Thyroidectomy

INTRODUCTION — Over the last century, thyroid surgery has evolved from a dangerous and bloody undertaking to a safe operation with favorable outcomes but few major risks, especially when performed by experienced surgeons [1-6].

Thyroid surgery is performed for a number of benign and malignant conditions, which are discussed in detail elsewhere (see 'Indications' below). In this topic, we discuss various surgical aspects of thyroidectomy, including preoperative evaluation and preparation, operative management, postoperative care, and complications.

INDICATIONS — Thyroidectomy may be performed for a number of benign and malignant conditions, including:

●Thyroid nodules. (See "Diagnostic approach to and treatment of thyroid nodules".)

●Hyperthyroidism. (See "Surgical management of hyperthyroidism", section on 'Role of surgery'.)

●Obstructive or substernal goiter. (See "Treatment of benign obstructive or substernal goiter", section on 'Approach to surgery'.)

●Differentiated (papillary or follicular) thyroid cancer. (See "Differentiated thyroid cancer: Surgical treatment".)

●Medullary thyroid cancer. (See "Medullary thyroid cancer: Surgical treatment and prognosis".)

●Anaplastic thyroid cancer. (See "Anaplastic thyroid cancer", section on 'Our approach to treatment'.)

●Primary thyroid lymphoma – Primary thyroid lymphoma is treated with chemotherapy and/or radiation. The role of surgery is limited to obtaining tissue biopsy.

●Metastases to the thyroid – Metastases to the thyroid gland from extrathyroidal primary cancers are rare and are most commonly from renal cell carcinoma in clinical series and the lung in autopsy series [7-9]. Local control can be achieved with thyroid surgery in patients with isolated metastasis to the thyroid.

PREOPERATIVE EVALUATION AND PREPARATION — With few exceptions, thyroidectomy is elective surgery. Thus, any major medical issues should be addressed before proceeding to the operating room [10]. (See "Evaluation of cardiac risk prior to noncardiac surgery" and "Evaluation of perioperative pulmonary risk".)

All patients undergoing thyroid surgery require preoperative imaging, laboratory testing, and laryngeal examination as discussed below. Patients with hyperparathyroidism and those undergoing reoperations need additional preparation [6].

Thyroid imaging — Diagnostic thyroid ultrasound is performed in all patients with a suspected thyroid nodule, nodular goiter, or thyroid abnormality detected by another imaging modality. In patients undergoing thyroid surgery for malignant conditions, ultrasound examination of the contralateral thyroid lobe as well as the lateral and central compartment cervical lymph nodes should also be performed [6,11]. (See "Overview of the clinical utility of ultrasonography in thyroid disease" and "Diagnostic approach to and treatment of thyroid nodules", section on 'Thyroid ultrasonography'.)

Additional imaging modalities, such as computed tomography (CT), positron emission tomography (PET), or magnetic resonance imaging (MRI), may be offered to patients who are suspected of harboring advanced diseases (eg, invasive primary tumor or multiple/bulky lymph node involvement) [12]. CT and MRI can detect extrathyroidal tumor extension into adjacent structures as well as substernal or retropharyngeal diseases [13]. (See "Differentiated thyroid cancer: Surgical treatment", section on 'Importance of preoperative imaging'.)

Laboratory testing — For all patients undergoing thyroid surgery, a serum thyroid-stimulating hormone (TSH) level can determine whether the patient is euthyroid, hyperthyroid, or hypothyroid. A serum calcium level can help identify patients who have concomitant parathyroid disorders [6]. (See "Laboratory assessment of thyroid function" and "Primary hyperparathyroidism: Diagnosis, differential diagnosis, and evaluation".)

For patients diagnosed with medullary thyroid cancer or highly suspected to have medullary thyroid cancer based on family history, preoperative evaluation should also include measurement of serum calcitonin, carcinoembryonic antigen (CEA), genetic testing for germline RET mutations, and biochemical evaluation for coexisting endocrinopathies, such as hyperparathyroidism or pheochromocytoma [14-16]. Medullary thyroid cancer may be hereditary, as in multiple endocrine neoplasia type 2 (MEN2A or MEN2B) syndrome. The evaluation of patients with medullary thyroid cancer is discussed in detail elsewhere. (See "Medullary thyroid cancer: Clinical manifestations, diagnosis, and staging", section on 'Evaluation'.)

Molecular testing may be performed on the biopsy specimen. This may guide the extent of thyroidectomy. (See "Evaluation and management of thyroid nodules with indeterminate cytology in adults".)

Laryngeal examination — Injury or trauma to the recurrent laryngeal nerve (RLN) during thyroid surgery can result in vocal cord paralysis. Thus, occult RLN paresis and/or vocal cord paralysis diagnosed before the surgery can facilitate operative planning and patient counseling. In preoperative discussion, the surgeon should disclose to the patient the possibility, likelihood, and implications of permanent laryngeal dysfunction [6].

Preoperative assessment of the vocal cord function can be done by listening to the patient's voice, direct or indirect laryngoscopy, videostroboscopy (which provides a magnified, slow-motion view of the vocal cords), or laryngeal ultrasound [17]. (See "Inducible laryngeal obstruction (paradoxical vocal fold motion)", section on 'Laryngoscopy'.)

Although some surgeons advocate routine laryngoscopy in all patients undergoing thyroidectomy because voice change was only observed in one-third of patients with a vocal cord paralysis [18], routine testing has not been shown to be either obligatory or cost effective [12,19]. Published clinical guidelines recommend performing preoperative laryngeal examination selectively in patients determined to be at high risk, including [6,12,20]:

●Patients with preoperative hoarseness or voice changes

●Patients with history of prior neck or mediastinal surgery, both thyroid and nonthyroid

●Patients with extrathyroidal extension of tumor posteriorly

●Patients with bulky lymphadenopathy in the central compartment or jugular chain

Additionally, invasive thyroid cancer is associated with a higher risk of occult RLN paresis/vocal cord paralysis. In one study of 365 patients, preoperative vocal cord paralysis was diagnosed by laryngoscopy in 70 percent of patients with invasive disease but only 0.3 percent of patients with noninvasive disease [21].

Preoperative management of hyperthyroidism — According to several clinical guidelines that cover the diagnosis and management of hyperthyroidism and other causes of thyrotoxicosis, patients undergoing surgery for hyperthyroidism should receive [6,22]:

●Preoperative antithyroid medications and/or beta blockade to avoid thyroid storm.

●Preoperative oral Lugol's solution (potassium iodide, SSKI) to block iodine uptake and the secretion of thyroid hormone [23]. Lugol's solution may also decrease vascularity of the thyroid gland and reduce intraoperative bleeding.

●Preoperative vitamin D and calcium supplementation to reduce the risk of symptomatic hypocalcemia postoperatively [24]. Patients with previous gastric bypass surgery are at an increased risk for developing recalcitrant, symptomatic hypocalcemia after thyroidectomy, the management of which may be difficult [25].

Medical optimization of patients undergoing surgery for hyperthyroidism is further discussed in another topic. (See "Surgical management of hyperthyroidism", section on 'Preoperative preparation'.)

Reoperative thyroid surgery — Reoperative thyroidectomy refers to thyroid surgery performed in patients who have had one or more previous thyroid surgeries or other neck operations such as cervical spine surgery via an anterior approach, parathyroidectomy, tracheostomy, or carotid endarterectomy. Reoperative thyroid surgery is technically challenging due to the presence of adhesions and scar tissues in the operative field, has different indications and strategies, and can be associated with higher rates of complications such as RLN injury and hypoparathyroidism [6,20,26,27].

