Glossectomy

Anatomy and Physiology

The tongue is a muscular organ in the mouth that plays a central role in aiding mastication (chewing), deglutition (swallowing), gustation (taste), speech, and articulation. It is a midline structure with mirrored muscle architecture, innervation, and blood supply. The tongue is split into mirrored halves by an avascular midline raphe. Histologically, the mucosa of the tongue is lined with keratinized and nonkeratinized stratified squamous epithelium. It also contains special sensory mucosa for taste perception.

The surface topography of the tongue includes the tip, lateral surface, ventral tongue, dorsal tongue, and tongue base. The tip of the tongue describes the most anterior part of the tongue. The lateral edge of the tongue separates the ventral surface from the dorsal surface of the tongue. The ventral tongue is the undersurface of the tongue, while the dorsal tongue is the superior surface. The base of the tongue is the posterior one-third of the tongue; it includes the tongue tissue posterior to the circumvallate papilla extending to the vallecula (the latter being the region between the base of the tongue and the epiglottis).

The tongue can also be described in thirds. The tip of the tongue is the anterior one-third of the tongue. The posterior one-third of the tongue is the tongue base. The middle third is between the tip and the tongue base. The anterior two-thirds of the tongue is considered part of the oral cavity, while the tongue base at the posterior one-third is considered to be part of the oropharynx.

There are eight paired muscles of the tongue. Muscles of the tongue are classified as intrinsic or extrinsic. The intrinsic muscles do not have insertions or origins external to the tongue; they are confined to the body of the tongue. Their actions shape the tongue but do not change tongue position. They are named for the directions in which they run: superior and inferior longitudinal muscles, transverse muscles, and vertical muscles. Four extrinsic muscles originate outside the tongue and insert into the body of the tongue. These muscles alter tongue position and include the genioglossus, styloglossus, hyoglossus, and palatoglossus muscles.[3]

Motor innervation to the tongue is from the hypoglossal nerve (cranial nerve 12). The nerve originates from the hypoglossal nucleus and exits the skull base through the hypoglossal canal. Once in the neck, it crosses anterior to the internal and external carotid arteries and can be seen deep to the posterior belly of the digastric muscle. It can often be found inferior to the digastric muscle as it proceeds anteriorly, putting it at risk for injury during dissection of neck levels 1B and 2A. The nerve proceeds superomedially deep to the mylohyoid muscle to innervate the intrinsic and extrinsic tongue muscles.

Sensory and special sensory (taste) inputs from the tongue are based on the thirds of the tongue. The sensory function of the anterior two-thirds of the tongue is supplied by the lingual nerve, which comes off the mandibular branch of the trigeminal (V3) nerve. Sensation to the posterior one-third of the tongue is provided by the glossopharyngeal nerve (9). Taste from the anterior two-thirds of the tongue travels along the chorda tympani, which travels early in its course with the lingual nerve (V3) and later in its course with the facial nerve (7). Taste in the posterior one-third of the tongue is from the vagus nerve (10).

Arterial supply to the tongue comes from branches of the external carotid artery, primarily through the lingual artery and the tonsillar branch of the facial artery. Venous drainage is through tributaries to the lingual vein.[4]

Lymphatic drainage from the oral tongue is primarily to levels 1 through 3 of the neck. This includes the submental (level 1a) and submandibular (level 1b) lymph node basins, as well as the upper jugular chain neck lymphatics (levels 2 and 3). Lymphatic drainage from the tongue base is primarily to levels 2 through 4.[5][6] Understanding lymphatics is important in locoregional control of tongue cancers. Neck dissection should always be considered when treating squamous cell carcinoma of the tongue, due to the risk of cervical lymph node metastases, even in the clinically negative (cN0) neck. Clinically N0 necks have been observed to harbor occult metastases at a rate of 20%.[7] Tumor thickness is also associated with cervical lymph node metastases.[8][9][10] Consequently, the nodal disease burden is a predictor of increased mortality, and elective neck dissection has been shown to offer a survival advantage with higher disease-free survival over therapeutic neck dissection.[11][12] Occasionally, lower lymph nodes in levels 3 and 4 can harbor metastases without level 1 or 2 disease and can be thought of as an indication of aggressive management.[13] Neck dissection is therefore strongly recommended as it provides more accurate nodal staging and can also be therapeutic for decreasing tumor burden.

