Thyroidectomy

Updated: Apr 03, 2017
  • Author: Neerav Goyal, MD, MPH; Chief Editor: Arlen D Meyers, MD, MBA  more...
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Overview

Overview

Introduction

The thyroid gland has been described throughout history but was first so named by the Romans for being a "shield-shaped" gland. Not only were thyroid masses mentioned in the literature throughout the 12th and 13th century, but in 1170 Robert Frugardi described the extirpation of a goiter. Thyroid surgery was undertaken well before thyroid gland physiology was understood. The procedures were often fraught with complications, including massive hemorrhage, infection, and injury to surrounding structures, all of which were associated with morbidity and mortality rates of nearly 40%.

Even in the 19th century, thyroid surgery was considered barbaric, described by Samuel Gross as "horrid butchery," and banned by the French medical society due to its high mortality. As technology improved and with the advent of aseptic technique, mortalities associated with these surgeries decreased. [1] During the 1850s, operations on the thyroid gland were undertaken via longitudinal, oblique, or vertical neck incisions. Jules Boeckel of Strasbourg introduced the collar incision to thyroid surgery in 1880, and this approach was popularized by Theodore Kocher. Theodor Kocher, whose own reported mortality rate for thyroidectomy dropped to 1%, was awarded the Nobel Prize in 1909 for his advancement of thyroid surgery in the late 19th century. [2, 3]

The surgical technique of thyroidectomy, as well as adjunct technology, continued to advance. Most recently, various new instruments (ie, harmonic technology) and approaches including video-assisted thyroidectomy and robot-assisted thyroidectomy have emerged. This chapter discusses the preoperative evaluation, intraoperative considerations, surgical technique(s), and postoperative concerns for patients undergoing thyroidectomy.

Indications

Various indications for thyroidectomy exist. One of the major indications is a diagnosis of thyroid cancer, usually biopsy-proven by fine-needle aspiration of a nodule.

Although the full range of thyroid nodule histology is beyond the scope of this chapter, the histology can have significant ramifications as to chosen operative management. In patients with all but the most minimal (low-risk) biopsy-proven papillary thyroid cancer, and all medullary thyroid cancer, a total thyroidectomy is indicated. Patients with a fine-needle aspiration showing either Hürthle cells or follicular neoplasm require at least a thyroid lobectomy of the side ipsilateral to the nodule and possibly a total thyroidectomy if the permanent operative specimen shows signs of malignancy. In addition to these malignancies, anaplastic thyroid cancer can occasionally be an indication for thyroidectomy, if no significant extension and infiltration into the surrounding structures is found. [4]

Beyond malignancies, thyroidectomy is also a viable option for patients with symptomatic thyroid masses or goiters. Patients who have compressive symptoms including dysphagia, dyspnea, shortness of breath, and/or hoarseness due to a large goiter should undergo a thyroidectomy. Usually dysphagia to solids is the earliest presenting symptom. Aesthetic concerns due to a goiter may be an indication for thyroidectomy. Another indication includes patients with medically refractory Graves disease or hyperthyroidism. [5]

Contraindications

Uncontrolled severe hyperthyroidism (ie, Graves disease) is a relative contraindication to surgery due to concerns for intraoperative or postoperative thyroid storm. Although thyroidectomy can be performed during pregnancy for malignancy, many authors cite postponing surgery until after delivery if possible, secondary to risks to the fetus from the anesthesia. Indications for surgery during pregnancy include aggressive cancers or airway compromise. If elective thyroid surgery is undertaken during pregnancy, it should be performed during the second trimester if possible. [6, 7]

Anatomy of the thyroid gland

The thyroid gland starts developing on approximately the 24th day of gestation from endodermal epithelial cells on the median surface of the pharyngeal floor—the foramen cecum. It develops caudal to the median tongue bud, which arises from the first pharyngeal arch, and rostral to the copula, which develops from the second pharyngeal pouch. By the seventh gestational week, the thyroid gland descends anterior to the hyoid bone, thyroid cartilage, and cricoids cartilage to rest anterior to the trachea. The path of descent is marked by the thyroglossal duct, a tubular structure of thyroid tissue, that usually obliterates completely between the 7th and 10th gestational week. However, a persistence of the inferior-most aspect of this duct is present in as many as 50% of patients in the form of the pyramidal lobe. [8, 9]

Thyroid embryology. Thyroid embryology.