The risks and benefits should be carefully weighed before reoperative thyroid surgery, especially when options for nonoperative management exist (eg, for benign indications) [20,26,27]. Once the decision is made to operate, the surgeon must carefully review all operative and pathology reports from previous operations to determine the prior extent of disease and the visibility, location, and possible loss of parathyroid glands during the previous operations. In many cases, formal review of pathology slides from the previous surgeries may also be informative.

The timing of performing a completion thyroidectomy after a partial thyroidectomy that reveals thyroid cancer remains controversial but has not been shown to impact complication rates [28]. Many surgeons perform completion thyroidectomy either within five to seven days after the initial thyroid lobectomy before intense inflammation in the operative field has set in or delay the operation for at least six weeks to allow time for the inflammation to subside.

OPERATIVE MANAGEMENT

Surgical prophylaxis

Antibiotics — Thyroid surgery has a very low infection rate because it is a clean procedure performed in a well-vascularized area, and thus antibiotic prophylaxis is generally not required [6,29,30]. In patients at high risk for infection, such as those with immunocompromise or poorly controlled diabetes, preoperative antibiotics such as cefazolin can be administered [31,32]. To be effective, preoperative prophylactic antibiotics should be administered within one hour of incision [33-35]. (See "Antimicrobial prophylaxis for prevention of surgical site infection in adults".)

Antiemetics — Prophylactic antiemetics should be given because postoperative nausea and vomiting occur frequently after thyroidectomy. In one trial, a single 8 mg dose of dexamethasone given preoperatively significantly decreased postoperative nausea and vomiting in patients undergoing thyroidectomy [36]. The prevention and treatment of postoperative nausea and vomiting are reviewed in another topic. (See "Overview of post-anesthetic care for adult patients", section on 'Postoperative nausea and vomiting' and "Postoperative nausea and vomiting".)

Venous thromboembolism prophylaxis — For patients undergoing thyroid surgery under general anesthesia, mechanical methods of thromboprophylaxis, such as sequential compression devices, should be employed. After surgery, patients are encouraged to get out of bed and ambulate as early as possible; most patients are able to do so in the evening after their surgery. (See "Prevention of venous thromboembolic disease in adult nonorthopedic surgical patients".)

Anesthesia — Thyroid surgery can be performed under general or local/regional anesthesia. While the vast majority of thyroidectomies are performed under general endotracheal anesthesia, local or regional anesthesia can be used selectively provided that the anatomy and pathology are favorable, the patient is able to communicate with the operating room staff and does not mind being conscious, and clinician expertise in performing a cervical plexus block is available (figure 1). (See "Anesthesia for patients with thyroid disease and for patients who undergo thyroid or parathyroid surgery", section on 'Choice of anesthetic technique'.)

Patient position and skin preparation — The patient is placed on the operating table in a supine, semi-Fowler, or "beach-chair" position, typically with the neck in extension. A roll can be placed transversely under the scapulae to facilitate exposure of the anterior neck, and care should be taken to avoid neck hyperextension (figure 2).

Although issues of operative access and safety also pertain, excessive neck extension during surgery can result in postoperative pain. As an example, patients reported greater postoperative pain after undergoing thyroidectomy with than without neck extension in a randomized trial [37]. Extensive hyperextension of the neck can also lead to vertigo, headache, and postoperative nausea [38]. Patients with known cervical spine disease should be assessed preoperatively by an orthopedic surgeon or neurosurgeon.

The skin of the anterior neck, from the lower lip/angle of the mandible to the anterior chest, should be prepared. If mediastinal surgery is contemplated, the entire chest should be prepared and included in the operative field.

Incision — A Kocher (or collar) incision is made sharply on the anterior aspect of the midneck. Efforts should be made to place this incision in an existing skin crease if possible. The incision length should be based on the size of the underlying thyroid gland as well as patient body habitus [39]. A longer incision may be needed if the patient is obese, the gland is large, or the neck is foreshortened, as with kyphoscoliosis (figure 3).

Exposure — After the incision, dissection is carried down to the platysma muscle. A layer that is only a few millimeters thick, the platysma muscle is divided along the course of the incision with cautery. Subplatysmal flaps are then elevated to above the level of the thyroid cartilage superiorly, over the sternocleidomastoid muscles laterally, and the level of the sternal notch inferiorly (figure 4).

The raphe between the strap muscles is opened in the midline avascular plane. Any enlarged lymph nodes in the midline prelaryngeal area (Delphian nodes) should be excised because they can portend locally metastatic disease. The strap muscles, which include the sternothyroid and sternohyoid muscles, are routinely preserved. However, if the thyroid tumor is adherent to or frankly invades the strap muscles, any involved portion of the muscles should be resected en bloc with the tumor to maintain a negative margin.

Dissection of the thyroid gland

●Starting with the isthmus, one lobe of the thyroid gland is dissected from medial to lateral across the anterior capsule.

●When the lateral border of that lobe is reached, the middle thyroid vein should be identified and divided. The thyroid lobe is then rolled lateral to medial to display its posterior capsule and the tracheoesophageal groove, taking care not to enter the thyroid capsule (figure 5).

●The superior pole vessels are dissected out and ligated as close as possible to the thyroid capsule (figure 6). All thyroid tissues from the superior pole area are then removed. The external branch of the superior laryngeal nerve crosses the vessels close to the superior pole of the thyroid. Retraction of the superior pole in a lateral and inferior direction during dissection can facilitate visualization of the nerve.

●Dissection then continues down along the lateral aspect of the thyroid lobe. Mobilization of the superior pole may aid in the identification of the recurrent laryngeal nerve (RLN). The RLN should be visually identified in the tracheoesophageal groove and protected through its course. Placement of an oral or nasogastric tube, an esophageal stethoscope, or a temperature probe facilitates identification of the tracheoesophageal groove and the RLN.

●The inferior vascular pedicle, along with any other blood vessels going to and from the thyroid in its vicinity, should be ligated, which allows the thyroid lobe to be rolled up and onto the anterior surface of the trachea (figure 7). A trial of 319 patients undergoing total thyroidectomy reported that dissection along the thyroid capsule with branch ligation of the inferior thyroid arteries resulted in a lower rate of transient hypocalcemia compared with truncal ligation of the inferior thyroid arteries (3.1 versus 22.9 percent) [40].

●The ligament of Berry should be divided as close to the trachea as possible near the insertion of the RLN or its branches into the cricopharyngeus muscle (figure 8). Great care has to be taken with this step because the ligament of Berry is the most common site of injury for the RLN (figure 9).

●The isthmus should then be separated from the anterior aspect of the trachea, and the pyramidal lobe followed as cephalad as possible and resected en bloc with the thyroid (figure 10).

●For a thyroid lobectomy and isthmusectomy, the dissection is then complete. A heavy clamp (eg, Kelly clamp) can be applied across the junction of the isthmus and the contralateral thyroid lobe, the thyroid sharply divided, and the stump oversewn with a hemostatic absorbable suture (figure 11). Alternatively, a harmonic scalpel can be employed to divide the isthmus. The specimen is then oriented and labeled for pathology.

●For a total thyroidectomy, dissection continues onto the contralateral lobe using gentle traction of the mobilized isthmus to help expose that lobe. If any type of central neck dissection or cervical thymectomy is to be performed, it can be done en bloc with the thyroidectomy specimen or separately after the thyroid lobe or gland has been removed.