Indications

Glossectomy is commonly performed for the extirpation of malignant and precancerous (or "potentially malignant") oral cavity lesions. Other indications include excisional or incisional biopsy of tongue lesions of undetermined etiology, benign neoplasms of the tongue, obstructive sleep apnea, and macroglossia.

There are multiple approaches to performing a glossectomy. Three approaches to glossectomy discussed in this article include (1) transoral glossectomy, (2) glossectomy via lip-split mandibulotomy, and (3) glossectomy via transcervical pull-through.

Conceptually, transoral glossectomy is the simplest of the three approaches – it is the removal of tongue tissue through the mouth. It requires the least steps, and in the appropriate case, it is the "easiest" approach. It does, however, have limited posterior access and exposure. Because the overwhelming majority of glossectomies are done for cancer, access and exposure are key in achieving a microscopically margin-negative resection. The lip-split mandibulotomy gives the widest exposure, but it is the most time-consuming and carries more risk of complications. In the lip-split mandibulotomy, a sagittal osteotomy is performed to splay open or swing the mandible open to allow inferior displacement of the tongue for a transoral-transcervical exposure of the posterior tongue and pharynx. It requires mandible reconstruction after ablation is completed. Glossectomy via transcervical pull-through is a technique that releases the tongue into the neck through the floor of the mouth by opening the sublingual and submental compartments. It provides inferior displacement of the tongue for improved visualization of the posterior tongue. The exposure is less than the lip-split mandibulotomy approach because of the intact mandible, but since sagittal osteotomy is not performed, mandibular reconstruction is not needed.

Choosing the appropriate approach depends on several factors, including the size, depth, and location of the ablation. The TNM system is used for staging head and neck cancers. TNM is scored based on attributes of the tumor (T), cervical lymph node involvement (N), and distant metastasis (M). The Tumor (T) stage is scored as follows:

• Tis: Carcinoma in situ
• T1: Tumor is less than or equal to 2 cm with a depth of invasion (DOI) less than or equal to 5 mm
• T2: Tumor is less than or equal to 2 cm with DOI greater than 5 mm, or tumor is 2-4 cm with DOI less than or equal to 10 mm
• T3: Tumor is greater than 4 cm, or DOI > 10 mm
• T4: Advanced local disease and invasion into surrounding structures
• T4a: Invasion of nearby structures such as the mandible, maxilla, or skin of the face
• T4b: Very advanced disease, characterized by involvement of the pterygoid plates, skull base, and/or carotid artery encasement

In general, smaller and shallower, Tis, T1, and T2 tumors lend themselves well to transoral resection alone. Larger tumors or tumors with significant depth, such as large T2 to T4a, are better addressed by either transcervical pull-through or lip-split mandibulotomy because of the improved access. T4b disease is unresectable, and surgery is usually contraindicated.

The location of the tumor is equally important in deciding the optimal surgical approach. The more anterior the ablation is, the more amenable it is to transoral resection. As more of the posterior tongue gets involved, exposure becomes a limiting factor. It is important to consider both the size and location of the ablation. For example, a larger tumor (T3) of the tongue tip or anterior half of the tongue may be amenable to resection by a transoral approach only. In contrast, a shallow, 3 cm T2 tumor of the posterior middle-third of the tongue that extends onto the tongue base may be difficult to remove by a transoral approach alone and may be assisted by a transcervical pull-through.

Other surgical factors must be considered for larger tongue resections. As discussed earlier, neck dissection is always considered in glossectomy due to the high rate of cervical lymph node metastases. In cases involving resection of the floor of the mouth, combined with submandibular triangle (IB) nodal dissection, reconstruction may be required to recreate the floor and separate the neck from the oral cavity to prevent fistula. Reconstruction may also be indicated to recreate form and function to a certain degree if a sufficient amount of tongue is resected. Both reconstruction and neck dissection requires transcervical approaches. It may be advantageous to perform an extended procedure if the neck is to be opened. The tumor might extend into the mandible and other compartments in the neck, such as the sublingual space, submental space, or other deep spaces in the neck, and may benefit from the exposure afforded by an extended approach.