The fully developed thyroid gland is composed of 2 lateral lobes and a central isthmus with or without a pyramidal lobe (40-50%). The thyroid lies in the middle layer of the deep cervical fascia and is attached from its superior-medial aspect to the thyroid and cricoid cartilages via the anterior suspensory ligament. Berry’s ligament (the posterior suspensory ligament) connects the posterior-medial aspect to the first and second tracheal ring and the cricoid cartilage. The sternohyoid and sternothyroid muscles cover the thyroid gland anteriorly. The tubercle of Zuckerkandl extends off of the posterior and lateral aspect of the thyroid lobes. [8, 9]

The thyroid gland is a very vascular structure. The major arterial contributions are the superior thyroid artery, a branch off of the external carotid artery, and the inferior thyroid artery, which branches off of the thyrocervical trunk. Lastly, the thyroidea ima artery can provide an arterial supply through the inferior border of the isthmus in 2-12% of patients. [10] It branches from either the innominate, subclavian, right common carotid, internal mammary, or the aortic arch.

Thyroid anatomy. Thyroid anatomy.

The superior, middle, and inferior thyroid veins provide venous drainage and join either the internal jugular or innominate veins. The superior thyroid vein follows the pathway of the superior thyroid artery. The middle thyroid veins directly flow into the internal jugular vein. The inferior thyroid veins can be found just anterior to the trachea and often anastomose with each other. Lymphatic drainage tends to follow venous drainage and leads to the prelaryngeal, pretracheal, paratracheal, and supraclavicular nodes. The gland is innervated by the superior, middle, and inferior cervical ganglia of the sympathetic trunk, as well as by parasympathetic fibers from the vagus nerve. [8, 9]

Anatomy of the parathyroid glands

The parathyroid glands develop from the third and fourth pharyngeal pouches. The inferior parathyroid glands develop from the third pouch and descend at week 7 with the thymus to eventually rest at the dorsal surface of the thyroid gland outside of the thyroid capsule. The superior parathyroids develop from the fourth pouch and descend with the thyroid gland. The superior parathyroid glands are usually posterior to the inferior glands, and, as noted in the figure, they usually lie posterior to the plane of the recurrent laryngeal nerve.

Accessory parathyroid glands, as noted by Munck and Eisele, occur 3-7% and fewer than 4 glands are present in 3-6% of patients. [11] Gland descent is usually symmetric, and contralateral glands are usually located at the same level. Aberrant or ectopic glands can also be present if the glands descend incompletely or too far. Possible locations for parathyroid glands include the anterior or posterior mediastinum, carotid bifurcation, as well as the retroesophageal, retropharyngeal, or retrolaryngeal regions. The vascular supply for the parathyroid glands is usually from the inferior thyroid artery, although occasionally the superior glands are supplied by an anastomosis between the inferior and superior parathyroid arteries. [8]

Parathyroid anatomy. Parathyroid anatomy.

Anatomy of the recurrent laryngeal nerve

The recurrent laryngeal nerve branches off the vagus nerve and is present by the sixth gestational week, associated with the sixth branchial arch. Because the aortic arches are cranial to the larynx at this stage, the nerve does not loop at this point. As the larynx moves cephalad, the recurrent nerve also ascends. Although the distal portion of the sixth aortic arch degenerates on the right, it persists in the left as the ductus arteriosus. For this reason, the left recurrent laryngeal nerve stays below the ductus arteriosus and ascends to the larynx.

On the right, the nerve ascends with the larynx until it reaches the fourth aortic arch (the subclavian artery). In approximately 1% of the population, the right subclavian arises from posterior to the esophagus, allowing the right recurrent laryngeal nerve to ascend further and enter the larynx directly without forming a loop. Additionally, the loops of the recurrent laryngeal nerves can be reversed in patients with a right-sided aortic arch. [8]

Recurrent laryngeal nerve anatomy. Recurrent laryngeal nerve anatomy.

The left recurrent laryngeal nerve begins a course that is parallel and close to the tracheoesophageal groove at a more inferior position than the right nerve. The right nerve, on the other hand, angles toward the tracheoesophageal groove before running parallel to it. The middle portion of the recurrent nerve is often in close proximity to Berry's ligament, with some papers describing its course as penetrating through the ligament. [12] Both nerves follow the inferior thyroid artery, and, as it approaches the thyroid gland, they can be found either anterior to the artery, between branches of the artery, or posterior to the artery.