Closure — Prior to closure, the surgical field is evaluated for hemostasis. The strap muscles are then reapproximated with absorbable interrupted sutures at the midline (figure 12). The platysma muscle is closed, followed by skin closure with sutures or skin glue.

Extent of resection — The extent of initial thyroidectomy for certain thyroid diseases remains controversial. We suggest the following approaches, which are consistent with published clinical guidelines [12]:

●Total thyroidectomy is the procedure of choice for patients with Graves' disease, medullary thyroid cancer, and for those with a high-risk differentiated thyroid cancer. High-risk differentiated thyroid cancer is defined by tumor ≥4 cm or with gross extrathyroidal extension, clinically apparent metastatic lymph nodes or distant metastases, or thyroid cancer in a patient with prior radiation to the head and neck or family history of differentiated thyroid cancer in a first-degree relative [41-43]. (See "Differentiated thyroid cancer: Overview of management" and "Medullary thyroid cancer: Surgical treatment and prognosis" and "Surgical management of hyperthyroidism".)

●Either a total thyroidectomy or a thyroid lobectomy may be performed in patients with a low-risk differentiated thyroid cancer, including those with a differentiated thyroid cancer between 1 and 4 cm without gross evidence of extrathyroidal extension or clinical evidence of central or lateral compartment lymph node metastases [12]. (See "Differentiated thyroid cancer: Surgical treatment".)

●Unifocal differentiated thyroid cancers that are <1 cm (papillary thyroid microcarcinoma) may undergo active surveillance or thyroid lobectomy. Ideal patients for active surveillance include those with solitary tumors ≤1 cm with well-defined margins and no evidence of lymph node metastases, who are older than 60 years, who understand that surgery may be recommended in the future, and who are being managed by an experienced team [44,45]. When surgery is planned, thyroid lobectomy is appropriate for most patients; in patients with a familial thyroid cancer and/or a history of radiation to the face, neck, or chest, total thyroidectomy should be performed. (See "Differentiated thyroid cancer: Surgical treatment" and "Diagnostic approach to and treatment of thyroid nodules", section on 'Malignant (Bethesda VI)'.)

In operative management, the minimum acceptable extent of thyroidectomy for unilateral diseases is a complete ipsilateral lobectomy. Incomplete thyroid resections, such as thyroid "nodulectomy" or partial lobectomy, are no longer performed, because they predispose patients to disease recurrence, scar tissue, and the need for reoperations.

Graves' disease or multinodular nontoxic goiter can best be treated with total thyroidectomy. Less extensive techniques, such as unilateral lobectomy and isthmusectomy (Dunhill operation) or bilateral subtotal thyroidectomy, are not recommended, because they either carry a greater risk of disease recurrence [41-43] or a greater risk of complications (eg, RLN injury or hypoparathyroidism) if a reoperation is required [20,26,27]. (See "Surgical management of hyperthyroidism", section on 'Extent of resection'.)

Lymphadenectomy — The extent of lymphadenectomy required at the time of thyroid surgery is based on the type of thyroid malignancy and its risk of lymph node metastasis [11,12]. (See "Neck dissection for differentiated thyroid cancer".)

●All patients with a medullary, papillary, or follicular thyroid cancer and clinical or radiological evidence of lymphadenopathy should undergo a therapeutic lymphadenectomy of the appropriate compartment(s) at the time of their initial thyroid surgery (figure 13 and figure 14).

●Prophylactic lymphadenectomy should be performed only in the following situations:

•For patients with medullary thyroid cancer, the central compartment (level VI) nodes should be removed prophylactically. (See "Medullary thyroid cancer: Surgical treatment and prognosis", section on 'Surgical approach'.)

•For patients with papillary thyroid cancer, a prophylactic central neck lymphadenectomy can be performed in patients with large (≥4 cm) tumors or extrathyroidal extension. Thyroidectomy can be performed without central lymphadenectomy in patients who have small (<4 cm) tumors without extrathyroidal extension or lymph node involvement. This approach resulted in a local recurrence rate of only 5 percent [46]. A 2022 systematic review and meta-analysis of five randomized trials of clinically node-negative papillary thyroid cancer found no difference in the rates of locoregional recurrence, hypoparathyroidism, recurrent laryngeal nerve injury, and bleeding between total thyroidectomy alone and total thyroidectomy plus prophylactic central neck dissection [47]. (See "Differentiated thyroid cancer: Surgical treatment", section on 'Approach to lymph node dissection'.)

●Since follicular thyroid cancer spreads hematogenously, and oncocytic (formerly known as Hürthle cell) thyroid cancer rarely spreads lymphatically, there is little role for prophylactic cervical lymphadenectomy in either patient population. (See "Differentiated thyroid cancer: Surgical treatment", section on 'Approach to lymph node dissection'.)

Parathyroid glands — Most patients have four parathyroid glands in close association with the thyroid gland. Identification and preservation of the parathyroid glands is essential during thyroidectomy.

Parathyroid preservation — Knowledge of the surgical anatomy is important for the identification of parathyroid glands during thyroid dissection. The superior parathyroid glands are located posterior to the RLN; the inferior parathyroid glands are located anterior to the RLN (figure 15). (See "Surgical anatomy of the parathyroid glands".)

To avoid injuring the parathyroid glands, the thyroid dissection should be carried out as close to the capsule as possible while ensuring extirpation of all visible thyroid tissues. Once identified, parathyroid glands should be preserved in situ on their native vascular pedicles. The inferior thyroid artery supplies 80 percent of the parathyroid glands. Thus, the inferior thyroid artery must be ligated close to the thyroid capsule to avoid encroaching upon the branches supplying the parathyroid glands, which take off more laterally (figure 15).

Parathyroid glands should not be removed during thyroid surgery unless they are grossly invaded by a thyroid malignancy or become severely ischemic during dissection. In the latter case, the parathyroid gland can be autotransplanted into a well-vascularized muscle such as the strap or sternocleidomastoid muscles [48]. (See 'Parathyroid autotransplantation' below.)

Newer technology such as indocyanine green fluorescence or near-infrared autofluorescence can be used to identify parathyroid glands and assess parathyroid viability to guide autotransplantation. Advances in the field of near-infrared autofluorescence technology for the identification and localization of parathyroid glands led to US Food and Drug Administration approval of two near-infrared fluorescence detection devices. While additional validation studies are required, better identification and localization of parathyroid glands may lead to a decrease in postoperative hypoparathyroidism [49-51]. (See 'Hypocalcemia/hypoparathyroidism' below.)

Parathyroid enlargement — One or more enlarged parathyroid glands can be incidentally found during thyroid surgery in normocalcemic patients. Management depends upon the number of glands that are enlarged:

●Resection of a single incidentally encountered enlarged parathyroid gland is usually appropriate [52]. An intraoperative parathyroid hormone (PTH) level should be obtained, if possible, to document occult hyperparathyroidism before the enlarged gland is resected. If an abnormal gland is resected, a postoperative calcium and/or PTH level should also be obtained to document adequate resection of presumed parathyroid disease.

●If all four parathyroid glands appear enlarged and the patient is known to be normocalcemic and have normal renal function, vitamin D deficiency should be suspected. Resection of the glands is not recommended.

Parathyroid autotransplantation — A normal-sized parathyroid gland of uncertain viability or an intracapsular/intrathyroidal gland that cannot be sustained by its native vascular pedicle should be autotransplanted into the ipsilateral strap or sternocleidomastoid muscle. In healthy muscle, parathyroid cells can stimulate neovascularization by releasing vascular endothelial growth factor [53]. The technique of parathyroid autotransplantation is described in detail in another topic. (See "Parathyroidectomy in end-stage kidney disease", section on 'Creating an autograft'.)