Severe trismus is an obstacle to transoral glossectomy. Even with the administration of paralytics, if the jaw cannot be opened, lip-split mandibulotomy or transcervical pull-through may be indicated. Transcervical pull-through requires transoral mucosal cuts that might not be possible in very severe trismus cases. In patients with prior head and neck radiation, lip-split mandibulotomy carries the risk of osteoradionecrosis. If feasible, cervical pull-through may be favored over mandibulotomy due to the theoretical risk of osteoradionecrosis.

The most effective approach is the one that best facilitates a microscopically margin-negative resection. The "easiest" approach may not always be the fastest one; it may be the approach that requires the most additional steps for exposure with the highest risks of complication. The overall impression of weighing the risks and benefits of each approach will help determine the most effective approach.

Contraindications

Other than medical comorbidities that may preclude the patient from undergoing surgery, the principal contraindication is an unresectable disease in the case of malignancies. This includes metastatic disease, extensive or total carotid artery encasement, skull base extension, and invasion into the paraspinal musculature.

Equipment

Equipment used to optimize exposure is key to achieving an oncologic resection.

• Adequate lighting is important in the oral cavity. A headlight is recommended to allow additional light into the oral cavity.
• Mouth gags, bite blocks, and lip retractors are essential to free the hands of the surgeon and assistants.
• Mouth gags can be used in conjunction with a bite block or cheek/lip retractor.
• Traction sutures (e.g., 2.0 or 3.0 silk) or locking fine-tipped forceps can help deliver the tongue out of the mouth for additional exposure.

For mucosal and muscle cuts, electrocautery can provide hemostasis. However, excessive cautery can affect margin interpretation. Cold dissection can be done with bipolar cautery for hemostasis. The CO2 laser offers the advantage over cautery of limiting collateral tissue damage and preserving margin interpretation but offers limited hemostasis by itself.

If mandibulotomy or mandibulectomy is planned, bone cutting instruments will be needed, as well as a mandibular plating set to reconstruct the jaw after the glossectomy is completed.[14]

Personnel

Essential personnel for this procedure includes the primary surgeon, 1 or 2 surgical assistants, a circulating/operating room nurse, a surgical technologist, and an anesthesiologist. Airway management should be discussed with the anesthesiologist prior to starting the procedure.

Preparation

Preparation begins with the preoperative assessment of the tumor and the formulation of an airway plan. This starts with a comprehensive history and physical exam.

A comprehensive clinical history should be obtained at the initial clinical consult. The surgeon should know about prior oncologic treatments, including the status of other cancers, prior surgeries, chemotherapy, and history of head and neck radiation. Other head and neck procedures should be inquired about, including prior neck surgeries/procedures, vascular surgeries, trauma reconstructions, and airway procedures. Conditions that may affect wound healing, including prior head and neck radiation, malnutrition, hypothyroidism, chronic steroid use, autoimmune conditions, and smoking, should be inquired about. If tissue transfer is planned, peripheral vascular disease should be assessed. Airway conditions, including a history of difficult intubations, subglottic stenosis, prior intubations, and history of tracheostomy, should be identified as they will affect the airway plan.

Physical examination should be performed during preoperative consultation to evaluate transoral exposure, as well as visual inspection and palpation of the tumor. Transoral exposure is assessed by asking the patient to open their mouth. Patients with a good opening and a favorable tumor location may need only the transoral approach alone. If the patient has severe trismus, the transoral approach is impossible; these patients will generally need a lip-split mandibulotomy. Edentulous patients are advantageous for glossectomy, as exposure is superior, there is no risk of damaging their teeth, and the flap inset may be performed without the need for circum-dental sutures in patients who may otherwise have poor dentition and periodontal hygiene.

The tumor should be visually inspected to get an accurate assessment of the size, location, depth, and anticipated mucosal margins. The surgeon must predict nearby structures that need to be recruited into the composite specimen for microscopically cancer-negative margins, including the floor of the mouth, contralateral tongue, the base of tongue, pharynx, soft palate, retromolar trigone, maxilla, buccal mucosa, hyoid bone, mandible, and even the larynx. Manually palpating the tongue is equally important to assess the submucosal extent of the tumor and to evaluate for fixation to surrounding structures. Superficial ulcers may give the appearance of a T1 or T2 tumor, but palpation may reveal a T3 tumor with submucosal extension crossing the midline. This may alter the approach from a transoral partial glossectomy to a mandibulotomy with subtotal glossectomy and soft tissue reconstruction.