Berry's ligament. Berry's ligament.
Inferior thyroid/recurrent laryngeal nerve relatio Inferior thyroid/recurrent laryngeal nerve relationship.

Occasionally, the nerves branches prior to entering the thyroid gland into motor and sensory components. Additionally, a branch of the nerve ascends and anastomoses with the superior laryngeal nerve to form the Galen anastomosis. [9, 13]

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Preparation

Preoperative workup

For thyroid nodules, the patient should have a thyroid ultrasound, and a fine-needle aspiration should be performed for large or suspicious nodules. Those with lesions suspicious for papillary or medullary thyroid cancer should also have an ultrasound performed of the lateral neck compartments to be evaluated for metastatic disease.

CT imaging of the neck is helpful, especially in patients with significant goiters, to rule out substernal extension. Note that contrast-enhanced scans can limit the ability to provide radioactive iodine in patients with iodine-avid tumors. [14, 15]

Additionally, all patients undergoing thyroidectomy should have their vocal cord function evaluated and documented prior to surgery.

Equipment

A basic head and neck set, to include the following, is necessary:

  • #3 knife handle
  • #15 blade
  • Adson tissue forceps with and without teeth
  • DeBakey forceps
  • Halsted mosquito forceps
  • Reinhoff swan neck clamp (or Burlisher clamp)
  • Allis tissue forceps
  • Richardson retractor
  • Peanut/Kittner sponges
  • Double-pronged skin hooks
  • Mahorner retractor (alternatively, other self-retaining retractors may be used)
  • Bovie electrocautery, harmonic scalpel , and/or Shaw scalpel
  • Bipolar electrocautery forceps
  • If intraoperative neural monitoring is to be performed, nerve monitoring Leads and surface electrode primed endotracheal tube
  • Nerve Stimulator

Anesthesia

Thyroidectomy under regional or local anesthetic may be performed safely if necessary; most cases, however, are performed under general anesthesia with endotracheal intubation.

Positioning

The patient should be placed in a supine position with the apex of the patient’s head at the top of the operating bed. A shoulder roll or gel pad should be placed at the level of the acromion process of the scapula to help extend the neck. Care should be taken to avoid hyperextension of the neck, and the head should be supported to provide maximal exposure of the surgical field without hyperextension. The patient’s arms should be gently tucked by either side. After intubation, the bed can either be rotated 180º from the anesthesiologists or sufficiently moved away from their machines to provide a maximal work area.

Marking

The following key anatomic locations should be found by superficial palpation and marked with a marking pen:

  • Thyroid notch
  • Cricoid cartilage
  • Superior edge of clavicles
  • Sternal notch

Traditionally, a collar incision is used. The incision should be created in a curvilinear fashion within a skin crease approximately 2 cm or 2 finger-breadths above the superior edge of the clavicle and sternal notch. Although smaller incisions lengths have been described, in the authors' experience, an incision length of between 6 cm and 8 cm is used to allow for adequate exposure without causing stretch injury to the surrounding skin. [2]

Intraoperative nerve monitoring

Some controversy still remains with regard to the use of intraoperative recurrent laryngeal nerve monitoring. Although strong anatomic knowledge is a prerequisite to any surgery, the use of intraoperative nerve monitoring allows for an intraoperative assessment of nerve function prior to removing the gland, immediately after removing the gland, and just prior to closure of the surgical site. The use of recurrent laryngeal nerve monitoring has been described since the 1970s and has evolved from intramuscular electrodes to the currently used endotracheal tubes, which have integrated surface electrodes that contact the vocal cords. [16]

Opponents to nerve monitoring cite the increased cost and set up in the operating room, as well as the risk of false positives and negatives. They also note that nerve monitoring does not reduce the rate of RLN palsy. [17]

However, studies show that while intraoperative nerve monitoring may not have a significant difference in reducing nerve injury, the presence of monitoring can be used to predict how well the nerve functions postoperatively. Choby et al describes normative values for in-situ nerve stimulation pre and post thyroidectomy. [18] Donnellan et al further describes prospective nerve stimulation thresholds and compares thresholds seen in patients with normal and abnormal vocal cord function. They conclude that there is an association between lower (≤0.5mA) stimulation thresholds and normal vocal cord function. [19]

This can have an impact on surgical management of patients undergoing total thyroidectomy for a benign condition, should one nerve not stimulate well during the case. [20]

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Technique

Overview

The technique described refers to a capsular dissection of a thyroid lobe, which can be extended to a total thyroidectomy. Prior to the advent of a capsular dissection, the literature describes the use of nodulectomies, wedge resections, and subtotal thyroidectomy to treat thyroid nodules and thyroid cancer.