Autotransplantation should not be performed if a parathyroid gland has obvious tumor involvement. Before transplantation, frozen section of a small portion of the gland may be performed to ensure that the tissue is indeed of parathyroid origin, rather than of a metastatic lymph node or a portion of the thyroid gland. Fine-needle aspiration followed by rapid intraoperative PTH measurement of the aspirate is another way to confirm parathyroid tissue. (See 'Intraoperative frozen section analysis' below and "Intraoperative parathyroid hormone assays", section on 'Identifying parathyroid tissue'.)

Optional techniques and equipment — Intraoperative nerve monitoring and intraoperative frozen section analysis are two optional techniques that can be used to augment thyroid surgery. Drains and vessel sealing devices are optional equipment that can be used to facilitate thyroid surgery.

Intraoperative nerve monitoring — Intraoperative nerve monitoring (IONM) has been advocated with the goal of reducing the rate of RLN injury. Although its routine use remains controversial [6], it could potentially assist in the identification, dissection, and prediction of postoperative function of the RLN [54].

Techniques of nerve monitoring — The two main components of IONM are nerve stimulation and assessment of vocal fold response to nerve stimulation.

Nerve stimulation — The RLN can be stimulated with a low-voltage electric current delivered by a handheld probe (intermittent stimulation) or an electrode attached to the ipsilateral vagus nerve (intermittent or continuous stimulation).

Continuous stimulation could alert the surgeon to an impending nerve injury earlier than intermittent stimulation. However, continuous IONM has the disadvantages of potentially causing vagal neurapraxia (if the electrode dislodges) or hemodynamic instability (eg, cardiac arrest) secondary to increased parasympathetic (vagal) tone [55]. It also requires dissection of structures (eg, vagus nerve) outside of the typical operative field, although a transcutaneous method of vagal stimulation for IONM during endocrine surgery has been reported [56].

Vocal fold response — The vocal fold response to nerve stimulation is most commonly measured by a laryngeal surface electrode system built into or attached to the endotracheal tube [57-59], which is positioned at a level that enables the vocal cords to come into contact with the electrodes [60].

During surgery, the vocal fold response to nerve stimulation is displayed on a nerve monitor as auditory or visual electromyographic (EMG) signals. Changes in the pattern of EMG signals, which can occur with retraction of the gland, dissection of surrounding tissues, or dissection of the RLN itself, can alert the surgeon to possible nerve irritation [57,58].

Because vocal fold response is measured by EMG activities, only short-acting muscle relaxants, such as succinylcholine, should be used during induction of anesthesia when IONM is employed. No paralytic agents should be used after induction to prevent interference with obtaining an EMG signal.

Efficacy of nerve monitoring — Regardless of whether IONM is used during endocrine surgery, surgeons should exercise the same vigilance with surgical techniques to avoid RLN injury. When IONM is used, it is to augment, rather than circumvent, the need for meticulous surgical techniques, including intraoperative visual identification of the RLN.

Most studies examining the utility of IONM have been observational; the few randomized trials were small and underpowered. A 2019 Cochrane systematic review and meta-analysis of five trials found no advantage or disadvantage for IONM in either permanent (relative risk 0.77, 95% CI 0.33-1.77) or transient RLN palsy (relative risk 1.25; 95% CI 0.45-3.47), when compared with visual nerve identification [61]. A 2022 meta-analysis of eight trials similarly found no improvement with IONM in either permanent (IONM 0.5 percent versus visual nerve identification 0.6 percent, p = 0.57) or transient (1.5 versus 2.1 percent, p = 0.11) RLN injury, although there was a nonstatistically significant reduction in overall RLN injury (3.2 versus 2.3 percent, p = 0.069) [62].

Existing data do not support that the routine use of IONM reduces the incidence of RLN injury [59,60,63-68]. IONM, however, may be beneficial in procedures that are either high risk or performed by low-volume surgeons [59,69-71]. High-risk procedures in this context typically include reoperations and those performed for thyroid cancers or goiters (retrosternal or toxic).

During planned total thyroidectomy, after completion of the initial lobectomy if IONM results suggest loss of function, the surgeon may consider stopping the operation for possible completion at a later date [6].

Intraoperative frozen section analysis — In contemporary practice, frozen section analysis is no longer widely used and is only reserved for a few situations in which it could have an impact on surgical decision making [72]:

●To diagnose thyroid malignancies intraoperatively when the preoperative cytology was atypical or suspicious, thus potentially informing the need for a completion thyroidectomy.

●To diagnose lymph node metastasis, which may help guide the decision to perform a therapeutic central compartment neck dissection.

●To confirm parathyroid tissue [73].

Drains — Routine drain placement after thyroid surgery is not necessary [74,75]. A meta-analysis of 11 randomized trials found no significant difference in the incidences of hematoma or seroma formation between routine drainage and no drainage [75].

However, if the thyroid is very large, the dissection is extensive, or the thyroid bed is persistently oozing, a closed suction drain can be placed to prevent fluid collection [75]. The drain can be removed safely without concern for fluid reaccumulation when the output is serous and decreasing in volume.

Vessel sealing devices — Various vessel sealing systems, such as the harmonic scalpel and LigaSure, have been employed successfully in thyroid surgery [76]. The decision to use a vessel sealing device and the choice of the device are based on surgeon and hospital preference [77]. However, just like monopolar electrocautery, vessel sealing devices should not be used within 3 to 5 mm of the RLN to avoid injury.

In a propensity score matched study of over 6500 procedures, the use of a vessel sealing device was associated with a decreased rate of neck hematoma (odds ratio 2.33, 95% CI 1.55-3.49) but no increase in the rate of RLN injuries compared with conventional hemostasis [78].

Minimally invasive thyroid surgery — In general, remote-access thyroidectomy procedures are controversial and should only be performed in carefully selected patients and by surgeons experienced in the approach [6].

●Endoscopic thyroidectomy – Endoscopic or endoscopic-assisted thyroidectomy is also termed minimally invasive video-assisted thyroidectomy (MIVAT). One approach of MIVAT employs small conventional retractors and 2 mm dissecting instruments placed through a small incision in the central neck 2 cm above the sternal notch [79,80]. Hemostasis is achieved by using a harmonic scalpel [79]. Matched comparisons between endoscopic-assisted and conventional thyroidectomy in patients with low- to intermediate-risk papillary thyroid carcinoma showed comparable surgical and oncologic outcomes [80,81]. The main advantage of MIVAT over conventional thyroidectomy is that of a smaller incision. MIVAT has also been performed via transaxillary, retroauricular, and even transoral (experimental) approaches. These alternative approaches do not require a cervical incision [82].

●Robotic surgery – Minimally invasive thyroid surgery can be performed with or without robotic assistance. The robotic technology allows for improved maneuverability of the endoscopic instruments and better ergonomics for the surgeon. However, robotic surgery is associated with a steep learning curve, a significantly longer operating room time, and a higher cost compared with conventional thyroidectomy or minimally invasive thyroid surgery performed without robotic assistance.

Robotic-assisted minimally invasive thyroid surgery is investigational and can be performed via transoral or transaxillary routes in a select subset of patients [83]. In a meta-analysis, robotic thyroidectomy was as safe as open thyroidectomy and was associated with less blood loss, a lower level of swallowing impairment, and better cosmetic satisfaction [84]. The oncologic outcomes for those who have thyroid cancer, however, remain to be determined. In addition, use of the robotic platform for thyroidectomy remains an off-label use of the device.

