• Thyroidectomy describes the complete or partial excision of the thyroid gland.
• Indications include
  • Hyperthyroidism due to autoimmune or multinodular thyroid disease
  • Thyroid malignancy
  • Thyroid nodules with growth potential
  • Goiter causing tracheal compromise, swallowing difficulty, or other discomfort
• Exposure. Following a horizontal incision (lower neck, usually in skin crease if present) into the first three layers (skin, subcutaneous fat, and superficial fascia), the upper flap is elevated until it reaches the thyroid cartilage and the lower flap is pulled downward. The deep fascia is incised in a vertical, midline manner and the infrahyoid muscle is laterally retracted.
• Identification of the parathyroid glands, recurrent laryngeal nerve (RLN), and superior laryngeal nerve (SLN) are performed to protect them from injury.
• Devascularization to the thyroid gland involves clamping and ligating the
  • Superior thyroid artery; a branch of the external carotid. Ligation is typically made proximal to the gland to avoid injury to the external laryngeal nerve.
  • Inferior thyroid artery; a branch of the thyrocervical trunk. Ligation is performed distal to the superior and inferior parathyroid arteries to preserve the blood supply to the parathyroid glands.
• The thyroid is dissected off the trachea (pretracheal fascia) to avoid damage prior to removal of the gland.
• Endoscopic removal has been described but is not commonly performed.

• Supine
• Arms tucked to facilitate the surgeon's access to the neck.
• Shoulder rolled to hyperextend the neck and optimized exposure.

• Generally involves a small incision across the anterior neck at the level of the thyroid cartilage.
• Dissection may be complicated in patients with aggressive cancer, prior surgery, or a history of radiation.
• In rare cases, the thyroid gland extends into the mediastinum (retrosternal goiter) and a sternotomy incision is required.

1–3 hours

Minimal

• Unilateral lobectomy is generally an outpatient procedure.
• Total thyroidectomy is generally associated with a short inpatient admission.

• Intraoperative neuromonitoring may be performed in select cases (endotracheal tube with monitoring electrodes [e.g., NIM tube]).
• Ultrasound for anatomic confirmation of lesion location (select cases).

• RLN damage.
  • RLN is a branch of the vagus nerve (CN X) and provides sensation to the trachea and innervation to all the muscles of the larynx (vocal cord adductors and the single abductor posterior cricoarytenoid), except the cricothyroid muscle.
  • Unilateral RLN damage leads to hoarseness.
  • Bilateral partial RLN damage (to the abductor) leads to stridor and respiratory distress (from unopposed adduction by the RLN and the SLN's cricothyroid muscle).
• SLN damage.
  • SLN is a branch of the vagus nerve and provides sensation to the larynx and innervation to the cricothyroid muscle.
  • Unilateral SLN damage has minimal effects.
  • Bilateral SLN damage leads to hoarseness and easy tiring of the voice.
• Hypoparathyroidism. Inadvertent removal of the parathyroid glands can lead to acute hypocalcemia with spasticity/tetany.
  • If removal of parathyroid glands is recognized, they can be surgically reimplanted.
• Hematoma leads to airway compromise.
• Hypothyroidism (iatrogenic).

Rare

History

Patients typically present for surgery after a thyroid mass/nodule is found on incidental exam. The majority of patients are asymptomatic.

Signs/Physical Exam

• Thyroid goiter
• Tachypnea and/or stridor from airway compression
• Hyperparathyroidism is associated with tachycardia, tremors, and perspiration
• Exophthalmos/periorbital edema is associated with Grave's disease.
• Inability to lie flat on exam (air hunger).
• Inability to produce a forceful cough during valsalva.

Labs/Studies

• Thyroid function tests: Thyroid stimulating hormone (TSH), T4 (free + total), T3
• CBC (mild anemia is common)
• Electrolytes (including ionized calcium)
• Flow-volume loops. Evaluate for airway obstruction in the sitting, reclining, and supine positions if anterior mediastinal mass is suspected or present.
• ECG. Assess for normal rhythm, QT interval, and presence of other disease.
• CXR. Evaluate for active infection, tracheal deviation, and extension into mediastinum.
• CT. Further assessment of mediastinal involvement and tracheal impingement.
• Consider preoperative otorhinolaryngology consultation and functional vocal cord evaluation in patients with hoarseness or in high-risk procedures (cancer, reoperation, post-radiation thyroid procedure). This is primarily a surgical issue to facilitate postoperative assessment of nerve injury.

Anxiolytics as appropriate; use with caution if airway compression is suspected.

None

• General endotracheal anesthesia is the most common approach.
  • LMAs can be considered in select patients.
• Local/regional block with sedation can be considered in select patients (not common).
  • Cervical plexus block with local infiltration.
  • Not optimal for monitoring cases or procedures involving large goiters and invasive disease.

• Standard ASA monitors.
• Neuromonitoring (select cases).
• Invasive arterial monitoring in patients with significant risk of thyrotoxicosis.

• In most patients, the thyroid goiter has minimal impingement on the airway and no special measures are required.
• Patients with a significant tracheal impingement should undergo topicalized, awake fiberoptic intubation.
  • Tracheal compromise is suggested by CT findings, an obstructive pattern on flow-volume loops, or the presence of severe dysphagia, hoarseness/stridor, or difficulty lying flat.
  • Consider using a small ETT if tracheal compression is suspected.
• Videolaryngoscopy (GlideScope, etc.) can facilitate placement of the EMG's electrode sensors at the vocal cords.
  • Allows the surgeon and neurophysiologist to confirm placement of the tube and avoid repeated laryngoscopy.
  • Used intraoperatively to reevaluate the position of electrodes if the signal is lost.

• General anesthesia with volatile anesthetics or total IV anesthetic.
• Muscle relaxant is not necessary for surgical exposure. Avoid long-acting relaxant if monitoring the RLN.
• Consider dexamethasone for postoperative nausea and vomiting prophylaxis and modulation of airway edema.

• Carefully consider the need for postoperative intubation. Tracheomalacia, leading to dynamic airway obstruction, can occur in patients with significant preoperative tracheal involvement by the thyroid mass. Acute airway obstruction is a concern in the setting of intraoperative RLN injury.
  • Functional evaluation of vocal cord function can be performed at emergence via fiberoptic assessment. Performed as the ETT is withdrawn at emergence or via an LMA placed prior to emergence.
  • Continuous real-time monitoring for vocal cord movement during surgery with fiberoptic bronchoscopy through an LMA has been proposed.
  • Low-dose remifentanil infusion (0.02–0.05 µg/kg/min) may facilitate tolerance of the ETT and functional vocal assessment, while minimizing coughing.
• Avoid coughing at emergence. Straining against the ETT may promote suture disruption and hematoma formation. Postoperative hematoma formation can cause airway compromise.
  • Resumption of spontaneous ventilation during closure may facilitate prompt extubation on emergence.
  • Suctioning of the airway should be done before extubation and while the patient is "deep" to remove any accumulated blood or secretions that can stimulate coughing.