CC-BY-NC 3.0

TOTAL GLOSSECTOMY FOR TONGUE CANCER

Johan Fagan

Total glossectomy has significant morbidi- ty in terms of intelligible speech, mastica- tion, swallowing, and in some cases, aspira- tion. Consequently many centers treat ad- vanced tongue cancer with chemo- radiation therapy and reserve surgery for treatment failures. Total glossectomy is however a very good primary treatment for carefully selected patients, especially in centers that do not offer chemoradiation. Key surgical decisions relate to whether the patient will cope with a measure of aspira- tion, and whether laryngectomy is re- Figure 1: Extrinsic tongue muscles (palatoglossus quired. not shown)

Surgical Anatomy

The tongue merges anteriorly and laterally Genioglossus with the floor of mouth (FOM), a horse- Vallecula shoe-shaped area that is confined periph- Geniohyoid Mylohyoid erally by the inner aspect (lingual surface) Hyoid of the mandible. Posterolaterally the tonsil- lolingual sulcus separates the tongue from Midline sagittal view of tongue the tonsil fossa. Posteriorly the vallecula Figure 2: separates the base of tongue from the lin- gual surface of the epiglottis.

The tongue comprises eight muscles. Four extrinsic muscles (genioglossus, hyoglos- sus, styloglossus, palatoglossus) control the position of the tongue and are attached to bone (Figures 1, 2); four intrinsic muscles modulate the shape of the tongue, and are not attached to bone. Below the tongue are the geniohyoid and the mylohoid muscles; Figure 3: Geniohyoid and mylohyoid the mylohyoid muscle serves as the dia- phragm of the mouth and separates the Vasculature tongue and FOM from the submental and submandibular triangles of the neck (Fig- The tongue is a very vascular organ. The ures 1, 2, 3). arterial supply is derived from the paired http://openbooks.uct.ac.za/ENTatlas 36-1 Open Access Atlas of Otolaryngology, Head & Neck Operative Surgery lingual arteries and their branches (ranine either side of the genioglossus, and is ac- artery, dorsalis linguae, and sublingual companied by the lingual nerve. Two or arteries) (Figures 4, 5); and the mylohyoid three small dorsales linguæ arteries arise artery and the submental branch of the beneath the hyoglossus and ascend to the facial artery. Additional blood supply to posterior part of the dorsum of the tongue the tongue emanates from the tonsillar and also supply the mucous membrane of branch of the facial artery and the ascend- the posterior FOM, and oropharynx (Fig- ing pharyngeal artery. ure 4). The sublingual artery branches from the lingual artery at the anterior edge of the hyoglossus and runs forward be- tween the genioglossus and mylohyoid and supplies the sublingual salivary gland and mucous membrane of the FOM and gingi- va (Figure 5). A branch of the sublingual artery pierces the mylohyoid muscle and anastomoses with the submental branch of the facial artery in Level 1b of the neck. The submental branch of the facial artery Figure 4: XIIn accompanied by ranine veins courses along the inferior, inner margin of the mandible (Figures 6).

Tonsillar artery

Submental artery

Mylohyoid muscle

Mylohyoid artery

Ranine artery Facial artery

Sublingual artery Figure 6: Facial artery emerges from behind poste- rior belly of digastric (removed), and gives rise to a Lingual artery few branches including submental artery Figure 5: Lingual artery Dorsalis linguae artery The mylohyoid artery and vein are en- The lingual artery originates from the ex- countered when the surgeon elevates the ternal carotid between the superior thyroid submandibular gland from the lateral sur- and facial arteries and courses obliquely face of the mylohyoid (Figure 7). It branch- forwards and medial to the greater cornu es off the inferior alveolar artery just before of the hyoid (Figures 4, 5). It then loops it enters the mandibular foramen, crosses downward and anteriorly and passes medi- the mylohyoid, and disappears anteriorly al to hypoglossal nerve (XIIn) and the sty- behind the digastric. It has connections lohyoid muscle. It then courses directly with the submental artery and via a defect anteriorly and deep to the hyoglossus and in the mylohyoid with the sublingual artery finally ascends submucosally on the under- in the FOM. surface of the tongue as far as its tip as the ranine artery (profunda linguae); it lies to http://openbooks.uct.ac.za/ENTatlas 36-2 Johan Fagan

Lingual nerve

Sublingual gland

Submandibular duct

Submandibular gland

Mylohyoid muscle

Geniohyoid muscle

Figure 8 Superior view of FOM, sub-mandibular Figure 7: Mylohyoid artery is a branch of the inferi- gland and duct, lingual nerve and mylohyoid and or alveolar artery geniohyoid muscles:

Venous drainage is via lingual and ranine veins. The lingual veins originate on the Lingual nerve dorsum, sides, and undersurface of the Submandibular duct tongue and accompany the lingual artery Sublingual gland and joins the internal jugular vein. The ra- Submandibular gland nine veins originate below the tip of the Mylohyoid muscle tongue and are visible on its ventral sur- Figure 9: Intraoral view of left sublingual gland face; they accompany the XIIn as venae with ducts of Rivinus, submandibular gland and comitantes and either join the lingual vein duct, lingual nerve and mylohyoid muscles or pass lateral to hyoglossus to join the common facial vein (Figure 4). The mandible borders the FOM, and may be involved by tumour and may have to be Structures surrounding the tongue divided for access (mandibulotomy) or re- sected (alveolectomy / marginal man- The following structures are located be- dibulectomy / segmental mandibulectomy tween the mucosa and the mylohyoid mus- / hemimandibulectomy). Important surgi- cle: paired geniohyoid muscles in the mid- cal features are the position of the mental line (Figure 3); sublingual salivary glands foramina through which the mental nerves (Figure 8, 9), submandibular ducts (Fig- exit to innervate the lower lip; the mylohy- ures 8, 9), oral component of submandibu- oid line to which the mylohyoid muscle lar salivary glands (Figures 8, 9), and the attaches, the attachment of the genioglos- lingual and XIIns. The paired sublingual sus, and when planning a marginal man- salivary glands are located beneath the dibulectomy, the height of the body of the mucosa of the anterior floor of mouth, an- mandible and the depth of the dental roots terior to the submandibular ducts and (Figures 10a, b). In older, edentulous pa- above the mylohyoid and geniohyoid mus- tients the mental foramen and inferior al- cles. The submandibular duct is located veolar nerve may be very close to the supe- immediately deep to the mucosa of the an- rior surface of a resorbed mandible. A terior and lateral FOM, and opens into the marginal mandibulectomy may also not be oral cavity to either side of the frenulum possible in such a resorbed mandible due (Figures 8, 9). to the lack of residual bone.

http://openbooks.uct.ac.za/ENTatlas 36-3 Open Access Atlas of Otolaryngology, Head & Neck Operative Surgery

Preoperative evaluation

1. Are there synchronous primaries, or cervical and distant metastases? CXR or CT chest, panendoscopy, CT-PET 2. Is the tumour resectable? It may be dif- ficult to assess the extent of the primary due to pain, tenderness or trismus; if in Figure 10a: Attachments of muscles to outer aspect of doubt, a patient requires imaging such mandible and location of mental foramen as CT/MRI, or examination under an- aesthesia. 3. Can the patient tolerate aspiration? Physical fitness, pulmonary reserve, and cognitive function should be con- sidered when selecting patients for total glossectomy especially if to be followed by chemoradiation as a measure of as- piration is inevitable. 4. Is total laryngectomy required? Laryn- gectomy is indicated in patients who are unlikely to tolerate a degree of aspi- ration, and when tumour extends to Figure 10b: Attachments of mylohyoid, geniohyoid, the preepiglottic space and/or epiglottis genioglossus and digastric muscles to inner aspect of mandible (Figure 11).

Surgical Objectives

• Adequate resection margins • Minimise aspiration o Preserve some base of tongue (BOT) tissue if possible o Suspend hyoid from mandible o Total laryngectomy for selected cases • Avoid pooling of secretions and food in the oral cavity • Avoid a permanent PEG tube • Adequate speech and articulation Figure 11: 2nd tongue cancer involving vallecula • and epiglottis and requiring total glossectomy with Control regional metastases: The au- laryngectomy thor advocates bilateral elective neck dissection (END) levels I-IV for ad- vanced tongue carcinoma http://openbooks.uct.ac.za/ENTatlas 36-4 Johan Fagan

Base of tongue ment of medullary bone. If only the

Epiglottis periosteum is involved then a marginal

Vallecula mandibulectomy (removal of cortical

Hyoepiglottic ligament bone) will suffice. Should marginal

Hyoid bone mandibulectomy be considered, then

Preepiglottic space the vertical height of the mandible

Thyrohyoid membrane should be assessed clinically or by

Thyroid cartilage panorex so as to predict whether a free bony composite flap would be required