Palpation of tumors involving the middle one-third of the tongue may necessitate resection of the tongue base, retromolar trigone, or soft palate to obtain adequate margins. Palpation is also important in cases of tumor extending along the floor of the mouth, as it may suggest mandibular invasion requiring segmental mandibulectomy and osseous reconstruction. Patients in severe pain may be difficult to examine in the office. Because in-office assessment may be confounded by patient discomfort, it is important to repeat a rigorous physical examination under anesthesia at the start of the procedure.

Preoperative flexible laryngoscopy and imaging are powerful adjuncts in evaluating tumor extension and the airway. If flexible laryngoscopy and/or imaging demonstrate tumor extension into the pharynx or larynx, the transoral approach alone will be insufficient. Assessment of airway landmarks with flexible laryngoscopy may predict potential intubation difficulties and help formulate a plan to safely secure the airway.

In cases of early-stage oral tongue cancer, there are rarely obstacles to securing the airway. Such patients can be nasally-intubated so as not to have the endotracheal tube obstructing the operative field. With more advanced-stage cancer, the patient may demonstrate findings that portend a difficult airway, such as trismus, tongue fixation, or mass obstruction of the airway. A good total or partial view of laryngeal landmarks may lend itself well to intubation via video-assisted laryngoscopy or awake fiberoptic nasal or oral intubation, depending on the surgical plan. With effacement of laryngeal landmarks and increased laryngeal obstruction, an awake tracheostomy may be indicated in order to secure the airway. Having an airway plan is essential in preparing for a glossectomy procedure.

Patients with severe trismus are difficult to examine preoperatively; as previously discussed; they will need a more sophisticated airway plan. Awake nasal fiberoptic intubation may be recommended if good airway landmarks are present. Awake tracheostomy may be preferred if airway landmarks are effaced or if the surgeon feels it is the safest option.

Once the airway is secured, an examination under anesthesia should be performed. Once again, transoral exposure, visual examination, and palpation of the tumor should be repeated as the planned glossectomy approach may change depending on the findings, including tumor progression in the interval. Patients that were previously difficult to examine in the office due to trismus or severe pain may provide a different surgical assessment when under anesthesia. Direct laryngoscopy at the procedure start may also be performed to assess for tumor extent.

The patient is prepped and draped based on the overall planned surgery. Transoral glossectomy without neck dissection is often considered a "clean-contaminated". If a neck dissection and reconstruction are to be performed, the patient can be prepped and draped once for a "sterile" procedure, whether or not there is anticipated contamination by a connection between the oral cavity and the neck. If a transoral glossectomy is performed with a neck dissection without connecting to the neck, some may perform the glossectomy in a non-sterile fashion first. After the primary tumor is resected with negative margins, the patient may then be prepped and draped for the neck dissection for a sterile procedure. It is the surgeon's preference. Likewise, the administration and choice of antibiotics are at the discretion of the surgeon.

Technique or Treatment

Transoral Glossectomy

Of the techniques discussed, transoral glossectomy is the simplest approach. In the appropriately selected patient, it can provide excellent oncologic clearance with the lowest risk of morbidity of the three approaches discussed. However, it provides the poorest exposure to the posterior tongue. It should be considered in T1/T2 tumors and anterior or shallow tumors. The more anterior the resection, the more amenable it will be to the transoral approach alone. It may be necessary to convert the transoral approach to a lip-split mandibulotomy or cervical pull-through if the exposure is suboptimal for cancer extirpation. 

Self-retaining retractors and mouth gags are used to obtain transoral exposure and free the hands of the surgeon and their assistants. There are a variety of mouth gags that can be used. Commonly used are the Molt, Fergusson, and Jennings mouth gags. A bite block can also be used to keep the mouth open. Mouth gags may be used in conjunction with a cheek or lip retractor to allow more light into the operative field.