The literature describes a variety of techniques to perform the dissection, including sharp dissection with vessel suture ligation, electric cautery, as well as the use of electric and ultrasonic scalpels. A recent phase IV multicenter trial evaluated the use of the electric and ultrasonic scalpel use in performing thyroidectomies and found an associated lower operative time with similar postoperative complication rates and cost. [21]

Incision and exposure of the thyroid gland

The initial incision is made over the marked line as described in the preparation section. A #15 blade is used to incise through the epidermis and dermis. Using a Shaw scalpel or monopolar cautery, dissection is carried through the subcutaneous fat to the platysma. Once the level of the platysma has been identified along the length of the incision, the platysma is incised. Using the double-pronged skin hooks and the Shaw scalpel or monopolar cautery, subplatysmal flaps are elevated superiorly and inferiorly. After elevating the subplatysmal flaps, the Mahorner or alternative self-retaining retractor may be inserted. Care should be taken to not lacerate or damage the skin edges with the retractor.

The strap muscles (sternohyoid and sternothyroid) should then be identified. In the midline between the strap muscles, the cervical linea alba can be identified. Once identified, bluntly dissect through this fascia. The Harmonic scalpel or monopolar cautery can then be used to dissect through this fascia superiorly and inferiorly along the length of the sternohyoid muscle. In cases of large goiter or neoplasm, the strap muscles may be divided to aid exposure. Division of the strap muscles should be performed high (cephalad), as the innervation of the strap muscles occurs more inferiorly. Just deep to this dissection lies the thyroid gland, and overlying fascia should be easily identified.

Cervical linea alba. Cervical linea alba.

Releasing the superior pole

Once the thyroid gland is identified, attention should be turned to a single lobe. Using the Richardson retractors and blunt dissection, capsular dissection should be carried to the lateral aspect of the thyroid lobe, where it meets the carotid sheath fascia. Once the lateral border of the dissection has been performed, the carotid artery identified, blunt dissection may be carried out superiorly.

At the superior pole, care should be taken to dissect the overlying strap muscles off of the thyroid gland without injuring the subcapsular vessels. Next, the cricothyroid space should be identified and dissected. By retracting the thyroid inferiorly and medially, and using a small Richardson retractor to retract the strap muscles superiorly and laterally, the surgeon can allow for maximal visualization of the superior pole of the thyroid. After dissecting both laterally and medially (cricothyroid space) to the superior pole, the superior pedicle can be divided using either a Harmonic scalpel, clips, or ties. Care should be taken to avoid injuring the external branch of the superior thyroid nerve.

Cricothyroid space. Cricothyroid space.
Exposure of the superior pole. Exposure of the superior pole.

Identifying the parathyroid glands

Once the dissection of the posterior aspect of the thyroid lobe begins, the surgeon and assistants should be vigilant in identifying the parathyroid glands. The superior parathyroid gland can often be found cephalad to the tubercle of Zuckerkandl and can also be found adjacent to the superior pole. The inferior parathyroid gland is usually located in a 1 cm radius around the inferior pole of the thyroid gland and almost always anterior to the plane of the recurrent laryngeal nerve. Of note, 3-7% of patients may have supernumerary glands. [16] After identifying the glands, they should be carefully dissected from the thyroid and left in the thyroid bed.

