandible will ensure 1 cm margins. If the tumor involves the gingival mucosa and the periosteum without clinical or radiologic evidence of cortical or cancellous bone involvement, then a marginal resection of the mandible is satisfactory, because any sub-clinical bone involvement is likely to be localized to the alveolar process. If the tumor is fixed to the occlusal surface with clinical or radiologic evidence of cortical or cancellous bone involvement, then a segmental resection is performed because, once the occlusal cortex is breached, there is no barrier to the vertical spread of tumor through cancellous bone to the alveolar canal. Totsuka and colleagues published studies showing that marginal mandibular resection was safe for some tumors with minimal gross bone invasion if there was a histologically "expansive" rather than "infiltrative" pattern of invasion. However, this pattern of invasion was not readily predictable based on radiographic findings.4243

When extensive involvement of the cancellous bone is noted, the alveolar nerve must be assessed by frozen section, and further resection along the course of the nerve to the inferior alveolar foramen, the mental foramen, or the skull base is considered.

Contraindications to marginal resection of the mandible include gross involvement of the cortical or cancellous bone of the mandible, inability to preserve the inferior alveolar artery, significant resorption of the mandible—suggesting very thin and weak residual bone, a previously irradiated mandible, and cancer abutting the mandible on more than two surfaces.

Small T1 lesions that are 1 cm from the mandible are amenable to wide local excision via the peroral approach. This is easier in the edentulous patient due to better visualization. The mucosal margin is at least one centimeter. The deep margin is just below the sublingual salivary gland for superficial lesions. Wharton's duct may be ligated, but the authors prefer to reroute the duct to the posterior edge of the resection if the submandibular gland is not resected in the neck dissection. Caution is taken to identify and preserve the uninvolved branches of the lingual nerve as anesthesia of the tip of the tongue will result from their sacrifice. Small defects may be closed primarily but many can be allowed to granulate and heal by secondary intention. A split-thickness skin graft is an excellent reconstruction for small defects in the floor of mouth that expose the mylohyoid muscle.

Excision of small lesions of the floor of the mouth may require local resection with en bloc marginal resection of the mandible (Figure 5-14).44 This may be accomplished via a peroral approach. The mucosal and soft-tissue excision is left attached to the mandible, the extraction of teeth at sites of alveolar cuts is performed, and the bone cuts are performed with the sagittal saw and ultra-thin blades. Smooth cuts rather than right-angle cuts are favored to evenly distribute forces of mastication and pre

Mouth Cancer

Figure 5-14. Resection of floor of the mouth cancer with marginal mandibulectomy.

Floor Mouth Resection
Figure 5-15. Segmental resection of the mandible through a lower cheek flap approach for a large floor of the mouth carcinoma with gross mandibular bone involvement.

vent subsequent fractures. When the dentate mandible is encroached upon by tumor at the lingual plate only, a vertical partial mandibular resection can be accomplished using the tooth roots as the vertical plane of resection. The related teeth are extracted and the right-angle saw blade is used to resect only the lingual plate, exercising caution to preserve the alveolar artery. Elective or therapeutic neck dissection improves the exposure of the lower mandible. The specimen is delivered en bloc. The resulting defects of the floor of the mouth and the mandible can be left to granulate, however mucosal advancement flaps or a split-thickness skin graft can often close these defects well.45,46

Most T3 and T4 floor of mouth cancers require extended local resections including partial glossec-tomy or a segmental mandibular resection, which is performed through a lower lip splitting incision and a lower cheek flap exposure (Figure 5-15). The mental nerve is sacrificed. An elective or therapeutic neck dis section is always indicated in surgical treatment of large floor of the mouth tumors and this provides good inferior exposure for the resection of the mandible. Tooth extractions and gingival mucosal incisions are then performed. Mandibular reconstruction plates may be pre-bent and screw holes drilled. With the soft-tissue portion of the tumor well defined and protected, the bone cuts are performed with the sagittal saw and the specimen removed en bloc, often with the neck specimen attached as well.44 A frozen-section assessment of the alveolar nerve is prudent. Reconstruction of lateral mandibular defects with reconstruction plates or free bone grafts requires excellent soft-tissue coverage with myocutaneous flaps although the failure rate is 50 percent. Exposure of reconstruction plates used for anterior arch reconstruction approaches 100 percent. The free tissue transfer of fibula with attached muscle and skin is the state of the art reconstruction for large composite resections, especially when the anterior arch is involved.