Traction on the tongue facilitates the resection by assisting with retraction. This can be accomplished by placing traction sutures or fine-point ratcheting (locking) forceps on the tongue. Handling the tongue with non-locking, toothed forceps is difficult due to the bulk and fluidity of the tongue.

Mucosal and muscle incisions can be made with cautery, laser, or cold instruments. Monopolar cautery provides excellent hemostasis. Though the tongue is highly vascular, excessive cautery can muddle margin analysis of malignant and premalignant margins. In patients where monopolar cautery is not advised, such as patients with cochlear implants or defibrillators, a combination of cold steel and bipolar cautery can be used. The CO2 laser may also be utilized for its advantage in margin interpretation due to its limited collateral tissue damage.

The surgical technique combines visual and haptic feedback. Manually handling the specimen helps gauge tumor depth and improves the likelihood of a negative deep muscle margin. Once exposure and traction are obtained, 1-2 cm mucosal margin incisions are made down to the muscle. Because the more anterior margins are the easiest to gauge, the anterior cuts are generally made first. One may consider making posterior cuts early, if feasible, because blood trickling from the front of the mouth may obscure the posterior cuts.

Placement of a second traction suture on the specimen adds another vector of counter traction. With the specimen in hand, muscular incisions are made to recruit normal tissue onto the deep margin. Judicious hemostasis and adequate margins are key during muscular dissection. Ventral margins may extend onto the floor of the mouth, and contents of the sublingual compartment may need to be recruited into the specimen for a cancer-free deep margin. As the specimen is being excised, there is usually improved mobility of the specimen. Forward traction on both the tongue and specimen may facilitate the posterior mucosal cuts, which should also be made with at least 1 cm margins when dealing with malignancies. The deep tongue muscle dissection can be joined by the posterior mucosal cuts to deliver an en bloc specimen. Mucosal and deep muscle margins are sent for intraoperative margin analysis.

Depending on the amount of tongue removed, the tongue can be closed primarily, left to heal by secondary intention, or reconstructed. 

Glossectomy via Lip-split Mandibulotomy

The lip-split mandibulotomy combines the transoral glossectomy technique with a sagittal mandibular osteotomy. While the transoral glossectomy can be thought of as a "bird's eye" view of the tumor, the mandibulotomy provides a more "head-on" view of the depth of the tumor. It provides excellent access to the sublingual and submental compartments, as well as the suprahyoid tongue musculature. It also allows inferior displacement of the tongue for a wide view of the posterior tongue and pharynx. Though this approach offers the best overall exposure of the tongue, it requires additional steps that increase the risk of complications.

The technique requires transcervical mandibular exposure and a trans-facial lip-split. As neck dissection is usually performed with this procedure, the neck dissection incision can be extended superiorly from the midline to the lip. A mucosal lip incision is made approximately 1 cm anterior to the gingiva to provide a cuff of tissue sufficient for closure. The incision is extended along the mucosal lip in the sagittal plane between the central incisors for a median mandibulotomy (or between the lateral incisor and the canine for a paramedian mandibulotomy). It is extended anteriorly toward the cutaneous lip, through the vermillion border. The labial artery is usually encountered in the process and clipped or cauterized. Though the incision can be extended along the midline through the chin, we favor placing the incision along the semicircular contour of the chin subunit. Muscular cuts are made through the orbicularis oris, mentalis, and the lip depressors, onto the periosteum of the mandible.

Gingival cuts are then made. Management of the central incisors is at the surgeon's discretion. If not extracted, the roots are at risk of exposure or being dislodged from their periodontal ligament during the sagittal osteotomy. A 15 blade is best for making the gingival cuts between the central incisors. It preserves the most mucosa and does not transmit unintended heat damage that could occur with monopolar cautery. It is often the case, especially in radiated tissue, that monopolar cautery use at this step ablates the gingival tissue, leaving a tissue gap, and increases the risk of a salivary fistula.

The flaps over the mandible are then elevated in the subperiosteal plane to expose the bone. Subperiosteal dissection need only provide enough exposure to place a fixation plate across the osteotomy. In cases of prior head and neck radiation, a conservative periosteal elevation is best to reduce the risk of osteonecrosis of the jaw. If exposure beyond the canines is needed, care should be taken to avoid damage to the mental nerve as it exits the mental foramen.

