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Thyroidectomy as a surgical procedure has a long history. Wilhelm Fabricius performed the first-recorded thyroidectomy in 1646.1 Unfortunately, the patient didn't survive and Fabricius was sent to prison. While the patient's cause of death isn't recorded, it's reasonable to assume that death could have been caused by any number of conditions that existed at that time. Lack of knowledge about the function of the thyroid and parathyroid glands could have accounted for the patient's death, as well as hemorrhage and infection.
 | Figure. No caption available. |
Surgical technique, antisepsis and anesthesia did improve with time, but the mortality for thyroidectomy was still very high through the mid-19th century. In 1883, one surgeon reported patient mortality at 40%. By the late 19th century, Theodore Kocher is credited with having identified the need to preserve the parathyroid glands.2 Kocher performed over 5,000 successful thyroidectomies during his career, and experience taught him that subtotal thyroidectomy resulted in fewer post-op complications and deaths.
The basics
The thyroid gland is located in the anterior middle portion of the neck just below the larynx, and is bordered by the carotid sheath on each side. The thyroid is commonly described as being shaped like a butterfly (see Location of the thyroid gland). It has a very high blood flow from the inferior and superior thyroid arteries.
The thyroid is one of the endocrine glands, meaning it secretes hormones that regulate bodily functions. Endocrine glands secrete hormones directly into the blood system rather than through a duct. Thyroxine (T4) and triiodothyronine (T3) are secreted by the thyroid gland. These thyroid hormones regulate several metabolic functions in the body, including growth and development, carbohydrate and lipid metabolism, as well as stimulate oxygen consumption by the cells.1 With the exception of the brain, spleen, uterus, and testes, the metabolic rate of all other cells in the body depends on adequate production and release of thyroid hormone (see Normal thyroid hormone production). Alterations in thyroid function impact cellular metabolism and neurologic, gastrointestinal, and cardiovascular function. If the gland produces too much hormone, the body goes into a hypermetabolic state. Too little, and bodily functions slow down.
The thyroid is innervated by the superior laryngeal nerves and the recurrent laryngeal nerves. These nerves contribute to the sensation and functioning of the larynx, the muscles that tense the vocal cords, and motor function of the muscles that alter the tension and length of the vocal cords.3 Disruption in the function of these nerves, therefore, affect swallowing and speech.
On either side of the thyroid are the parathyroid glands, which regulate calcium and phosphorous levels. The body requires a delicate calcium balance to be maintained for proper function of the nervous and muscular systems, as well as maintenance of the skeletal structure. Because of their proximity to the thyroid, the surgeon will carefully dissect the gland during surgery to prevent damage to the laryngeal nerves and prevent accidental removal of the parathyroid glands.
 | Figure. Location of the thyroid gland |
Indications for surgery
In the United States, more than 80,000 thyroidectomies are performed each year.4 Thyroid cancer is the most rapidly increasing cancer in women and is the seventh most common cancer in this population.5 Thyroid malignancies are more discreet than benign thyroid disease. A thyroid nodule may be found by the patient or is felt at the time of a routine physical exam. There are usually no symptoms of thyroid cancer except the nodule.
A thyroidectomy is most commonly performed to remove a malignancy, but is also performed for benign conditions such as goiters or Graves' disease. A goiter, which is an abnormal enlargement of the thyroid, may grow large enough to interfere with the airway or cause difficulty swallowing. Other indications of thyroid disease include hoarseness and a noticeable increase in neck size. A goiter may occasionally be large enough to extend into the substernal or thoracic area. This requires opening the chest for removal of the entire goiter. If the chest will be opened, thoracic instruments must be available in addition to thyroidectomy instruments.6
Graves' disease is another condition that causes enlargement of the thyroid gland. Graves' disease is a type of hyperthyroidism, or excess circulating levels of thyroid hormone.3 The excess levels of thyroid hormone produce a hypermetabolic state characterized by rapid heart rate, unintentional weight loss, sleeplessness, and anxiety. This hypermetabolic state increases consumption of oxygen and nutrients. Increases in metabolism cause tachycardia, so the patient may be placed on a beta-adrenergic blocker or other cardiac medication before surgery to control heart rate. Graves' disease is usually treated medically with either anti-thyroid drugs or with radiation to ablate the thyroid. However, if the disease fails to respond to medical treatment, surgery may be required.