Figure 12: Relationships of hyoid, epiglottis, vallec- to bolster the remaining mandible. ula, and preepiglottic space Once the cortex is invaded, then either marginal or segmental mandibulecto- Preepiglottic space involvement is di- my is required. Once the medulla is in- agnosed radiologically on CT or MRI vaded, then segmental or hemiman- (sagittal views); or intraoperatively by dibulectomy is done that includes at palpating for thickening of the preepi- least a 2cm length of mandible on ei- glottic space between a finger placed in ther side of the tumour. the vallecula and a finger placed on the 7. Is tracheostomy required? Patients skin of the neck just below the hyoid routinely require a temporary trache- bone (Figure 12). If in doubt, consent ostomy for possible airway compro- the patient for possible total laryngec- mise related to bleeding, soft tissue tomy based on intraoperative surgical swelling, a bulky flap and loss of ante- and frozen section findings. rior laryngeal suspension following di- vision of the mylohyoid, geniohyoid 5. Is there evidence of perineural inva- and digastric muscles. sion (PNI) of major nerves? Examine 8. Type of reconstruction? It is essential the patient for neurological deficits of to have a bulky flap to create a convex the XIIn, mental, inferior alveolar and floor of mouth so as to avoid pooling of lingual nerves. Widening of the inferior secretions and to facilitate articulation. alveolar canal on mandibular or- 9. Status of dentition? Carious teeth thopantomography (panorex) may be should be removed at the time of sur- seen with involvement of the inferior gery to prevent osteoradionecrosis. alveolar nerve. MRI may demonstrate PNI. Should there be evidence of PNI Anaesthesia then the affected nerve is dissected proximally until a clear tumour margin The surgeon should always stand by during is obtained on frozen section. induction of anaesthesia as bulky tumours 6. Mandible: Tumour may extend across may preclude elevation of the tongue to the FOM to involve the periosteum, in- visualise the larynx and it may be difficult vade the inner cortex, or involve me- or impossible to intubate the patient. dullary bone. Panorex shows gross in- Should the anaesthetist be unable to intu- volvement of bone. Invasion of cortical bate the larynx, the surgeon may be able to bone is better assessed with CT scan; intubate through a laryngoscope, or do an MRI is superior for assessing involve- emergency tracheostomy or cricothy- http://openbooks.uct.ac.za/ENTatlas 36-5 Open Access Atlas of Otolaryngology, Head & Neck Operative Surgery roidotomy. Nasal intubation facilitates re- Cervical dissection section of tongue tumours, and may be fol- lowed by tracheostomy during the course Incise the periosteum along the inferior of the operation. The author employs na- margin of the mandible from angle-to- sogastric as opposed to PEG feeding. Peri- angle and divide the anterior bellies of di- operative antibiotics are prescribed for gastric and the mylohyoid with electrocau- 24hrs. tery (Figure 14).

Intraoperative evaluation

Panendoscopy is done to exclude synchro- nous tumours of the upper aerodigestive tract. Reassess the extent of the primary cancer, especially for posterior and lateral extension, as well as reassess the neck for cervical metastases.

Total glossectomy

Complete the bilateral neck dissections before resecting the primary tumour (Fig- Figure 14: Incise periosteum along lower margin of ure 13). mandible from angle to angle (yellow line), and di- vide anterior bellies of digastric (green line)

Mandibular Then strip the soft tissues off the medial periosteum aspect of mandible in a subperiosteal

Anterior belly plane. If tumour does not extend to the digastric lateral FOM, then strip beyond the mylo- Mylohyoid hyoid line to free mylohyoid from bone Hypoglossal n (Figure 15). Free the geniohyoid muscle Hyoid from the inferior mental spine (Figures 15, 16)

Transoral dissection

Figure 13: Exposure following bilateral SND First doing a marginal mandibulectomy when tumour abuts the mandible greatly Good surgical access is essential in order to facilitates the tongue resection. Incise the attain adequate resection margins, to con- gingival mucosa along the alveolar ridge trol bleeding, and for reconstruction. The (Figure 17). Strip the soft tissue off the author’s preference of a combination of mandible with monopolar cautery; limit transcervical and transoral access will be exposure of the anterior surface of the described. Others prefer a midline lipspit mandible in order to maintain its blood incision with mandibulotomy (See chapter: supply (Figure 18). Take care (if possible) Partial glossectomy). http://openbooks.uct.ac.za/ENTatlas 36-6 Johan Fagan not to injure the mental nerve where it ex- its the mental foramen.

Figure 15: Mylohyoid line and attachments of gen- iohyoid and genioglossus to inferior and superior mental spines; blue line indicates marginal man- dibulectomy Figure 18: Cut along dotted line with a power saw.