Identifying the recurrent laryngeal nerve

As described in the anatomy section, slight variations in the anatomy and location of the recurrent laryngeal nerves (RLNs) can exist. During surgery, a few anatomic landmarks can assist in identification of the nerves. The Tubercle of Zuckerkandl marks the posterolateral aspect of the thyroid lobe and is most often found lateral to the recurrent laryngeal nerve. The tubercle can be found in 80% of thyroids and when found can lead directly to the recurrent laryngeal nerve, as 93% of the nerves are found medial to this tubercle. [22, 23] Most often, the nerve is found in a groove between the tubercle and the lobe of the thyroid gland. [24]

As described before, both the left and right nerve follow closely with the course of the inferior thyroid artery, and this landmark can also help identify the nerve. Veyseller et al compared identifying the nerve from a superior-to-inferior approach (from its insertion into the larynx) to an inferior-to-superior approach (identification at the inferior pole) and found a lower rate of hypoparathyroidism using the superior-to-inferior approach for identifying the RLN. However, while this was a prospective trial, it was not randomized and could be confounded by both surgeon preference/experience and the indication for the thyroidectomy. [25]

Of note, many variations of the anatomic relationship between the artery and the nerves exist. Additionally, Berry’s ligament can be used for identification, since the nerves are found in close proximity to the ligament; however, the literature describes various anatomic relationships between the 2 structures. [12]

Berlin described the nerve penetrating the ligament in 25% of cases; however, a recent study by Sasou et al described 24 cases showing the nerve travelling posteriorly and dorsally to the ligament. [26] The inferior thyroid artery can also be used as a landmark for the RLN, with its close association with the pathway of the nerve. Again variations exist, and the branches of the inferior thyroid artery can be anterior or posterior to the nerve, or the nerve can run in between the branches of the artery.

Once the nerve is identified anatomically, its identity and integrity may be confirmed with nerve stimulation. A threshold value may be obtained to determine the minimum current necessary to stimulate the nerve. The course of the nerve should be bluntly dissected using the Reinhoff or a right angle clamp. A sufficient portion of the nerve should be dissected to ensure its safety during dissection and removal of the thyroid gland. Of note, too extensive of a dissection of the nerve can increase the risk of neurapraxia or injury to the nerve.

Recurrent laryngeal nerve. Recurrent laryngeal nerve.

Removing the thyroid gland

After identifying and stimulating the recurrent laryngeal nerve, the thyroid gland can be removed. Berry’s ligament defines the posterolateral attachment of the thyroid gland. Blunt dissection can be used to further expose this fascial attachment. Then a harmonic scalpel can be used to transect the ligament. Often, a minimal amount of thyroid tissue is left adjacent to the entrance of the recurrent laryngeal nerve into the larynx, to reduce the risk of injuring the nerve.

If the patient is undergoing a total thyroidectomy, attention should first be turned to the opposite thyroid lobe and recurrent laryngeal nerve. Once the entire specimen has been dissected and is only attached posteriorly to the pretracheal fascia, it can be removed. The removed specimen should be inspected.

Closure

Obtaining hemostasis in the thyroid bed is imperative. This is best performed with selective bipolar cautery, especially in the vicinity of the recurrent laryngeal nerve. A thin layer of thrombin mesh may be applied to the superior aspect of the bed. The usage of drains is controversial and the authors do not feel that they are routinely necessary. Note that drain usage does not replace meticulous hemostasis nor prevent hematoma accumulation. If a large defect or void exists following thyroidectomy, especially in patients with large goiters, a suction drain may be placed. The neck is then closed in a layered fashion with special attention to a meticulous skin closure.

Thyroid lobectomy performed using the described technique.

Alternative techniques/methods: minimally invasive video-assisted thyroidectomy

The current standard surgical technique was developed by Miccoli at the University of Pisa and brought to North America by Terris et al. [27, 28] The approach uses endoscopes and endoscopic instrumentation through a 15-20 mm incision. Current authors indicate a steep learning curve associated with the technique, as well as the need for a second assistant in the procedure; however, Miccoli did demonstrate a significant reduction in operative time after 30 cases.