Preparing the patient for surgery
Since thyroid disease generally develops over a period of time, thyroidectomy is rarely done emergently. If an emergent thyroidectomy is performed, it's usually done because an enlarged thyroid compromises the patient's airway and presents an immediate danger to the patient.5 Diagnosis of thyroid disease is based on results of lab work and ultrasound or computed tomography (CT) scans. If there's a nodule present, a fine-needle biopsy is often part of the diagnostic process. This provides information on the presence or absence of a malignancy.
While it's possible to remove the thyroid under local anesthetics, a thyroidectomy is usually performed under general anesthesia. Therefore, the patient will be instructed not to eat or drink on the day of surgery. Along with routine preparation of the patient, education and support are important in getting the patient ready for surgery.
 | Figure. Normal thyroid hormone production |
The location of the incision is visible and can often be the cause of anxiety and body image disturbance to the patient.3 Preoperatively, the nurse can address this with the patient and reassure her that the scar will most likely fade to only a thin line that is usually barely visible.
The preoperative nursing assessment should include an assessment of voice and facial movements so that a comparison can be made after surgery to assess for postoperative complications.1 This preoperative assessment should be documented to provide information to the post-op caregivers.
Patient teaching should include information about pain, availability of pain medication postoperatively, and wound care. It's also important to discuss the symptoms of hypocalcemia with the patient. The patient should be instructed to notify the surgeon immediately if she notes any numbness or tingling of the lips and hands after discharge.
Surgery
The extent of a thyroidectomy depends on the reason for surgery. The procedure may be scheduled as a partial or subtotal thyroidectomy if only one lobe of the thyroid is involved in the disease process. If disease is present throughout the entire thyroid, a complete thyroidectomy, or removal of the entire thyroid gland, is the procedure of choice. Occasionally, after a patient has undergone a partial thyroidectomy, final pathology reports will indicate that a tumor has extended farther than the initial resection and the patient has to return to the OR for complete removal of the thyroid.3 No matter how extensive the planned surgery, basic intraoperative care is the same.
The patient will be in a supine position on the table, with arms tucked. To help provide maximum exposure of the surgical site, there's usually a small shoulder roll placed under the patient's neck. With the neck held in extension by the shoulder roll, more of the operative field is visible to the surgeon. The surgeon will usually stand on the opposite side from the lesion at the beginning of the case.7 He may also ask for a headlight to help illuminate the relatively small operative site.6
Given that brachial plexus and ulnar nerve injuries are among the most commonly reported postoperative injuries, extra care should be taken to make sure the arms are well padded and properly positioned. The patient's arms should be in a neutral position with the palms facing the body and the fingers straight. If a sheet is used to hold the arms in place during surgery, it should be tucked under the mattress, and not under the patient to prevent the arms from "drooping" and sustaining injuries to the ulnar or radial nerves.8
The entire neck, from chin to shoulders, is prepped with an antiseptic solution, usually either povidone-iodine or chlorhexidine. The prep solution shouldn't be allowed to pool. Towels should be placed on either side of the patient's neck to absorb excess prep solution and then removed before the patient is draped.
It's important to note that the prep solution must be completely dry before surgery. Prep solutions are notoriously flammable and may increase the possibility of fire when the electrosurgical unit (ESU) is activated. It's also prudent to remember that the majority of fires in the OR involve head and neck procedures. The combination of an oxygen-enriched environment, flammable drapes and materials, and the high temperatures of the ESU pencil create a "fire triangle" that can be dangerous.9
The surgeon will determine the location of the incision based on the patient's body habitus and neck size as well as the reason for surgery. If the patient has a small neck, a small tumor, or she can extend her neck without limitations, the incision will be smaller. The incision will be made in a natural crease in the neck for a better cosmetic effect.6
It's common for the surgeon to use an ultrasonic scalpel to achieve hemostasis during a thyroidectomy procedure. Because ultrasonic energy is used instead of heat to cut and coagulate tissue, there is theoretically less chance of thermal damage to surrounding structures than if an ESU is used. Studies have shown that the use of a harmonic scalpel decreases operating time, but there have been no definitive studies that indicate any reduction of post-op complications.10
An intraoperative concern that the surgical team should be aware of is the occurrence of thyrotoxic crisis, or thyroid storm. Thyroid storm is an acute reaction to the sudden release of thyroid hormones into the circulatory system.11 Thyrotoxic crisis can occur for a variety of reasons. Intraoperatively, one possible cause can be manipulation of the gland itself. Thyroid storm is manifested by tachycardia, fever, dehydration, heart failure, and shock. While the clinical presentation during surgery may be similar to malignant hyperthermia, it can be differentiated by the anesthesia provider's close observation of end-tidal CO2.11
Due primarily to the proximity of the parathyroid glands to the thyroid, there's also a potential risk of unintentional removal or injury of the parathyroids. Approximately 20% to 40% of patients will develop mild, transient hypocalcemia postoperatively from injury to the parathyroids.3
Monitoring calcium levels postoperatively may lengthen the patient's length of stay in the hospital by several days.12 The surgeon may choose to monitor parathyroid hormone levels intraoperatively to detect parathyroid injury and determine whether the patient may have sustained an injury to the parathyroids. This aids in determining whether the patient is a candidate for discharge within 24 hours following surgery.