An alternative surgical approach to T3 and T4 floor of the mouth lesions that do not require segmental mandibular resection is the transcervical pull-through procedure.47 The primary tumor specimen is delivered into the neck with or without marginal mandibular resection. Bilateral upper neck dissections are usually performed. If necessary a marginal or lingual plate resection of the mandible is accomplished. The remaining soft-tissue attachments to the mandible, including the mylohyoid muscles, are divided and the oral contents delivered inferiorly into the neck. This provides good visualization of the tumor for the remainder of the soft-tissue resection. It is critical that the oral tissues are properly re-suspended and that the remaining extrinsic tongue musculature is appropriately attached to the mandible for postoperative swallowing function.

Maxillary and mandibular gingival lesions are often reported in the literature together as gingival lesions. Surgically, lesions of the mandibular gingiva and retromolar trigone are similar and will be discussed together. Lesions of the maxillary gingiva are surgically similar to those of the hard palate and so these two subsites will subsequently be addressed.

Three-quarters of gingival lesions involve the mandibular alveolus and one-quarter involve the maxillary alveolus. A report of 283 mandibular alveolar lesions from Memorial Sloan-Kettering Cancer Center showed the distribution of these primary tumors to be 30 percent T1, 48 percent T2, 17 percent T3 and 11 percent T4.48 Only 5 percent were resected without bone, 32 percent were amenable to marginal resection and 63 percent required segmental bone resection. Local recurrence was 25 percent when the mandible was initially involved with tumor. Occult neck metastasis was found in only 6 of 107 elective radical neck dissections, indicating a low incidence of occult neck disease compared to tumors of other subsites of the oral cavity. Staging elective suprao-mohyoid neck dissection is indicated for T2 or larger lesions in conjunction with segmental mandibular resection. Five-year survival for all alveolar cancers was 77 percent stage I, 70 percent stage II, 42 percent stage III, and 24 percent stage IV.

Overholt49 reviewed the M.D. Anderson Hospital experience of 155 mandibular alveolar lesions and determined that parameters affecting local control and survival were: size greater than 3 cm, bone involvement, and positive surgical margins. As discussed above, marginal mandibular resection is appropriate for periosteal involvement and segmental resection indicated when the cortical bone is involved with cancer.

Peroral wide local resection with marginal mandibular resection can be performed for smaller lesions, while segmental resection requires lip splitting incision and lower cheek flap elevation as described previously.

Tumors of the retromolar trigone occur with a disproportionately high frequency considering the small surface area (Figure 5-16). Fifteen percent of oral cancers occur in the retromolar trigone. This site is difficult to assess clinically because of its posterior location, mucosal irregularity, small area, and visual interference by the dentition. Trismus, if present, may also inhibit the examination, and is indicative of pterygoid involvement. Retromolar lesions are relatively difficult to treat because they spread early to deep structures such as the ascending ramus of the mandible, pterygoid muscles, the masticator space, and the skull base. Another avenue of local spread is the foramen of the inferior alveolar nerve into the ramus of the mandible. Tumor may also spread proximally along the perineurium or within the nerve to the trigeminal ganglion and the CNS. Surgical access to this region is challenging. Bone resection is nearly always indicated, and recurrence is difficult to diagnose.

Figure 5-16. An exophytic lesion in the retromolar trigone.
Bloc Resection Mandible
Figure 5-17. Bone cuts for marginal and conservative segmental resections of the mandibular ramus and body.