Careful patient selection is required to ensure feasibility of this approach. Recent studies describe decreased postoperative pain, faster recovery, as well as improved cosmetic outcome as compared to conventional surgery, but with increased operative time. A meta-analysis of the currently published randomized controlled trials (total n=318, 5 trials) confirmed these differences (although it did not compare recovery time). [29] A recent cost-effective analysis in South Carolina described equal costs between the 2 approaches. [30]

Alternative techniques/methods: robotic-assisted thyroidectomy

With the increasing prevalence of robotic surgery programs, more varied applications for the system have been described. To avoid a neck incision for thyroidectomy, transaxillary approaches have been described and is being used in some centers. As an extension of this approach, a transaxillary approach using the DaVinci robotic system was devised by Kang et al. Using a 4-6 cm axillary incision and an 8 mm medial skin incision, the surgeon introduces 4 robotic arms to perform the thyroidectomy and then follows the same steps as a conventional thyroidectomy. Although achieving a better cosmetic result without an incision on the neck, the technique is more invasive with a wider dissection necessary. A total thyroidectomy through a single sided transaxillary incision provides significant technical difficulties. With the significant expense of using a robotic system, the operation may be cost prohibitive. [31]

Another robot-assisted technique has been described more recently using a traditional postauricular rhytidectomy incision. This is described as a single-port technique and has been performed in appropriately selected patients (low body mass index, no previous neck surgery, no significant comorbidities). Terris et al described a case series with operative times ranging from 97-193 minutes and all but the first patient being performed on in an outpatient setting. [32]

Other Considerations: substernal goiter

Some patients that present with compressive symptoms and an enlarged thyroid demonstrate substernal extension of their goiter either on physical examination, ultrasound, or CT imaging. The technique and approach for removing these goiters is very similar to a conventional thyroidectomy. Because the goiters originate in the neck, they rarely have a mediastinal blood supply.

Most often, removing substernal goiters does not require a sternotomy; instead, they can be removed by digital dissection along the thyroid capsule. These patients are at an increased risk of recurrent laryngeal nerve injury, with reports as high as 17.5%. Randolph et al found that sternotomy was indicated in patients who had superior vena cava syndrome, a goiter with mediastinal blood supply, a posterior mediastinal goiter, a larger diameter to the intrathoracic component, recurrent substernal goiters, malignancy extending into the mediastinum, or the presence of significant adhesions to mediastinal vessels or pleura. [33]

Other considerations: reoperative/revision thyroid surgery

In patients who initially had a hemithyroidectomy for a follicular adenoma seen on fine-needle aspiration, a chance exists that the surgical specimen pathology will yield a follicular adenocarcinoma. Additionally, with the prevalence of subtotal thyroidectomy until the 1970s, a population of patients may need reoperative thyroidectomy for recurrent benign or malignant conditions. Additionally, patients may need revision thyroid surgery if they present with paratracheal, central compartment, or lateral neck nodes. One of the significant challenges presented by a reoperative or revision surgery is the scarring present from the prior violation of the neck. [34]

For patients needing completion thyroidectomy, some surgeons advocate for early intervention within 5-7 days after the first operation, before significant inflammation and scarring occur in the surgical bed. Others argue that the surgery should occur 2-3 months later when induration in the area is reduced.

A preoperative evaluation including imaging and reviewing previous operative reports can help with surgical planning. Ultrasound can help localize recurrent disease or suspicious masses, while a CT scan or MRI can give better delineation of surgical planes. As mentioned before, the use of CT scanning with contrast should be discussed with the multidisciplinary team if radioactive iodine may be used postoperatively. If significant scarring exists, one can consider using a trap door technique, in which dissection is carried from the lateral border of the thyroid medially to the central compartment.

The parathyroid glands as well as the recurrent laryngeal nerves are especially at risk during revision thyroid surgery. Care should be taken to not avulse the vasculature of the parathyroids, and the inferior thyroid artery branches should be ligated one by one and not together to avoid injuring the branches supplying the parathyroids. Additionally, the surgeon should be prepared to autoimplant parathyroid tissue should an avulsion occur. [35, 34]

Terris et al describes a population of 321 patients undergoing reoperative surgery under experienced hands for benign thyroid disease. In this population, no patient suffered transient or permanent RLN injury from the reoperative surgery and one patient had temporary hypoparathyroidism. [36]

In a review by Ruggiero and Fedok, the complication rates for reoperation for both well-differentiated thyroid cancer as well as medullary thyroid cancer were described and found to be higher. Although generally regarded as safe, and with the suggestion that intraoperative nerve monitoring may provide benefit, [37] the overall complication rates were directly correlated to the degree of aggressiveness with the second operation. [38]

Other considerations: parathyroid autoimplantation

In the event of accidental avulsion of a parathyroid gland or compromising its blood supply, the effected parathyroid gland should be removed and placed within a specimen cup on ice. A portion of the removed tissue should be sent for frozen section to confirm it to be in fact parathyroid tissue. The surgeon should then consider auto-implantation of the gland.

