Practice Essentials
During the 1800s, the mortality rate from thyroid surgery was approximately 40%. Most deaths were caused by infection and hemorrhage. Sterile surgical arenas, general anesthesia, and improved surgical techniques have made death from thyroid surgery extremely rare today.
By developing a thorough understanding of thyroid anatomy and of the ways to prevent each complication, the surgeon can minimize each patient’s risk. Potential major complications of thyroid surgery include bleeding, injury to the recurrent laryngeal nerve (see the first image below), hypoparathyroidism, hypothyroidism, thyrotoxic storm, injury to the superior laryngeal nerve (see the second image below), and infection.
Anatomy of the recurrent laryngeal nerve (RLN).
Superior laryngeal nerve (SLN).
Minor complications
Postoperative surgical site seromas may be followed clinically and allowed to resorb, if small and asymptomatic; large seromas may be aspirated under sterile conditions. Poor scar formation is frequently preventable with proper incision location and surgical technique.
Postoperative bleeding
The incidence of bleeding after thyroid surgery is low (0.3-1%), but an unrecognized or rapidly expanding hematoma can cause airway compromise and asphyxiation. Patients present with neck swelling, neck pain, and/or signs and symptoms of airway obstruction (eg, dyspnea, stridor, hypoxia). Evaluation is as follows:
Physical examination; remove all bandaging and examine the neck for swelling
Imaging studies may be useful in cases of mild neck swelling without airway compromise
Fiberoptic laryngoscopy may be warranted in patients with airway issues without apparent wound hematoma, to assess vocal fold function/LI>
Prevention
Avoid traumatizing the thyroid tissue during the procedure
Provide good intraoperative hemostasis
Avoid the use of neck dressings, as dressing that covers the wound may mask hematoma formation
No definitive evidence suggests that drains prevent hematoma or seroma formation
Injury to the recurrent laryngeal nerve
Recurrent laryngeal nerve (RLN) injury results in true vocal-fold paresis or paralysis. Deliberate intraoperative identification and preservation of the RLN minimizes the risk of injury.
Evaluation
Techniques for assessing vocal fold mobility include indirect and fiberoptic laryngoscopy
Documentation of vocal fold mobility should be a routine part of the preoperative workup
Postoperative visualization should also be performed, as patients may be asymptomatic at first
Laryngeal electromyography (EMG) may be useful to distinguish vocal fold paralysis from injury to the cricoarytenoid joint secondary to intubation, and it may yield prognostic information
Presentation
In unilateral vocal cord paralysis, hoarseness or breathiness may not manifest for days to weeks; other potential sequelae are dysphagia and aspiration
Bilateral vocal-fold paralysis usually manifests immediately after extubation; patients may present with biphasic stridor, respiratory distress, or both
Treatment
In unilateral vocal cord paralysis, corrective procedures may be delayed for at least 6 months to allow time for improvement in a reversible injury, unless the nerve was definitely transected during surgery; surgical treatment options are medialization (most common) and reinnervation
In bilateral vocal cord paralysis, emergency tracheotomy may be required, but if possible, first perform endotracheal intubation; cordotomy and arytenoidectomy, the most commonly performed surgical procedures, enlarge the airway and may permit decannulation of a tracheostomy
The patient must be counseled that his or her voice will likely worsen after surgery
Hypoparathyroidism
Hypoparathyroidism can result from direct trauma to the parathyroid glands, devascularization of the glands, or removal of the glands during surgery. Postoperative hypoparathyroidism, and the resulting hypocalcemia, may be permanent or transient. Hypocalcemia after thyroidectomy is initially asymptomatic in most cases.
Evaluation of parathyroid function is performed in either of the following ways:
Follow ionized calcium (or total calcium and albumin) levels perioperatively
Measure PTH postoperatively; a normal level accurately predicts normocalcemia
Treatment is as follows:
Asymptomatic hypocalcemia in the early postoperative period should not be treated with supplemental calcium
In symptomatic patients, replace calcium with IV calcium gluconate
Typically, patients who begin to have symptoms can be started on oral calcium and vitamin D
In 1-2 months, an attempt to wean the patient off oral calcium may be made
Dependence on calcium supplementation for longer than 6 months usually indicates permanent hypoparathyroidism
Thyrotoxic storm
Thyrotoxic storm is an unusual complication that may result from manipulation of the thyroid gland during surgery in patients with hyperthyroidism. It can develop preoperatively, intraoperatively, or postoperatively. Signs and symptoms of thyrotoxic storm are as follows:
Anesthetized patients: Evidence of increased sympathetic output (eg, tachycardia hyperthermia)
Awake patients: Nausea, tremor, and altered mental status
Cardiac arrhythmias may also occur
Progression to coma in untreated patients
Treatment is as follows:
For thyrotoxic crisis during thyroidectomy, stop the procedure
Administer IV beta-blockers, propylthiouracil, sodium iodine, and steroids
Use cooling blankets and cooled IV fluids to reduce the patient’s body temperature
Carefully monitor oxygenation
Injury to the Superior Laryngeal Nerve
The external branch of the superior laryngeal nerve (SLN) is probably the nerve most commonly injured in thyroid surgery, with an injury rate estimated at 0-25%. Trauma to the nerve results in an inability to lengthen a vocal fold and, thus, inability to create a high-pitched sound; this may be career-threatening for singers or others who rely on their voice for their profession. Speech therapy is the only treatment. Presentation and diagnosis are as follows:
Most patients do not notice any change in their voice
Occasional patients present with mild hoarseness or decreased vocal stamina
On laryngoscopy, posterior glottic rotation toward the paretic side and bowing of the vocal fold on the weak side may be noted; the affected vocal fold may be lower than the normal one
Videostroboscopy demonstrates an asymmetric, mucosal traveling wave
Laryngeal EMG demonstrates cricothyroid muscle denervation
Infection
Currently, postoperative infection occurs in less than 1-2% of all thyroid surgery cases. Sterile surgical technique is the key to prevention; routine use of perioperative antibiotics has not proven to be beneficial.
Presentation
Cellulitis typically presents as erythema, warmth, and tenderness of neck skin around the incision
A superficial abscess produces fluctuance and tenderness
A deep neck abscess may manifest subtly but can produce fever, pain, leukocytosis, and tachycardia
Evaluation
Send purulence expressed from the wound or drained from an abscess for Gram stain and culture
CT imaging is useful when a deep neck abscess is thought to be possible
To exclude esophageal perforation in patients with a deep neck abscess, an esophageal swallow study performed with sodium amidotrizoate and meglumine amidotrizoate solution (Gastrografin) may be useful
Treatment
Treat cellulitis with antibiotics that provide good coverage against gram-positive organisms (eg, staphylococci and streptococci)
Drain abscesses, and direct antibiotic coverage according to culture findings
For deep neck abscesses, begin with broad-spectrum antibiotics (eg, cefuroxime, clindamycin, ampicillin-sulbactam) until definitive culture results are available
Hypothyroidism
Hypothyroidism is an expected sequela of total thyroidectomy. Measurement of TSH levels is the most useful laboratory test for detecting or monitoring of hypothyroidism in these patients.