POSTOPERATIVE CARE

Inpatient versus outpatient surgery — After thyroid surgery, patients may be admitted for overnight observation to manage pain, nausea, or hypocalcemia and to monitor for hematoma formation. Select patients can undergo outpatient thyroid surgery if it is performed by experienced surgeons [85]. In a series of 1168 thyroidectomies, nearly 20 percent were performed as outpatient procedures, mostly by high-volume surgeons at high-volume centers [86]. In that series, the readmission rate after outpatient surgery was comparable to that of inpatient surgery (1.4 versus 2.4 percent).

Pain control — After thyroidectomy, pain is generally reported as minimal in patients who receive preoperative education about the issue. Counseling together with nonopioid (nonsteroidal) and nonpharmacologic therapies should be the first-line management strategy, and if opioids are provided, the lowest effective dose of immediate-release opioids (<10 oral morphine equivalents) should be prescribed [6]. In a trial of 95 patients undergoing thyroid surgery, those treated with nonopioid analgesia (acetaminophen and ibuprofen) had similar pain scores to those treated with opioids up to the first postoperative visit [87]. In another study, over half of the patients did not take opioid medications after cervical endocrine surgery, even though most were prescribed them [88].

Thyroid hormone supplementation — The requirement for thyroid hormone supplementation after thyroid surgery depends upon the patient's diagnosis (benign versus malignant disease) and the extent of their resection (total thyroidectomy versus thyroid lobectomy).

Benign disease except hyperthyroidism — Patients who undergo total thyroidectomy for benign disease are typically started on a daily dose of levothyroxine at approximately 1.6 mcg/kg body weight after surgery. Patients over 65 years should be started at a lower dose; men may require higher doses than women. Approximately six weeks after starting levothyroxine, serum thyroid-stimulating hormone (TSH) should be measured and levothyroxine dose adjusted to keep TSH in the normal range. After that, annual TSH measurements are sufficient for patients who are clinically doing well. Those who display symptoms of either hypo- or hyperthyroidism require further evaluation and adjustment of their medications.

Patients who undergo thyroid lobectomy for benign disease are not routinely started on levothyroxine after surgery, but approximately one-third of them may require levothyroxine supplementation to maintain a normal TSH level. The possibility of permanent hypothyroidism should be discussed with patients prior to any thyroid surgery, including thyroid lobectomy [89]. A TSH level should be obtained approximately six weeks after surgery to determine the need for thyroid hormone replacement. (See "Treatment of primary hypothyroidism in adults".)

Hyperthyroidism — Patients who undergo thyroidectomy for hyperthyroidism require special attention perioperatively. The postoperative management of these patients is discussed in detail elsewhere. (See "Surgical management of hyperthyroidism", section on 'Postoperative management'.)

Malignant disease — The requirement for thyroid hormone replacement in patients who undergo total thyroidectomy for malignant disease depends on the stage of their disease, the aggressiveness of the cancer, and the need for radioiodine ablation (RAI) postoperatively. (See "Differentiated thyroid cancer: Surgical treatment", section on 'Postoperative thyroid hormone therapy'.)

●Patients who are scheduled to receive RAI within two to three weeks of surgery may be discharged home without any thyroid hormone replacement. Thyroid hormone withdrawal raises the TSH level, which stimulates radioiodine uptake and improves the efficacy of RAI. Alternatively, patients may be started on levothyroxine in anticipation of use of recombinant human thyrotropin (rhTSH) prior to RAI.

●Patients who are not scheduled to receive RAI within two or three weeks of surgery may be discharged on liothyronine (T3). Liothyronine is a short-acting thyroid hormone, the level of which can be manipulated to optimize the energy level of the patient. Based on the patient's weight and age, the starting dose of liothyronine is typically 10 to 25 mcg twice a day. Symptoms of dizziness, palpitation, or insomnia may require immediate lowering of the liothyronine dose. Liothyronine is discontinued one to two weeks prior to RAI treatment to induce thyroid hormone withdrawal. (See "Differentiated thyroid cancer: Radioiodine treatment", section on 'Patient preparation'.)

●Another option for patients who have a low-risk differentiated thyroid cancer is to be started on levothyroxine immediately after surgery, followed by recombinant human thyrotropin (rhTSH) just prior to RAI to activate TSH receptors [90]. (See "Differentiated thyroid cancer: Radioiodine treatment", section on 'Recombinant human TSH'.)

After RAI, patients should be maintained on levothyroxine at a daily dose of approximately 1.6 mcg/kg body weight. The actual target of TSH suppression will depend on the patient's age as well as the stage and aggressiveness of the cancer [91]. (See "Differentiated thyroid cancer: Overview of management", section on 'Thyroid hormone suppression'.)

Calcium supplementation — Calcium supplementation after thyroid surgery is typically given orally as calcium carbonate, 1250 to 2500 mg daily total, divided in two to four doses, with the starting dose adjusted and eventually tapered off based on symptoms and/or calcium levels. Patients who take a proton pump inhibitor or have had gastric bypass surgery should take calcium citrate instead due to their lack of gastric acid, which is required for optimal absorption of calcium carbonate.

Intravenous calcium is occasionally required in patients with persistently low calcium levels and symptoms despite oral supplementation. In such patients, peripheral intravenous (IV) infusion sites should be carefully monitored because infiltration of a solution containing calcium can result in soft tissue loss. Patients can be discharged on oral calcium supplementation when their hypocalcemic symptoms resolve and their serum calcium levels stabilize at ≥7.8 mg/dL. (See "Treatment of hypocalcemia".)

Persistent hypocalcemia should also prompt measurement of serum magnesium with repletion if necessary. In a large database study, magnesium disorders were associated with the greatest odds of short- and long-term postoperative hypocalcemia [92].

In addition to calcium, patients with very low or undetectable parathyroid hormone (PTH) levels may need 1,25-dihydroxyvitamin D (calcitriol) to adequately absorb calcium. In such patients, calcitriol can be started prior to thyroid surgery and gradually tapered postoperatively according to the PTH and/or calcium levels [93]. Patients should continue to be monitored for both hypocalcemia (as calcitriol can take 24 to 48 hours to achieve maximal effect) and potential resultant hypercalcemia. If discharged on calcitriol, repeat laboratory tests within three to five days of discharge should be obtained. (See "Treatment of hypocalcemia".)

While all symptomatic hypocalcemia patients require treatment with intravenous or oral calcium, asymptomatic patients may or may not receive calcium supplementation at the surgeon's discretion:

●Some surgeons only prescribe calcium supplementation to patients with low postoperative serum calcium levels and/or low PTH [94-97]. (See "Clinical manifestations of hypocalcemia" and "Diagnostic approach to hypocalcemia" and "Diagnostic approach to hypocalcemia", section on 'Serum PTH concentrations'.)

•In a study of 120 patients who underwent total or near-total thyroidectomy, low total (<7.2 mg/dL) or ionized (<1.0 mmol/L) serum calcium level at 16 hours postoperatively identified 94.5 percent of patients who needed calcium supplementation [95].

•In a prospective study of 143 patients undergoing total thyroidectomy, the 112 patients who had a PTH level ≥10 pg/mL on the first postoperative day were discharged without calcium supplementation; only 10 percent developed hypocalcemic symptoms [94]. By contrast, almost one-half of the other 31 patients who had postoperative day 1 PTH level <10 pg/mL developed hypocalcemia despite some receiving calcium supplementation.

