Recurrent Laryngeal Nerve Lesion

Recurrent laryngeal nerve (RLN) lesion, either temporary or permanent, unilateral or bilateral, during TRA or CTRA is reported in a range from 0 to 12%.2,4,5,8,9,13–15 Identification of the RLN during this type of procedure is not systematically performed, except when the airway resection follows thyroidectomy performed for thyroid cancer infiltrating the cricotracheal junction, in which case the RLNs have usually already been identified during thyroidectomy. To prevent any RLN lesion during TRA and CTRA performed for benign stenoses, surgical dissection of the trachea and cricoid should always be conducted in a subperichondral plane, leaving laterally any scar tissue in which the nerves could be embedded. Particular attention must be paid when isolating the stenotic part of the airway, where the tracheal deformation can cause alteration to the normal course of the RLN. At the level of the cricoid, surgical dissection is performed safely if maintained in between the cricothyroid joints and inside the posterior aspect of the perichondrium of the cricoid plate.

The use of gauze soaked in warm water and epinephrine may be of help in minimizing the use of bipolar forceps for small vessels, especially in heavily inflamed surgical fields. Ligatures and clips are also useful. Monopolar cautery should be avoided whenever in close proximity to the RLNs, whereas cautious bipolar use should be associated with simultaneous saline irrigation of the surgical field to reduce the risk of thermal damage to the nerves.

Extubation, either in the operating room immediately after surgery or during the following day(s) in the intensive care unit, is performed under endoscopic control by a flexible fiberscope with a suction channel through the nose. If bilateral RLN palsy is diagnosed, immediate reintubation and tracheotomy, performed at least two or three tracheal rings below the anastomotic line, are required. Subsequently, in case of failure to recover the function of at least one RLN, an elective posterior cordotomy by CO₂ laser can be considered as an option. In the case of postoperative unilateral RLN palsy, serious airway problems are usually not observed, unless this lesion is associated with an anterior arytenoid subluxation or laryngeal edema (e.g., in the case of extensive neck dissection for neoplastic disease involving the cricotracheal junction). Aerosol of racemic epinephrine, elevation of the head of the bed, absolute voice rest, and a judicious use of intravenous corticosteroids usually help in reducing laryngeal edema in the first 2 to 3 days after surgery. Speech therapy to optimize the phonatory compensation usually starts not earlier than 1 month after surgery, unless concomitant swallowing problems are observed. In the case of incomplete glottic closure in spite of intense speech therapy, delayed vocal fold augmentation phonosurgical procedures will be proposed to the patient.

An expected sequela of CTRA involving the cricoid arch or cricoid plate is a certain degree of vocal fold detensioning as the result of the removal of part of the cricoid cartilage and cricothyroid muscles. This condition is usually associated with persistent mild dysphonia with limitations in pitch and intensity modulation of the voice ( Fig. 21.4 ).

Postoperative Bleeding

Both TRA and CTRA present a risk of postoperative bleeding similar to other head and neck surgical procedures but the delicate situation of the airway in these patients (usually without postoperative tracheotomy) requires an urgent revision of the surgical field within a few hours to avoid laryngeal edema and respiratory distress. The source of bleeding is usually located at the thyroid gland level where the use of bipolar cautery is reduced as much as possible to avoid the risk of causing thermal damage to the RLNs. Moreover, in the case of TRA or CTRA for neoplastic disease, the surgical field can be extended to the entire thyroid and lateral cervical regions, resulting in the presence of other potential sources of postoperative bleeding.

Compressive dressings at the end of the procedure are generally less effective than after other major head and neck operations, because of the need to avoid airway discomfort and because of the position of the patient, with the head flexed on the thorax by chin to chest sutures. The absence of any protective tracheotomy after TRA and CTRA also means an increased risk of coughing in the postoperative period. The repeated Valsalva maneuvers may be the cause of hypertensive episodes predisposing to postoperative bleeding. The vacuum drainage that is usually inserted in the surgical field may also lose its effectiveness if the anastomosis is not perfectly sealed, especially during coughing.

For all these reasons, medical and nursing monitoring of wound drainage in such patients should be particularly close in the first 24 to 48 hours. An unrecognized postoperative hemorrhage, although minor, can quickly lead to respiratory distress as the result of pharyngolaryngeal edema or oozing of blood from the anterior cervical compartment through the anastomosis into the airway. As soon as the complication is diagnosed, the patient should be reintubated under endoscopic guidance, extending the head as little as possible to avoid anastomotic rupture. The hematoma is then drained through a redocervicotomy approach and hemostasis is performed with scrupulous care not to damage the RLNs. A small tracheotomy, performed at least two or three rings below the anastomotic line, is recommended to prevent any airway compromise from the the laryngopharyngeal edema that is usually associated with further revision maneuvers.

Another event that may lead to important, often fatal, bleeding after TRA or CTRA is the erosion of the innominate trunk by an extremely low anastomosis at the cervicomediastinal junction. Fortunately, this is an extremely rare complication (ranging between 0.3 and 0.7% for postintubation and inflammatory stenoses and between 1.2 and 4.3% for neoplastic ones), in which a dominant role is played by the greater extent of airway resection, removal of paratracheal metastatic lymph nodes, especially when associated with total thyroidectomy, and previous radiotherapy. Other predisposing factors can be a high position in the neck of the innominate trunk, as occurs in young, thin, and female patients, or the low location of the trachea itself, as observed in the elderly. This type of hemorrhage virtually disappeared after the abandonment of the Neville silicone prosthesis, used in the 1960s and 1970s for tracheal reconstruction after resection of more than 5 cm of airway length (with a reported incidence of tracheoesophageal innominate fistula around 57%).12,16,17

The safest and easiest way to prevent such a catastrophic event is to insert soft tissues (e.g., thymus, thyroid, or muscle flaps) between the anastomosis and these large vessels. The appearance of the fistula, resulting in a high risk of rupture of the artery, is usually anticipated by late hemoptysis (around the 6th to 10th postoperative day). Its emergent treatment, whenever feasible, is based on the immediate reopening of the cervicotomy with inspection of the vessel and subsequent vascular repair or ligation.