The peroral approach to the retromolar region is rarely satisfactory due to the posterior location of the trigone and the necessity for bone resection since the periosteum or bone is usually involved with cancer. Often a segmental resection of the ascending ramus of the mandible and part of the pharynx is necessary. Mandibular rim resection of the molar alveolus and the ascending ramus of the mandible is acceptable for small lesions without gross bony involvement. Marginal mandibular resection of the ascending ramus through the open mouth is not satisfactory.

If bone is grossly involved by clinical or imaging evaluation, then segmental resection of the ramus and/or body is required. If superficial involvement of the molar alveolus or ascending ramus is identified, then conservative segmental mandibular resection sparing the condyle and a posterior strut of ascending ramus is satisfactory bone resection.41 Cuts are performed through the mandibular notch and the coronoid process (Figure 5-17). The alveolar foramen and nerve are included in the resection. Intraoperatively, a frozen-section margin on this nerve is important. Assessment of the superior extent of the disease, including the coronoid process of the mandible, the temporalis muscle, maxillary tubercle, masticator space, and pterygomaxillary space is necessary. Marginal resection of the maxil lary alveolus or partial maxillectomy may be necessary if they are involved with cancer.

Soft-tissue reconstruction with primary closure, or healing by secondary intention over the retromo-lar trigone is occasionally satisfactory. Posteriorly-based buccal mucosal random-pattern rotational flaps, soft palate, tongue, and masseter muscle flaps are all described for this area. The need for thin tissue here suggests an advantage for skin grafting and radial forearm free flap reconstructions. If the ramus is sacrificed, a bulkier pectoralis pedicled flap may cover reconstructive hardware but tends to pull infe-riorly with time. The excellent bone stock of the fibular free flap is detracted from by its association with bulky muscle, and variable survival of the overlying skin paddle. It is infrequent today that a lateral mandibular defect is left unreconstructed, but this defect is tolerated well by many patients and it allows easier assessment of the region for recurrence. Defects that are small, posterior and occur in the edentulous patient are tolerated well.

Carcinomas of the hard palate (Figure 5-18) and upper alveolus are relatively uncommon, accounting for 10 percent of oral cancers,50 except in areas of Southeast Asia where reverse smoking is prac-ticed.51 In the United States, carcinoma of the hard palate is only half as common as carcinoma of the soft palate52,53 and carcinoma of the maxillary alveolar ridge is only one-third as common as carcinoma of the mandibular alveolar ridge.48 These areas are lined with adherent keratinized mucosa, which pro-

Effects Smoking Alveolar
Figure 5-18. Squamous cell carcinoma of the hard palate.

vides protection from the trauma of mastication, and may provide relative protection of the basal nuclei from the effects of carcinogens.

Histologically, carcinomas of the upper alveolar ridge are nearly all squamous cell carcinomas, but up to one-third of hard palate cancers are of minor salivary gland origin.54 In contrast to squamous cell carcinomas, palatal minor salivary gland tumors are often submucosal masses rather than ulcerative or fungating mucosal lesions. Kaposi's sarcoma can be seen on the hard palate of patients with acquired immunodeficiency syndrome. Malignant melanoma of the oral cavity, while rare, occurs most frequently on the palate.

Lesions of the maxillary alveolar ridge are symptomatic, thus allowing early diagnosis. Eighty-two percent of maxillary alveolar ridge carcinomas are T1 or T2 at the time of diagnosis, and 86 percent are N0.48 Palatal carcinomas tend to be larger when diagnosed but only 13 percent have regional metastases when diagnosed.49 The presence of regional metastases to the neck or locally advanced disease decreases 5-year survival from approximately 70 percent to approximately 30 percent.53