•In another prospective observational study of 123 patients undergoing total or completion thyroidectomy, an 80 percent decrease in intact PTH (iPTH) level postoperatively compared with preoperatively was 100 percent sensitive in predicting clinical hypocalcemia, whereas a postoperative iPTH level of <3 pg/mL was 100 percent specific. Thus, patients with a <80 percent decrease in iPTH, those with an iPTH decrease of ≥80 percent but a postoperative iPTH ≥3 pg/mL, and those with a postoperative iPTH level of <3 pg/mL are at very low, intermediate, and very high risk of developing hypocalcemia, respectively [98].

•However, a 2018 systematic review found that the existing literature regarding the use of PTH levels to predict post-thyroidectomy hypocalcemia is extremely heterogeneous. With a false negative rate as high as 54 percent, and a false positive rate as high as 70 percent, a single PTH threshold may not be a reliable measure of hypocalcemia [99].

●Other surgeons prescribe calcium supplementation routinely to all patients after thyroidectomy to prevent symptoms of hypocalcemia [100]. In a small randomized trial of 79 patients undergoing total thyroidectomy, routine administration of oral calcium and vitamin D reduced both the incidence and severity of hypocalcemia symptoms [93]. In a meta-analysis of 15 studies, routine supplementation with calcium and vitamin D3 after thyroidectomy was associated with a lower risk of symptomatic hypocalcemia (risk difference -0.25, 95% CI -0.32 to -0.18) and biochemical hypocalcemia (risk difference -0.24, 95% CI -0.31 to -0.17) compared with treatment based on measured calcium levels [101].

Follow-up — A follow-up visit should be scheduled in one to two weeks after surgery to:

●Evaluate and manage incisional healing.

●Evaluate the patient for any unusual voice changes, subtle hypocalcemic symptoms, and overall recovery.

●Adjust doses of medications, including those of thyroid hormone replacement and calcium/vitamin D supplementation.

●Review surgical pathology results.

●Discuss plans for further treatment or observation.

●Coordinate multidisciplinary care for patients with thyroid cancer [102].

COMPLICATIONS — Complications of thyroid surgery include wound seroma or hematoma, hypocalcemia due to hypoparathyroidism, hoarseness or change in voice, vocal cord paresis or paralysis due to nerve injury, Horner syndrome, chyle fistula, tracheal or esophageal injury, and dysphagia.

An Italian study of 14,934 patients who underwent thyroid surgery (21 percent lobectomy, 64 percent total thyroidectomy, 9 percent subtotal thyroidectomy, 6 percent reoperation) reported that hemorrhage occurred in 1.2 percent, hypoparathyroidism in 10 percent (8.3 percent transient, 1.7 percent permanent), superior laryngeal nerve injury in 3.7 percent, recurrent laryngeal nerve injury in 3.4 percent (2 percent transient, 1 percent unilateral permanent, 0.4 percent bilateral permanent), and dysphagia in 1.4 percent of patients [38].

In an international study of 2325 patients who underwent surgery for differentiated thyroid cancer, 25.8 percent reported voice changes persisting for longer than three months, 12.7 percent had an abnormal voice handicap index-10 score (VHI-10; which quantifies 10 psychosocial consequences of voice disorder), and 4.7 percent had initial detectable vocal fold motion abnormalities on laryngoscopy [103]. However, this study likely identified transient voice disorders, as permanent dysfunction is defined as lasting for 6 to 12 months.

The reported rates for each complication vary by geography but are generally somewhat considerably lower in the United States (US) than in other countries. Additionally, complication rates, particularly those of nerve injury, hypoparathyroidism, and dysphagia, are also lower in patients operated on by high-volume surgeons and/or at high-volume centers [104-110]. One study found that the likelihood of experiencing a complication after total thyroidectomy decreased when the surgeon performed >25 total thyroidectomies per year [110].

In a study of more than 8000 patients in the US Collaborative Endocrine Surgery Quality Improvement Program (CESQIP), the rates of all emergency room visits and all hospital readmissions were 3.4 and 2.3 percent, respectively [111]. Hypocalcemia was the reason for 22 percent of emergency room visits and 36 percent of the readmissions. Severe obesity, long surgery, and recurrent laryngeal nerve injury were risk factors for return visits.

Hematoma — Postoperative hematoma is a rare but potentially fatal complication of thyroid surgery [38,112-114]. In a retrospective review of 150,012 patients, 1.25 percent developed a postoperative hematoma, and in other studies the rate ranged from 0.7 to 1.5 percent [6,115]. The mortality rate was much higher with a hematoma (1.34 versus 0.32 percent) [114].

To prevent postoperative bleeding and hematoma formation, patients should stop all anticoagulants before surgery; hemostasis must be meticulously maintained during surgery. Additionally, the following conditions have been associated with postoperative hematoma formation by multivariate analyses [114,116]:

●Inflammatory thyroid conditions (odds ratio [OR] 1.59, 95% CI 1.23-2.06)

●Partial thyroidectomy (OR 1.69, 95% CI 1.20-2.37)

●Chronic renal disease (predisposition to bleeding disorders; OR 1.8, 95% CI 1.08-3.03)

●Bleeding disorders (OR 3.38, 95% CI 1.76-6.50) [114]

●Graves' disease (OR 2.43, 95% CI 1.22-4.85 [116]; OR 1.58, 95% 1.09-2.31 [117])

●Benign pathology (OR 2.22, 95% CI 1.35-3.57)

●Antiplatelet/anticoagulation medications (OR 2.12, 95% CI 1.10-4.13)

●Use of a hemostatic agent (OR 1.97, 95% CI 1.21-3.18)

●Use of a drain (OR 2.79, 95% CI 1.68-4.65) [116]

A cervical hematoma is characteristically a large, tense, firm, immobile anterior or lateral cervical swelling under the incision. After surgery, the surgical team should routinely examine the patient for signs or symptoms of a hematoma including wound inspection, pain scoring, as well as being aware of more subtle signs such as discomfort, agitation, anxiety, or difficulty in breathing [118].

Any hematoma that causes airway compromise should be opened at the bedside, for which a post-thyroid surgery emergency box containing essential surgical tools should always be available, including during transfer. We recommend using the SCOOP approach (skin exposure; cut sutures; open skin; open muscles [superficial and deep] layers; pack wound), before the patient is further evaluated and returned to the operating room for formal exploration of a potential source [118].

A post-thyroidectomy hematoma in a patient without immediate concern for airway compromise should be evacuated in the operating room. In a retrospective study of 207 patients who developed a hematoma after thyroidectomy, 79 percent required operating room evacuation within 24 hours of the original surgery. Patients diagnosed with a hematoma should be kept awake and promptly transported to the operating room for evacuation. In the operating room, in most cases the patient's neck should be cleansed with antiseptics, the incision opened, and blood from the hematoma evacuated all prior to intubation, as a large cervical hematoma might make intubation more difficult by compressing the larynx.

Once the airway is secured by intubation, the hematoma should be completely evacuated and hemostasis established with meticulous techniques. The hematoma is usually in the paratracheal area. Thus, the strap muscle closure should be reopened to allow inspection and evacuation of this compartment. The recurrent laryngeal nerves (RLNs) and parathyroid glands should be carefully preserved to avoid a secondary injury; blind use of electrocautery near the ligament of Berry must be avoided. Placement of a drain facilitates prompt evacuation of serous fluid that may accumulate in the bed of the hematoma. Patients may require overnight intubation to allow supraglottic edema to subside before extubation.