At this point, our preference is to place a reconstruction plate on the inferior border of the mandible while it is in continuity. The plate is contoured, and the drill holes and screws are placed. The plate is then removed, oriented, and stored with the screws until the mandible needs to be fixated.

Sagittal osteotomy is then performed. The mandible is splayed open, and the mylohyoid muscle between the mandibular segments can be appreciated. If the muscle is involved with tumor, it should be excised to a negative margin. Myotomy of the mylohyoid completely releases the mandible segments from one another, further improving exposure. The oncologic advantages of this approach are apparent at this step of the procedure: the ability to appreciate the depth of the tumor and a tremendous transoral/transcervical exposure. The glossectomy can be performed with the ability to not only pull the tongue anteriorly out of the mouth but to also pull the specimen inferiorly into the neck to view the posterior cuts. The margins should be sent for intraoperative analysis. The specimen itself can be reviewed with the pathologist to enhance communication with the surgeon.

Another consideration is that the tumors that extend along the floor of the mouth may be adherent to the mandible. The physical exam may demonstrate fixation to the mandible, and imaging may demonstrate cortical erosion or marrow signal asymmetry. Instead of a midline mandibulotomy, segmental mandibulectomy of the involved bone by transcervical approach is another technique for completing the primary resection. Subplatysmal flaps are elevated beyond the mandible. The marginal mandibular branch of the facial nerve is identified and safely retracted out of the field. The soft tissue over planned osteotomies is ablated down to the cortical bone. Bone cuts are made, and the released bone can be retracted to provide additional exposure and an additional traction vector for combined transoral/transcervical resection of the primary.

Glossectomies warranting mandibulotomy/mandibulectomy will usually require soft tissue and mandibular reconstruction. Soft tissue is reconstructed with either a locoregional flap or free tissue transfer. Resected bone is reconstructed with a free bone graft or vascularized osseous free tissue transfer. Reduction and internal fixation can be made with mandibular plates or lag screws. The mucosal closure should be done in such a way to reduce the risk of a postoperative fistula. The lip-split incision requires closure of the gingiva and the mucosal lip. We generally use chromic or synthetic, absorbable sutures on the mucosa. The muscle layers of the chin and neck are reapproximated. Layered closure of the muscles and skin is performed.

Glossectomy via Transcervical Pull-through

Though mandibulotomy provides excellent exposure, the added steps of the lip-split, osteotomy, and mandibular fixation compound risks of postoperative complications. Head and neck cancer patients with hypothyroidism, diabetes, or previous radiation experience an increased risk of fistula, wound dehiscence, and delayed wound healing. Mandibular osteoradionecrosis is another risk in previously-irradiated head and neck patients.

Glossectomy via transcervical pull-through is an alternative resection technique to transoral glossectomy and the lip-split mandibulotomy. It is a combined transoral/transcervical technique whereby the tongue, floor of the mouth, and the sublingual compartment are released through the submental and submandibular compartments into the neck. Compared to transoral glossectomy alone, this approach provides better exposure for a posterior resection. Transoral glossectomy can be converted to a pull-through without adding a significant length of time to the procedure. The exposure is not as wide as the lip-split mandibulotomy. However, it does not require a mandibular osteotomy and thus avoids the added procedure time for mandibular reconstruction and its associated complications. Flap inset requires thoughtful and disciplined closure to reduce the risk of a postoperative fistula.

The transcervical and transoral portions of the procedure can proceed in any order. There is often a need to proceed back and forth between both approaches. The transcervical approach is provided by the neck dissection. Subplatysmal flaps are elevated. After cervical lymph node dissection of the submandibular triangle is completed, the muscular floor of the neck is assessed for tumor extension or need for extending the procedure into a lip-split mandibulotomy. Assuming that the disease is limited to the tongue, the procedure can be completed as described.