Surgery is the treatment of choice for cancer of the maxillary alveolus and the hard palate, and it is frequently necessary to resect periosteum and bone in order to ensure an adequate margin. The mucosa and the underlying periosteum are fused in this region forming a mucoperiosteum. Invasive carcinomas of this area frequently involve the periosteum or the underlying bone, thus reducing the effectiveness of primary radiation therapy for these lesions. However, postoperative radiation therapy for aggressive minor salivary gland malignancies or advanced squamous carcinoma is recommended.5455

T1 and T2 lesions may be amenable to peroral wide local excision with resection of the involved mucoperiosteum and usually the underlying bone. Mucosal incisions are performed with electrocautery, allowing a 1 cm margin of normal tissue. Teeth are extracted at the osteotomy sites, and bony cuts are performed with an oscillating saw. Many small defects granulate well and close by secondary intention. Primary closure is usually not possible due to the immobility of the surrounding adherent mucosa. A posteriorly-based buccal mucosa flap

Orbital Rim Lesion
Figure 5-19. Bone cuts for subtotal maxillectomy preserving the inferior orbital rim and floor of the orbit.
Buccal Mucosa Flap
Figure 5-20. The Weber-Ferguson incision and its subciliary and brow extensions for maxillectomy.

with random blood supply is effective in closing lateral palatal and alveolar defects. A flap of the palatal mucoperiosteum, based on the greater palatine artery in the posterior aspect of the hard palate, can be rotated to cover a small defect, and the donor site left to granulate or be skin grafted. If the nasal and antral mucosa are intact after the resection, the oral defect can be closed with a local flap with a low risk of oronasal fistula formation.

T3 or T4 cancers with invasion of the maxillary antrum or nasal cavity often require partial or subtotal maxillectomy. Advanced lesions invade the nasal cavity, maxillary sinus, the pterygomaxillary space, pterygoid plates and skull base. T3 and T4 cancers requiring subtotal maxillectomy (preservation of the infraorbital rim and floor of the orbit ) (Figure 5-19) need exposure via an extended Weber-Ferguson incision and an upper cheek flap for maximum exposure (Figure 5-20), or exposure via the midface degloving approach. A midface degloving approach provides excellent exposure for anterior lesions involving the lower maxilla and nasal cavity bilaterally without any external incisions, but superior exposure is limited above the orbital rim.5657 After the exposure is obtained, the soft-tissue cuts and dental extractions are performed as needed. Alveolar cuts should be made through the sockets of extracted teeth and not between them. This allows good bony support for the remaining teeth that will bear considerable forces from dental rehabilitation. The following cuts are performed using the oscillating saw: (1) from the lateral maxillary wall to the infraorbital rim preserving the latter, (2) from the infraorbital rim to the nasal cavity through the lacrimal fossa, (3) from the nasal cavity through the alveolar ridge, and (4) through the hard palate (see Figure 5-19). The remaining cuts are the lateral nasal wall cut, which joins the lacrimal cut to the nasopharynx using a thin osteotome and Mayo scissors, and finally the posterior cut. The posterior cut is performed only after all other aspects of the maxilla are freed. This is because significant bleeding can occur from the pterygoid venous plexus and the internal maxillary artery after this cut is performed. The expedient removal of the specimen and prompt packing of the maxillectomy defect are necessary to adequately control bleeding. The final cut is made anterior to the pterygoid plates if the posterior wall of the antrum is not involved, and posterior to the ptery-goid plates if the posterior wall and the pterygomax-illary space are involved with cancer. The cut is made using a curved osteotome and the heavy curved Mayo scissors under palpation guidance with cognizance of the proximity of the internal carotid artery in the deep aspect of the parapharyngeal space, and the apex of the orbit superomedially. Hemostasis is obtained, the lacrimal sac is tacked open with chromic suture and/or the lacrimal duct cannulated with silastic tubing, and the cavity is skin grafted. The graft is supported by packing with xeroform gauze, which is supported by a preformed dental obturator that is wired to the remaining maxillary teeth or the alveolar bone.

Only rarely is total maxillectomy (including the orbital rim and floor) or radical maxillectomy (including orbital exenteration) necessary for oral cavity cancers.

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