Seroma — Wound seromas are typically superficial, mobile, and likely to resolve without any intervention.

Hypocalcemia/hypoparathyroidism — Hypocalcemia is one of the most common complications of thyroidectomy [119]. Symptoms of hypocalcemia range from mild (eg, paresthesias around the lips, mouth, hands, and feet) or moderate (eg, muscle twitches or frank cramps) to severe (eg, trismus or tetany). (See "Clinical manifestations of hypocalcemia".)

While all patients with symptomatic hypocalcemia require oral calcium and some may need to be managed with additional intravenous calcium or calcitriol, asymptomatic patients may or may not need calcium supplementation (at the surgeon's discretion). (See 'Calcium supplementation' above.)

Transient hypoparathyroidism has been reported in 0.3 to 49 percent of patients after thyroidectomy; up to 13 percent of post-thyroidectomy hypoparathyroidism becomes permanent [119]. However, the clinical definition of hypoparathyroidism is controversial, which limits the analysis of its rates after thyroidectomy. We counsel our patients that the risk of permanent hypoparathyroidism after a total thyroidectomy by an experienced surgeon in the United States is approximately 2 percent.

Intraoperative indocyanine green (ICG) angiography has been used in thyroid surgery to predict postoperative hypoparathyroidism. In a randomized trial, none of the 146 patients who had at least one well-perfused parathyroid gland on ICG angiography developed postoperative hypocalcemia with or without laboratory tests and calcium supplementation, which did not affect surgical results. By contrast, 11 of 50 patients who did not have any well-perfused parathyroid gland on ICG angiography developed hypocalcemia on postoperative day 1, and 6 on postoperative days 10 to 15 [120].

Parathyroid tissue, when submitted to near-infrared stimulation, emits a spontaneous autofluorescent signal termed near-infrared-induced autofluorescence (NIRAF). In a European trial (PARAFLUO) of 245 patients undergoing total thyroidectomy, the use of NIRAF intraoperative imaging of the parathyroids resulted in a decrease in the rate of temporary postoperative hypocalcemia (9 versus 22 percent), parathyroid autotransplantation (4 versus 16 percent), and inadvertent parathyroid resection (3 versus 14 percent) [121].

Hoarseness — Hoarseness is common after thyroid surgery. Transient hoarseness that resolves spontaneously in 24 to 48 hours is typically due to vocal cord edema caused by endotracheal intubation. Persistent or severe hoarseness is rare and can be caused by arytenoid dislocation or vocal cord dysfunction from a nerve injury [122-124].

Arytenoid dislocation is an unusual consequence of endotracheal intubation that can cause hoarseness, vocal fatigue, and dysphagia. Arytenoid dislocation should be promptly treated with reduction and repositioning of the arytenoid cartilage [125].

Symptomatic voice changes generally improve after the immediate postoperative period. Hoarseness, uncontrolled coughing when talking, dyspnea that persists for more than 24 to 48 hours after surgery, or aspiration pneumonia should raise suspicion for possible vocal cord motion abnormalities. Such patients should be referred promptly for direct laryngoscopy and a complete neurolaryngeal evaluation [126].

Nerve injury/vocal cord paresis or paralysis — Nerve injury can result from the underlying thyroid disease process, surgery, or anesthesia-related airway manipulation (eg, endotracheal intubation). Three nerves can potentially be injured during thyroid surgery:

●Superior laryngeal nerve (SLN) – Injury to the external branch of the SLN results in voice weakness or fatigue as well as changes to both quality and pitch of the voice [127]. (See 'Superior laryngeal nerve injury' below.)

●Recurrent laryngeal nerve – Injury to the RLN results in the ipsilateral true vocal cord being paretic or paralyzed in a paramedian or lateral position. Intrinsic muscles of the larynx, except the cricothyroid muscle, are denervated, and the patient may have swallowing difficulties and an increased aspiration risk. (See 'Recurrent laryngeal nerve injury' below.)

●Vagus nerve – High transection or injury to the vagus nerve near the carotid bulb paralyzes both the SLN and the RLN. This can result in both sensory and motor deficits of the larynx, which are significant risk factors for aspiration.

Superior laryngeal nerve injury — Isolated SLN injury only produces vocal fatigue and subtle changes in voice quality in timbre, pitch, and voice projection. Due in part to difficulties in accurate diagnosis, rates of SLN injury after thyroidectomy are difficult to determine. In one study, SLN injury was seen after approximately 4 percent of thyroid surgeries [38]. Patients should be counseled preoperatively that they may experience permanent pitch change or have permanent difficulty singing high notes or speaking at a loud volume after surgery.

SLN injury is typically diagnosed with a complete neurolaryngeal evaluation, which could include specialized procedures such as rigid or flexible videostroboscopy or laryngeal electromyography [126]. Aerodynamic assessment of voice production and objective acoustic voice evaluation are also helpful in following improvement over time.

Recurrent laryngeal nerve injury — Iatrogenic injury to the RLN is one of the most concerning complications of thyroid surgery [128]. In various studies, rates of RLN injury ranged from 0 to 7.1 percent for transient injury and 0 to 11 percent for permanent injury; lower rates of RLN injury were achieved by higher-volume surgeons [104-106,129].

Vocal cord paresis — Typically caused by a traction injury to the RLN, vocal cord paresis is usually transient and does not require intervention. However, referral to a voice or speech therapist can help protect the patient's voice, reduce strain, reduce anxiety, and improve vocalization. The vocal cord should typically be reexamined at three and six months. Temporary vocal cord paresis usually resolves by six months. If the vocal cord is immobile for longer than six months, permanent paralysis is likely. (See 'Unilateral vocal cord paralysis' below.)

Unilateral vocal cord paralysis — RLN injury can result in the ipsilateral true vocal cord being paralyzed in a paramedian or lateral position. Medialization of the paralyzed vocal cord improves both swallowing and phonating by allowing the contralateral functioning vocal cord to close off the larynx. A vocal cord paralyzed in the lateral position can be temporarily medialized by injection of fat, silicone, or collagen [130,131]. In patients with permanent deficits (persisting for more than 6 to 12 months after the initial thyroid surgery), collagen can be injected for medialization of the paralyzed vocal cord [131,132].

Early surgical medialization of a paralyzed vocal cord is indicated in patients with severe symptoms such as aspiration pneumonia, disabling breathy hypophonia, ineffective cough, or disabling dyspnea. Patients who have mild symptoms should undergo voice/speech therapy. Those who do not respond to voice/speech therapy after six to nine months and who demonstrate evidence of denervation or little activity on laryngeal electromyography should undergo surgical medialization of the paralyzed vocal cord [133].

Bilateral vocal cord paralysis — Bilateral vocal cord paralysis from injuries to both RLNs is a rare (0.4 percent of cases) but devastating complication of total thyroidectomy that occurs most commonly with reoperations [38]. Bilateral vocal cord paralysis is usually recognized immediately after surgery when the patient develops dyspnea and stridor upon extubation. Immediate reintubation is usually possible, but a tracheostomy may be required if the patient cannot be orotracheally reintubated (eg, if both vocal cords are adducted).

In patients who have permanent bilateral vocal cord paralysis, a partial posterior cordectomy using laser surgery can restore sufficient laryngeal airflow with minimal vocal sequelae and avoid long-term tracheostomy. Bilateral vocal cord paralysis should be managed by a multidisciplinary team for optimal outcomes [126].

Techniques of nerve repair — If an RLN injury is identified intraoperatively, nerve repair should be attempted, when feasible, to promote synkinesis [6,134].