The parathyroid gland specimen should be minced into small 1-2 mm pieces and placed in a muscular pocket. Auto-implantation is described in the forearm or the sternocleidomastoid muscle. When implanting into the sternocleidomastoid muscle, a small pocket should be made within the muscle fibers. A nonabsorbable radio-opaque marker, such as a surgical clip, can be used to identify this location in the event of future surgical intervention.

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Post-Procedure

Immediate postoperative course

In the authors' practice, patients who have undergone thyroidectomy remain overnight for a 23-hour stay. Some surgeons perform thyroid surgery on an outpatient basis. [39] Patients who undergo a total thyroidectomy have their calcium levels monitored for iatrogenic hypoparathyroidism. Recent studies have compared the use of postoperative parathyroid hormone as an adjunct or replacement to measuring serum calcium levels in predicting hypoparathyroidism. Al-Dhahri et al describes the use of postoperative PTH 6 hours after surgery with a cutoff of 1.7 pmol/L as being more accurate at predicting which patients are at risk for hypocalcemia. [40] Graff et al, on the other hand, note that a PTH value less than 14 pg/mL was 100% sensitive and 83% specific, while combining this value with a postoperative serum calcium raised specificity to 88%. [41]

Long-term monitoring

Patients undergoing a total thyroidectomy are iatrogenically hypothyroid following the operation. Medical management of hypothyroidism and continued monitoring are imperative. Those patients with thyroid cancer should also be monitored for disease recurrence.

Patient education

Before discharge, patients should be instructed on proper incision care as well as given information on signs of hypocalcemia (ie, numbness or tingling of the digits or perioral area). Additionally, they should be made aware of neck hematoma as a possible complication and the signs to observe. For incision care, hydrogen peroxide and petroleum jelly can be applied to the incisions twice a day. Should patients develop neck swelling or difficulty breathing, they should go immediately to the nearest emergency room.

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Complications

Hypocalcemia secondary to hypoparathyroidism

Reported rates of transient hypocalcemia vary in the literature from between 5-50%, but the rate of permanent hypocalcemia secondary to hypoparathyroidism (ie, lasting more than 6 months) is between 0.5-2%. The pathophysiology behind transient hypoparathyroidism and hypocalcemia is not well understood but is thought to be related to a transient ischemia to the parathyroid glands or perhaps an increased release of the acute phase reactant endothelin 1. [42] A systematic review of predictors of post-thyroidectomy hypocalcaemia found perioperative parathyroid hormone (PTH), preoperative vitamin D and postoperative changes in calcium to be biochemical predictors. [43] Patients who are at increased risk for this complication are those with Graves disease or malignancy or those undergoing total thyroidectomy, or total thyroidectomy with central compartment neck dissection.

Patients may initially be asymptomatic while hypocalcemic. Classic presenting symptoms include numbness and tingling of the digits or perioral area, carpopedal spasm, or the presence of a Chvostek sign or a Trousseau sign. In severe cases, patients may also experience tetany, EKG changes (QT prolongation), seizures, mental status changes, or cardiac arrest secondary to hypocalcemia. The Chvostek sign can be reproduced by tapping on the face just anterior to the ear, causing contraction of the ipsilateral facial muscles. A patient with a positive Trousseau sign will have spasm of the wrist, fingers, or thumb with inflation of a sphygmomanometer above the systolic blood pressure. Either sign is indicative of neuromuscular excitability associated with hypocalcemia.

Patients who are noted to have postoperative hypocalcemia should be managed with calcium supplementation. By following the trend of serum calcium levels, oral calcium supplementation can be titrated accordingly. If patients are receiving 2 grams of elemental calcium and continue to have decreasing or low serum calcium, calcitriol supplementation between 0.25-1 mcg per day can be considered. Additionally, intravenous calcium replacement may be necessary for patients refractory to oral management or those with severe symptomatic hypocalcemia. Endocrinology consultation should be considered in these patients. Of note, serum calcium levels should be corrected for concurrent hypoalbuminemia and any hypomagnesemia should be medically corrected.

Patients who develop hypocalcemia should be discharged with calcium and vitamin D supplementation and if necessary calcitriol supplementation. After a few months, weaning from the calcium supplementation can be considered.

