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Transoral Inferior Maxillectomy
Introduction
The hard palate is the site of origin of benign and malignant tumors. The most common tumor of minor salivary gland origin in this site is pleomorphic adenoma, a benign tumor that appears as a smooth submucosal mass. Approximately 5% of cancers of the oral cavity involve the hard palate and maxillary alveolus. Squamous cell carcinoma accounts for approximately 90% of malignancies of the hard palate and the upper alveolar ridge ( Fig. 32.1 ). Cancers arising in the minor salivary glands are the most prevalent non–squamous cell cancers of the hard palate. Adenoid cystic carcinoma is the most common of the cancers of minor salivary gland origin, followed by mucoepidermoid carcinoma, malignant mixed tumor, acinic cell carcinoma, and other adenocarcinomas. Lymphoma and plasmacytoma also arise on the hard palate. Polymorphic reticulosis (formerly called lethal midline granuloma) commonly involves the hard palate and upper alveolus. Necrotizing sialometaplasia and pseudoepitheliomatous hyperplasia have an appearance similar to squamous cell carcinoma. Malignant melanoma may also occur in the mucosa of the hard palate. Sarcomas of bone and soft tissue have likewise been reported in the hard palate and upper alveolus, more commonly in children.
Evidence of a direct cause-and-effect relationship between tobacco, alcohol, and cancer of the hard palate is not as clear-cut from an epidemiologic point of view as it is with cancer in other upper aerodigestive tract sites. An exception is the high incidence of cancer of the hard palate in parts of India and the Philippines, where reverse smoking is practiced. Poor oral hygiene, mechanical irritation, ill-fitting dentures, syphilis, and even mouthwash have been suggested as other possible causative relationships.
Key Operative Learning Points
- 1.
A thorough examination of the oral cavity, nasal endoscopy, examination of the neck, imaging with maxillofacial computed tomography (CT) scan, and biopsy are essential to fully characterize the lesion, devise a plan of management, and determine the extent of the resection.
- 2.
Comprehensive understanding of the three-dimensional anatomy and surrounding structures will facilitate resection and help to avoid complications.
- 3.
Reconstruction of smaller palatal defects with a prosthesis is sufficient, whereas larger defects will require a local, regional or even microvascular free tissue flap.
Preoperative Period
History
- 1.
History of present illness:
- a.
How was the mass discovered?
- 1)
Incidentally by a dentist or by the patient
- 1)
- b.
How long has the mass been present?
- c.
Associated signs and symptoms
- 1)
Pain
- 2)
Numbness of the palate and face
- 3)
Bleeding from the mass
- 4)
Epistaxis
- 5)
Dental infections, tooth extraction/removal, loose teeth, poorly fitting dentures
- 6)
Trismus
- 7)
Voice change
- 8)
Neck mass
- 9)
Weight loss
- 1)
- a.
- 2.
Past medical history:
- a.
Prior oral lesions removed?
- b.
History of periodontal disease
- c.
Medical history
- 1)
Diabetes, immunosuppression, coronary artery disease, thrombosis, hypertension
- 1)
- d.
Prior head and neck surgery or radiation
- e.
Social history
- 1)
Smoking and alcohol consumption
- 1)
- f.
Family history
- 1)
History of cancer of the head and neck or other malignancies
- 1)
- g.
Medications
- 1)
Anticoagulation/antiplatelet therapy
- 2)
Insulin
- 3)
Homeopathic products
- 1)
- a.
Physical Examination
- 1.
Oral cavity: Using a bright light, tongue depressors, and suction; a thorough examination of the oral cavity is paramount in determining the extent and characteristics of the mass.
- a.
Location
- 1)
Involvement of the hard or soft palate, involvement of lingual or buccal alveolus
- 1)
- b.
Size of mass: Map the area of the tumor including areas of swelling suggestive of subepithelial spread of the tumor.
- c.
Characteristics of the mass:
- 1)
Leukoplakia or erythroplakia lesion
- 2)
Endo- or exophytic mass. Palpation of the mass is clinically the best way of evaluating thickness and depth of infiltration.
- 3)
Submucosal lesion
- 1)
- d.