Injured nerves with clean, fresh edges; good hemostasis; and without tension on either end have the best chance of a successful repair. Avulsion or cautery injuries are more difficult to repair than a sharp transection.

The surgical options include direct end-to-end anastomosis (neurorrhaphy), direct implantation of a nerve ending into the thyroarytenoid muscle, or muscle-nerve pedicle grafting using ansa cervicalis. A fine nonabsorbable suture is typically used for the repair.

If the transected nerve appears foreshortened, an interposition nerve graft with a diameter comparable to that of the RLN can be used [135,136]. Commonly used interposition grafts in the neck include the ansa cervicalis nerve and the hypoglossal nerve.

The techniques of nerve repair are discussed in detail elsewhere. (See "Traumatic peripheral neuropathies", section on 'Treatment overview'.)

Dysphagia — Dysphagia is a frequent complaint both before and after thyroid surgery. The etiology of post-thyroidectomy dysphagia is uncertain but may be related to postoperative adhesions, decreased laryngeal elevation, cricothyroid trauma or inflammation, or perithyroidal nerve damage.

Despite an initial decline in the immediate postoperative period, patients without an RLN injury generally experience improvement in their swallowing function at six months after surgery compared with at the preoperative baseline [137], which may be attributed to resolution of compressive symptoms.

In one study, 47 percent of patients who underwent total thyroidectomy had swallowing complaints before surgery, 74 percent during the first week after surgery, and only 20 percent at six months [137]. In another study, 57 percent of patients reported swallowing problems before thyroid surgery, but only 8 percent had persistent symptoms at six months after surgery [138]. Anecdotally, incisional massage may greatly improve postoperative dysphagia.

Horner syndrome — Horner syndrome is a neurologic syndrome caused by disruption of the sympathetic pathway that supplies the head, eye, and neck. The symptoms of Horner syndrome are miosis, ptosis, and anhidrosis. Horner syndrome is a very rare (0.2 percent) complication of thyroidectomy that is most often associated with a lateral neck dissection [139]. The sympathetic chain can be disrupted due to ischemic nerve damage, stretching of the cervical sympathetic chain by the retractor, or postoperative hematoma. Injury to the sympathetic chains can be minimized with careful dissection around the prevertebral fascia and carotid sheath. (See "Horner syndrome".)

Chyle leak — Chyle leaks or fistulas are caused by injury to the thoracic duct. Chyle leak is reported in 1.8 to 8.3 percent of thyroidectomies. Although chyle leak occurs most often when a lateral lymph node dissection has been performed [140], it can occur with central neck dissection as well [141]. (See "Etiology, clinical presentation, and diagnosis of chylothorax".)

Chyle leaks can lead to severe fluid and electrolyte imbalances and even death if not treated properly. They are generally indicated by milky drainage, a bulging supraclavicular fossa, and induration or erythema of the skin. Low-output chyle leak (<500 mL/day) can be managed conservatively with fasting [141]; high-output leaks require surgical ligation of the thoracic duct [140].

Tracheal injury — Tracheal necrosis secondary to excessive use of cautery on or around the trachea is a rare complication of thyroidectomy [142]. The blood supply to the upper trachea is primarily from small branches of the inferior thyroid artery, which could be damaged during thyroid surgery. Tracheal necrosis can lead to air leak or subcutaneous emphysema and is potentially life-threatening. Any tracheal injury requires neck reexploration and construction of a tracheostomy. (See "Tracheostomy: Rationale, indications, and contraindications".)

Esophageal injury — While rare, esophageal and pharyngeal injury can occur with thyroid surgery. The finding of extensive crepitus in the neck postoperatively should prompt immediate evaluation for a pharyngeal or esophageal perforation. (See "Overview of esophageal injury due to blunt or penetrating trauma in adults".)

SOCIETY GUIDELINE LINKS — Links to society and government-sponsored guidelines from selected countries and regions around the world are provided separately. (See "Society guideline links: Thyroid surgery".)

INFORMATION FOR PATIENTS — UpToDate offers two types of patient education materials, "The Basics" and "Beyond the Basics." The Basics patient education pieces are written in plain language, at the 5^th to 6^th grade reading level, and they answer the four or five key questions a patient might have about a given condition. These articles are best for patients who want a general overview and who prefer short, easy-to-read materials. Beyond the Basics patient education pieces are longer, more sophisticated, and more detailed. These articles are written at the 10^th to 12^th grade reading level and are best for patients who want in-depth information and are comfortable with some medical jargon.

Here are the patient education articles that are relevant to this topic. We encourage you to print or e-mail these topics to your patients. (You can also locate patient education articles on a variety of subjects by searching on "patient info" and the keyword(s) of interest.)

●Basics topics (see "Patient education: Seroma (The Basics)")

SUMMARY AND RECOMMENDATIONS

●Preoperative evaluation – Thyroidectomy is usually an elective operation, and any major medical issues should be addressed before proceeding to surgery. (See 'Preoperative evaluation and preparation' above.)

•Patients with hyperthyroidism should be medically optimized with antithyroid medications and/or a beta blocker prior to thyroid surgery to avoid thyroid storm. (See "Surgical management of hyperthyroidism", section on 'Preoperative preparation'.)

•Diagnostic thyroid ultrasound should be performed in all patients with a suspected malignancy, thyroid nodule, nodular goiter, or abnormality detected on other imaging modalities. Imaging modalities such as computed tomography (CT) or magnetic resonance imaging (MRI) should be reserved for the assessment of patients with extensive extrathyroidal disease. (See 'Preoperative evaluation and preparation' above.)

•Preoperative laryngoscopy or laryngeal ultrasound should be performed for patients with preoperative hoarseness or voice changes, extrathyroidal disease extension, or bulky lymphadenopathy and for all patients undergoing reoperative surgery. (See 'Preoperative evaluation and preparation' above.)

●Intraoperative recurrent laryngeal nerve protection – Routine visual identification of the recurrent laryngeal nerve (RLN) decreases the incidence of injury and is regarded as the standard of care in thyroid surgery. Intraoperative nerve monitoring is an adjunctive measure that can be used to identify the nerve with the goal of reducing the risk of nerve injury but should not be relied upon as a substitute for good surgical technique. (See 'Dissection of the thyroid gland' above and 'Intraoperative nerve monitoring' above.)

●Intraoperative frozen section analysis – Frozen section analysis during thyroid surgery should only be employed when it will have an impact on surgical decision making. (See 'Intraoperative frozen section analysis' above.)

●Postoperative management – The requirement for immediate thyroid hormone supplementation after thyroid surgery depends upon the patient's diagnosis (benign versus malignant) and the extent of their resection (total thyroidectomy versus thyroid lobectomy). (See 'Thyroid hormone supplementation' above.)

•Patients undergoing total thyroidectomy are at risk for developing transient or permanent hypoparathyroidism postoperatively. Some surgeons prescribe calcium supplementation routinely after thyroidectomy to prevent symptoms of hypocalcemia, whereas others do so selectively based upon postoperative serum calcium levels. Patients should be counseled to promptly report hypocalcemic symptoms such as circumoral paresthesias. (See 'Calcium supplementation' above.)

•Hoarseness, uncontrolled coughing when the patient is talking, dyspnea persisting for more than 24 to 48 hours after thyroid surgery, or aspiration pneumonia should raise suspicion of potential vocal cord paralysis as a result of an RLN injury. Such patients should be evaluated promptly, including direct laryngoscopy. (See 'Hoarseness' above and 'Nerve injury/vocal cord paresis or paralysis' above.)