Injury to the recurrent laryngeal nerve

Injury to the recurrent laryngeal nerve (RLN) can yield vocal fold paresis or paralysis. The implementation of nerve monitoring has not been proven to lower this risk, but may provide prognostic value [19] . Studies show that identifying the RLN is associated with lower rates of injury.

Permanent RLN paralysis occurs in 1-2% of thyroidectomies in experienced hands. [44, 45] These cases may be underestimated, as not all patients undergo postoperative laryngeal evaluation. Should an injury occur, the patient usually presents with postoperative persistent hoarseness. Patients may also describe dysphagia or aspiration with thin liquids. Patients who undergo total thyroidectomy are at risk for bilateral vocal fold paralysis, a devastating complication. This usually manifests in the immediate postoperative period with airway obstruction, biphasic stridor, or respiratory distress.

Patients with suspected recurrent laryngeal nerve injury should be evaluated with flexible laryngoscopy or videostroboscopy to confirm the position and movement of the vocal folds. Should they have aspiration or dysphagia symptoms, they should be evaluated by a speech language pathologist. Patients with suspected bilateral vocal fold paralysis may require urgent and definitive airway management with a tracheotomy.

Permanent corrective procedures for vocal fold paralysis are not entertained until 9-12 months have passed. At this point, any persistent injury may be considered permanent.

Injury to the superior laryngeal nerve

The superior laryngeal nerve has both an internal and external branch. The internal branch provides sensory innervation to the larynx, while the external branch innervates the cricothyroid muscle. This posterior laryngeal muscle assists with lengthening of the vocal fold. Estimates of this complication vary, and are likely underestimated.

Often this injury is relatively asymptomatic. Patients may occasionally experience hoarseness or vocal fatigue. Voice professionals, however, can be significantly affected by this injury, as it affects the ability to produce higher-pitched sounds and thus may affect a singer’s upper register.

This injury too may be evaluated videostroboscopy, as well as laryngeal EMG. Some slight bowing of the affected vocal cord may be present, and the affected vocal cord may be lower than the normal cord. Additionally, EMG shows a deficit in the cricothyroid muscle.

Neck hematoma

A rare but dangerous complication of thyroidectomy, neck hematomas can form secondary to inadequate hemostasis or a coagulopathy. Incidence of this complication is approximately 1%, but its occurrence can lead to asphyxiation and airway compromise. [46] When identified on physical examination, the patient must be taken back to the operating room for exploration and achieving hemostasis. If the patient is in respiratory distress, the surgical wound should be opened and the hematoma evacuated immediately (even at the bedside) and then the patient should be taken to the operating room.

Infection

The rates of infection after thyroidectomy have significantly decreased with improvements in technology and aseptic technique and are currently estimated between 1-2%. [46]

The usual presentation is a superficial cellulitis with warmth, erythema, and tenderness surrounding the surgical incision. If fluctuance is present, a superficial abscess may also be present. Other signs of infection, such as fever and leukocytosis, without an overlying cellulitis, may point to a deep space neck infection or abscess.

CT imaging can be helpful in evaluating the deep spaces of the neck. Abscess needs to be drained, and the aspirate should be sent for cultures. Patients with a superficial cellulitis need to be on antibiotics that cover gram-positive organisms, while those with abscesses should be placed on broad-spectrum antibiotics until cultures yield specific bacteria.

Thyrotoxic storm

One of the contraindications for thyroidectomy is a patient with untreated or uncontrolled Graves disease or hyperthyroidism. One of the rarer complications from thyroid surgery is precipitation of a thyroid storm, which can occur intraoperatively or postoperatively. It is thought to occur secondary to thyroid gland manipulation in the operating room in patients with hyperthyroidism. Manifestations include tachycardia, hyperthermia, cardiac arrhythmias, and increased sympathetic output. Awake patients also present with nausea and altered mental status. If untreated, it may precipitate coma and death.

Intraoperatively, if signs of a thyrotoxic storm develop, the case needs to be halted and the patient needs to be medically managed to reduce sympathetic output. Cooling blankets, beta-blockers, PTU, and iodine should be administered.

Postoperatively, the patient may still have signs of thyrotoxicosis and should be continued on preventative medication. Medications can be weaned as thyroid hormone levels decrease.

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