Dentition: Evaluate for loose dentition, ill-fitting dentures, and gingivitis.
- e.
Examine loose dentition for the possibility of malignant involvement of the tooth sockets and underlying bone.
- f.
Sensation of palate: Numbness of the palate may indicate involvement of the palatal foramina and skull base.
- a.
- 2.
Nasal endoscopy: Detailed inspection of the floor of the nasal cavity, inferior meatus, and lateral nasal wall is essential to determine the presence of intranasal extension of the cancer.
- 3.
Neck: The neck should be examined for the presence of a mass because many patients will present with metastasis to the neck. Evidence of prior surgery should be noted.
- 4.
Cranial nerve examination: Specifically evaluate the distributions of the trigeminal nerve to evaluate for neural involvement by the cancer.
- 5.
Flexible fiberoptic laryngoscopy: Evaluation of the remainder of the upper aerodigestive tract is performed to exclude the possibility of a second primary cancer, because second primaries may occur in 20% to 25% of patients with squamous cell carcinoma of the oral cavity and oropharynx.
Imaging
- 1.
Maxillofacial, neck, and chest CT scan with and without contrast: Identify the size and extent of infiltration of the tumor, any areas of bone invasion, involvement of the nasal cavity and maxillary sinuses, and the presence of metastases to the lymph nodes. CT is also very helpful in diagnosing distant metastases, which occur most commonly in the lung.
- 2.
Positron emission tomography (PET)/CT: This technique is not helpful in the evaluation of the primary cancer, but it may be very helpful in evaluating the neck for metastatic lymph nodes because they may be involved in up to 50% of patients with squamous cell carcinoma of the hard palate. PET/CT scanning is also valuable in detecting the presence of distant metastasis.
Indications
- 1.
Surgery is the first-line treatment of all benign and malignant tumors of the palate.
- a.
Benign tumors may be removed without resecting bone and there is no requirement for reconstruction.
- b.
Malignant tumors will require resection of part or all of the hard palate or maxillary alveolus (or both) to remove bone that is obviously involved along with at least a 1-cm margin. These defects will require some form of reconstruction.
- c.
Adjuvant chemoradiation is beneficial when there is bone invasion, perineural invasion, two or more positive lymph nodes, or extracapsular spread.
- a.
- 2.
Ipsilateral selective neck dissection, levels I to III, should be performed for tumors that do not involve the midline. Bilateral selective neck dissections should be performed for tumors involving the midline.
Contraindications
- 1.
Presence of distant metastasis in the lung
- 2.
Very advanced local disease (T4b) involving the masticator space, pterygoid plates, skull base, or encasement of the carotid artery
- 3.
Severe medical comorbidities
Preoperative Preparation
- 1.
Map out the extent of the tumor based on physical examination and imaging findings.
- a.
Anticipate the extent of the defect to determine whether the patient will require restoration of oral-nasal separation with a dental prosthesis, local pedicle flap, or free flap reconstruction.
- b.
If the dimensions and site of the tumor, whether benign or malignant, require resection of the maxillary alveolus or palatal bone, or both, a plan must be made to achieve oral-nasal separation. In most circumstances this can best be accomplished through the use of an obturator. A prosthodontist should always be consulted preoperatively so that the appropriate dental records and impressions can be taken and a surgical splint fabricated for use following resection of the tumor.
- a.
- 2.
Biopsy: A definitive biopsy is necessary to plan surgical management. Benign and malignant tumors of salivary gland origin may be covered by mucosa, and incisional biopsy is usually necessary in such cases for accurate diagnosis.
- 3.
In the presence of a malignant tumor, determine the need for ipsilateral or bilateral neck dissection.
- 4.
Preoperative medical clearance must be secured for patients with significant medical comorbidities.
- 5.
Counsel the patient regarding the risks of the procedure. Informed consent should include: bleeding; infection; need for local, regional, or microvascular reconstruction; possible use of a dental prosthesis; evaluation by a prosthodontist; and potential cosmetic deformity.
- 6.
Discontinue use of anticoagulation and antiplatelet therapies prior to surgery.
- 7.
Early admission is recommended for detoxification in patients with known alcohol abuse.
Operative Period
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