Perform a marginal mandibulectomy along the superior aspect of the horizontal ramus of the mandible as indicated in Figure 18. Angle the cut so as to include the mylohy- oid line; this is especially important if tu- mour extends to the lateral FOM and abuts bone (Figures 15, 19). Not only does the marginal mandibulectomy have oncologi- cal relevance in terms of resection margins, Divide geniohyoid at its attachment to Figure 16: but it avoids the sump effect of having a the inferior spine of the mandible concavity along the medial border of the mandible as will become apparent later in the chapter.

Glossectomy

The marginal mandibulectomy, FOM and tongue are delivered into the neck (Figure 19). This permits the surgeon to resect the tongue with excellent exposure of the can- cer and the vallecula (Figure 20).

Figure 17: Incise along gingival margin Preserve as much BOT mucosa as possible to facilitate swallowing. The specimen is examined for adequacy of resection mar- gins, and sent for frozen section if available (Figure 21). http://openbooks.uct.ac.za/ENTatlas 36-7 Open Access Atlas of Otolaryngology, Head & Neck Operative Surgery

Figure 21: Resected cancer with marginal man- dibulectomy

Figure 19: Marginal mandibulectomy, FOM and tongue dropped into neck

Figure 22: Small amount of residual base of tongue

Reconstruction

The key functional elements of reconstruc- tion are that the flap have enough bulk to create a convex floor of mouth so as to Transcervical resection under excellent Figure 20: avoid pooling of secretions and to facilitate vision articulation, and that the hyoid be sus- An assessment is then made about the need pended from the mandibular arch to facili- for total laryngectomy based on the loca- tate breathing and swallowing. tion of the posterior margin; should the epiglottis and preepiglottic fat be unin- A range of flaps will provide adequate tis- volved and the patient is mentally and sue volume i.e. pectoralis major (See chap- physically fit enough to tolerate some aspi- ter: Pectoralis major flap), latissimus dorsi, ration, then one can proceed to recon- anterolateral free thigh or rectus abdomi- structing the defect (Figure 22). nis free flaps (Figure 23). Radial free fore- arm flaps should not be used as they have inadequate bulk and result in a concave floor of mouth and a sump that interferes with deglutition and causes pooling and http://openbooks.uct.ac.za/ENTatlas 36-8 Johan Fagan spillage of saliva and food. Mandibulecto- my may necessitate free fibula flap recon- struction.

Figure 25: Long-term result of pectoralis major flap used to create a convex FOM Figure 23: Large anterolateral thigh flap

The flap should be large enough so that it bulges up to the hard palate with the knowledge that it will flatten out with time (Figures 23, 24, 25). The edges of the flap are sutured to the gingivobuccal and gin- givolabial mucosae with continuous vicryl sutures (Figure 24). The aesthetic benefit of preserving the lower teeth needs to be weighed up against the fact that the teeth Figure 26: Reconstructed tongue with preserved have limited functional value in the ab- dentition sence of a functioning tongue and that the lateral FOM will serve as a sump for saliva Laryngeal suspension is required to facili- tate swallowing and to avoid obstructive and food (Figure 26). sleep apnoea as all attachments of the lar- ynx to the mandible have been severed (an- terior bellies of digastric, mylohyoid, gen- iohyoids and genioglossus). This is achieved by suspending the hyoid bone from the anterior arch of the mandible with thick non-absorbable sutures (Figure 27).

Figure 24: Large flap creates convex FOM

http://openbooks.uct.ac.za/ENTatlas 36-9 Open Access Atlas of Otolaryngology, Head & Neck Operative Surgery

Closure Total glossectomy with total laryngecto- my The neck is closed over suction drains. A tracheostomy is done. The operation is done in exactly the same manner other than the laryngectomy which is added to the procedure.

Author and Editor

Johan Fagan MBChB, FCORL, MMed Professor and Chairman Division of Otolaryngology University of Cape Town Cape Town South Africa Figure 27: Laryngeal suspension [email protected]

Postoperative management

Once the patient is thought to have an ad- equate airway, the tracheostomy is initially corked overnight before being removed. The speech and swallowing therapist sub- sequently assists the patient with swallow- ing. Because of the absence of oral transport, this involves taking thickened liquids and pureed food initially being placed in the back of the mouth with a sy- ringe or spoon until the patient learns to throw the head back and use gravity to as- sist with the oral transport phase of swal- lowing.

http://openbooks.uct.ac.za/ENTatlas 36-10