Total Glossectomy

Introduction

Total glossectomy is used for advanced cancers of the tongue, mostly squamous cell, either as a primary surgical resection or as salvage following previous (chemo)radiation when partial glossectomy will not achieve adequate resection margins. A key clinical decision is whether a laryngectomy is required. This decision is based on whether a patient is likely to cope with some degree of aspiration and whether extension of cancer into the pre-epiglottic space requires a laryngectomy to achieve an adequate margin. Total glossectomy may incur significant morbidity relating to speech, mastication, swallowing, and in some cases, aspiration. Therefore many centers elect to treat advanced cancers of the tongue with chemoradiation and to reserve surgery for treatment failures.

I consider total glossectomy to be a good primary treatment for advanced cancer of the tongue, provided that patients are carefully selected and that the surgical and reconstructive steps described in the following text are followed to optimize function and quality of life.

Patient selection is critical, both for favorable oncologic and functional outcomes. The majority of patients require a combination of surgery and postoperative (chemo)radiation; hence there is little point in embarking on surgery if a patient is unlikely to complete postoperative adjuvant therapy. To give properly informed consent, patients must have the ability to consider the potential oncologic benefits of surgery against the morbidity relating to speech, dietary modification, mastication, deglutition, and aspiration. If the larynx is to be preserved, then patients must have sufficient cardiopulmonary reserve to cope with some aspiration. As many such patients are malnourished, patients should be assessed from a nutritional perspective to determine whether they are suitable to undergo such surgery. Synchronous primaries or cervical and distant metastases must be excluded by clinical examination, chest radiograph or computed tomography (CT) scan of the lungs, panendoscopy, and PET-CT.

Before contemplating total glossectomy, the surgeon must be confident of being able to achieve clear surgical margins, especially if doing a salvage operation, and the patient should not have known distant metastases. Determine whether the cancer of the tongue is resectable; it may be difficult to assess the extent of the primary cancer due to pain, tenderness, and trismus. If in doubt about resectability, then proceed to image the cancer with CT and/or magnetic resonance imaging (MRI) or even examination under anesthesia.

A number of major nerves are in close proximity to the tongue; examine the patient for neurologic deficits of the hypoglossal, mental, inferior alveolar, and lingual nerves caused by perineural invasion. Widening of the inferior alveolar canal on mandibular orthopantomography (panorex) may suggest involvement of the inferior alveolar nerve. MRI may demonstrate perineural invasion. Should there be evidence of perineural invasion, then the affected nerve must be resected proximally until a clear surgical margin is obtained on frozen section.

Preoperative planning relating to the mandible is important because the cancer may extend across the floor of the mouth to involve the periosteum, invade the inner cortex, or involve the medullary bone. If only the periosteum is involved, then a marginal mandibulectomy (removal of cortical bone) may suffice. After the cortex is invaded, then segmental mandibulectomy is required. However, after the medulla is invaded, then segmental or hemimandibulectomy is done that includes at least a 2-cm length of mandible on either side of visible cancer. Although panorex or CT scan will show gross bony destruction, MRI is preferred to assess involvement of medullary bone. Should marginal mandibulectomy be considered, then the vertical height of the mandible should be assessed clinically or by panorex to predict whether a free composite flap is required.

The next major decision to make is whether total laryngectomy is required. Laryngectomy is indicated in patients who are unlikely to tolerate a degree of aspiration and when the cancer extends to the pre-epiglottic space and/or epiglottis ( Fig. 29.1 ). Whether a patient can tolerate aspiration depends on his or her physical fitness, pulmonary reserve, cognitive function, and attitude, all of which should be considered when selecting patients for total glossectomy, especially if it is to be followed by chemoradiation. Pre-epiglottic space involvement is diagnosed radiologically on CT or MRI (sagittal views) or intraoperatively by palpating for thickening of the pre-epiglottic space between a finger placed in the vallecula and a finger placed on the skin of the neck just below the hyoid bone ( Fig. 29.2 ). If in doubt, the patient has to be consented for possible total laryngectomy based on intraoperative surgical and frozen section findings.

Patients with advanced cancer of the tongue generally have poor dentition and should have preoperative dental radiographs done and either be referred to a dentist or have carious teeth removed at the time of surgery to prevent subsequent osteoradionecrosis.

Finally, the reconstructive team must plan how best to reconstruct the tongue defect and possibly the mandible. Although many techniques are used, it is essential to select a bulky flap to create a convex floor of mouth that bulges up to the hard palate to avoid pooling of secretions and to facilitate articulation and swallowing.

Key Operative Learning Points

• Careful patient selection is the key to maximizing oncologic and functional outcomes.

• Intubation may be difficult.

• Temporary tracheostomy is essential.

• Perform panendoscopy to rule out synchronous primaries.

• Marginal mandibulectomy is done for both oncologic and functional reasons.

• The mylohyoid muscle forms the floor of the mouth; this muscle and its attachment to the mandible along the mylohyoid line is resected to ensure adequate margins.

• Frozen section is advisable, particularly at the base of the tongue, where it may be difficult to distinguish between tumor and the thick, irregular normal mucosa.

• Total laryngectomy is required when the cancer extends to the pre-epiglottic space and/or epiglottis.

• Optimize function by

  • Preserving as much base of tongue tissue as is possible

  • Ensuring that the reconstructive flap has sufficient bulk to create a convex floor of mouth that permits contact between the flap and the palate during phonation to facilitate articulation, to assist deglutition, and to avoid pooling of secretions

  • Suspending the hyoid bone from the anterior arch of the mandible to facilitate breathing and swallowing

  • Considering using a sensate flap

  • Preserving the superior laryngeal nerves

  • Performing total laryngectomy in patients who are unlikely to tolerate some degree of aspiration

• Bilateral neck dissection (elective or therapeutic) is essential due to the high likelihood of harboring cervical nodal metastases.

Preoperative Period