Anterior transoral glossectomy is performed, as much as can be done oncologically before the pull-through is required to facilitate the posterior resection. Mucosal cuts are made on the anterior tongue along the dorsal and ventral surfaces. The procedure requires the release of the floor of the mouth, so mucosal cuts are extended along the floor of the mouth. For tumors that involve the floor of the mouth, margins may extend to the gingivoalveolar mucosa. If that is the case, the lingual mucosa of the alveolus can be incised, and the entire periosteum elevated off of the lingual cortex of the mandible to encompass the entire floor of the mouth between the tongue tumor and the mandible. Reconstruction may be assisted by tooth extraction, alveoloplasty, circum-dental inset sutures, or inset to the gingivobuccal mucosa. Placement of a traction suture on the specimen facilitates the pull-through. Once the tumor specimen is separated from the tongue remnant anteriorly and the anterior floor of mouth cuts are made, attention is switched to the transcervical approach.

The mylohyoid and anterior digastric muscles are released from the mandible. Depending on the tumor extent, these muscles can be either transected or resected. If these muscles are involved with tumor, they should be removed and either included in the composite resection (preferred) or sent as a separate margin. The mylohyoid can be released at the mylohyoid line, at its mid-portion, or in the midline. The sublingual compartment is entered, then joined to the floor of mouth cuts, and may include excision of the sublingual gland. The traction suture on the specimen is pulled into the neck, which provides a view of the posterior resection. The specimen is then removed. Margin analysis is performed. If the margins are negative, reconstruction and closure can be completed.

Soft tissue reconstruction of the defect is generally needed if the surgeon has to employ this approach. A combined transcervical/transoral inset method is generally recommended to facilitate wound closure.

Complications

The risks for glossectomy include those pertinent to most surgical head and neck procedures, including pain, bleeding, infection, sequelae of healing, damage to nearby structures, and the need for possible future procedures. Risks of general anesthesia, including cardiopulmonary events, stroke, and death, though remote, must also be considered and discussed with the patient.

Discussion about procedure-specific risks to speech and swallow function is essential in counseling patients. Dysarthria and difficulties with speech or swallowing to varying degrees are almost guaranteed with every glossectomy. The long-term functional outcomes may also vary.[15] Dysarthria and dysphagia are secondary to the loss of intrinsic and extrinsic muscles that shape and position the tongue. Even with shallow partial glossectomy, patients may experience some degree of dysarthria secondary to post-operative changes to their tongue. Flaps used to reconstruct the tongue do not have volitional movement, and so post-operative tongue function is influenced by residual tongue musculature and bulk.[16] Rehabilitation and speech therapy may play a role in optimizing post-glossectomy functional outcomes.[17]

Changes in speech and swallowing may also be secondary to the sequelae of healing. In cases of primary closure, tongue tethering can occur that limits the freedom of movement. Even in cases of secondary intention, tongue tethering can occur from unanticipated annealing of open surfaces to one another.

An altered sensation of the tongue is another inevitable complication. Patients may experience neuropathic or phantom sensations from the soft tissue resection. Sensory changes can also be secondary to lingual nerve trauma during glossectomy or neck dissection. In cases where there is more significant tongue resection, sensory changes are more secondary to loss of the sensory input and from the sacrifice of the lingual nerve. In reconstructive cases with regional flaps or free tissue transfer, the reconstructive substrate is commonly non-sensate, and if the tissue used contains muscle, the muscle cannot be used in any meaningful way to restore motor function. Some institutions perform re-innervated free flaps reconstructions, which provide sensation, but no taste.[18] In cases where the tongue base is resected and reconstructed, the altered sensation combined with the loss of functional tongue muscle can result in aspiration, making the patient dependent on tube feeds.

Patients commonly ask about altered taste. It is a myth that the tongue has specific topography concerning taste. All five taste senses are represented throughout the tongue. Higher acuity taste is facilitated by olfaction via retrograde airflow to the nasal cavity, which should be unaffected by glossectomy.

Salivary fistula is another complication. It occurs when the oral cavity is continuous with the deep neck space. It tends to occur between the floor of the mouth and the submandibular triangle. The loss of the submandibular gland and the vascularized fascia creates a direct communication between the oral cavity and the neck through the floor of the mouth. It can also happen at the site of the sagittal-split osteotomy. In the setting of primary surgery, these wounds tend to heal or can be assisted with some local tissue rearrangement. However, salvage surgery after radiation is prevalent and leaves the operative bed with altered vascularity and impaired healing.[19] Vascularized tissue transfers have become the standard and greatly decrease the risk of fistula, even in the setting of prior radiation.

Another risk with surgery is positive margins and recurrences. Positive margins can make wound closure impossible as the reconstruction might not heal to cancer on the inset margins. The risk of salivary fistula and chronic, non-healing wounds is almost certain in that scenario. Persistent cancer should always be on the differential in a chronic, non-healing wound.

For patients undergoing lip-split mandibulotomy, there are increased risks specific to the osteotomy, including osteoradionecrosis of the mandible, malocclusion, and hardware complications. Osteoradionecrosis is a radiation injury resulting in devitalized bone. If the patient develops osteoradionecrosis, they may require secondary resection and reconstruction.

Even if surgery results in a microscopically-negative margin resection and the wound heals, surveillance could still be complicated. In cases of transoral glossectomy without reconstruction, scar tissue from primary and secondary closure may make it difficult to survey for local recurrences, which may result in future procedures coupled with anxiety for the patient and uncertainty for the oncologists surveilling the patient. In cases with trismus from prior radiation where surgery worsens their trismus, surveillance will be difficult. In such cases, the clinical impression may rely on the sum of imaging, fiberoptic endoscopy, and clinical history.

Clinical Significance

Surgery is the recommended primary treatment for oral tongue cancer. If there are no contraindications to surgery, the NCCN guidelines favor surgery over radiation for oral cavity cancers. Understanding the limitations and advantages of the various approaches to glossectomy can help facilitate resection and allow appropriate counseling of patients on the expected perioperative and postoperative course.

Enhancing Healthcare Team Outcomes

Glossectomy is most commonly performed for the treatment of malignant and pre-malignant tongue lesions. Malignant lesions of the tongue, like other parts of the head and neck, usually require multimodality treatment that utilizes the expertise of a range of professionals, including otolaryngologists, medical oncologists, radiation oncologists, radiologists, surgical pathologists, oral surgeons, speech-language pathologists, dieticians, nurses, and pharmacists.[20] As such, all facets of the procedure, including patient selection, preoperative evaluation, type of glossectomy and surgical approach, postoperative care, and functional rehabilitation, must be performed in a multidisciplinary fashion to optimize treatment (level 3), individualized patient outcomes (level 3), and team efficiency.[21][22][23][24][25] [Levels 3 and 5]

Preoperatively, a comprehensive clinical evaluation of the patient proposed for glossectomy must be performed by the otolaryngologist, as previously described, facilitated with imaging and fiberoptic examinations as necessary. Appropriate consultation referrals in anticipation of adjuvant therapy that may be required after the procedure should be made preoperatively to prevent subsequent delays in treatment. Ideally, the patient is evaluated as part of a multi-specialty tumor board. Preoperative evaluation by internal medicine, cardiology, pulmonology, and/or anesthesia must be performed to allow identification and optimization of comorbidities that may significantly impact surgical safety and outcome.

During the glossectomy procedure, adequate and efficient communication between the surgeon, anesthesiologist, pathologist, and nursing is critical for ensuring a successful surgical outcome, including a margin-negative resection with adequate reconstruction as indicated so as to improve survival prognosis and transition to the next phase of care.

Postoperatively, the management of the glossectomy patient will also require a variety of expertise. Pain control will be optimized with the help of pharmacists. Monitoring of the wound and reconstructive flaps will be performed by the surgical team, including specialist nurses conversant with monitoring for wound infections, reconstructive tissue viability, and other common postoperative complications. As most patients will require dietary modifications after glossectomy, dietitians will be necessary to provide appropriate oral or enteral feeding recommendations based on evaluations from the speech-language pathologists. Speech and swallowing rehabilitation through the help of speech-language pathologists will also be required to optimize patients' quality of life and early re-integration into their pre-existing lifestyle.   

Thus, the need for an interprofessional approach to the preoperative, operative, and postoperative management of glossectomy patients cannot be over-emphasized. It is important that professionals involved in the care of glossectomy patients be aware of the collective roles they play in the management of these patients and the need to strategically be on par with each other to improve patient outcomes.