Intraoperative parathyroid hormone monitoring requires blood samples to be drawn at specified intervals during the procedure. Blood is drawn immediately after induction, and at 5-, 10-, and 20-minute intervals following removal of the thyroid gland. Accurately labeling the tubes and sending the blood promptly to the lab are important as well. As results are obtained, they should be reported to the surgeon immediately and recorded in the patient record.
During thyroid surgery, there's also a possibility of injury to the nerves near the thyroid gland. Intraoperative nerve monitoring (IONM) may be used to identify and protect the nerves. If the surgeon requests IONM at the time of induction, the patient will be intubated with an electrode-bearing endotracheal tube, which is connected to a monitoring device. The recording wires of the tube must be in contact with the vocal cords. During the procedure, a nerve stimulator wand is used to stimulate the nerve and produce vocal cord contractions. Contraction of the vocal cord confirms that the nerve is correctly identified.12
After the thyroid is removed, the surgeon will inspect it closely to see if the parathyroids may have been inadvertently removed as well. If there is suspicion a parathyroid gland is removed, a small biopsy sample of the gland will be sent to pathology to verify that it's indeed a parathyroid, and the parathyroid tissue may be autotransplanted immediately or sent to a tissue bank to be cryopreserved and reimplanted at a later date if necessary.7 If parathyroid tissue is reimplanted, it's usually placed in the arm or an area with a good blood supply.
All forms of thyroid cancer have the potential to metastasize to the regional lymph nodes in the neck.7 If surgery is being done for a thyroid malignancy, lymph node dissection or sampling may also be part of the procedure. A second set up, or a basin to quarantine instruments that come in contact with malignant tissue, is required.
Before wound closure, the surgeon may place a drain in the wound bed. As noted earlier, the thyroid is highly vascularized, and there is potential for developing a hematoma postoperatively. The drain is placed to monitor postoperative bleeding and help prevent hematoma or seroma formation.2
Traditionally, the thyroidectomy incision is closed with a subcuticular stitch. But it's now common for the surgeon to use a topical skin adhesive for skin closure. Either of these methods is preferable to stapling, which produces a "railroad track" scar that is less cosmetically pleasing to the patient.14
Endoscopic thyroidectomy
As noted earlier, concerns about the size and location of the surgical scar create anxiety for many patients. Advances in endoscopic technology are making endoscopic thyroid surgery more common.10 Because the ports for endoscopic procedures are placed at sites away from the neck, there is no visible scar.
Endoscopic thyroidectomy can be performed using either a video-assisted or totally endoscopic technique. In video-assisted neck surgery, ports are placed at the anterior chest and subclavian sites. One drawback to this approach is that the skin on the anterior chest has a high incidence of keloid scar formation.14
If the procedure is endoscopic, there is CO2 insufflation with the ports placed in the axilla. While this procedure places the scars in less visible locations, the surgery is more ergonomically difficult because of the distance of the ports from the surgical site.15 In addition to the cosmetic result, there are some other benefits to endoscopic thyroidectomy. As with most minimal access procedures, patients report less post-op pain, thereby require less pain medication, all of which can lead to a more rapid recovery.10 However, the tumor size or size of the thyroid gland may limit the patient's suitability for endoscopic thyroid surgery.
Placement of ports required for endoscopic thyroidectomy and insufflation with CO2 place the patient at risk for some complications that aren't present with a traditional thyroidectomy. Chief among these are peristernal bruising and subcutaneous emphysema. However, the cosmetic results make minimally invasive thyroidectomy a good option for people who are appropriate candidates.14
Risks and complications
Postoperative complications from thyroidectomy are rare but can be life threatening.6 Postoperative hematoma formation is common due to the thyroid's rich blood supply.3 As with all post-op patients, the nurse will observe for classic signs of bleeding like hypotension and tachycardia. It's essential the patient also be observed for increasing neck size and difficulty breathing. A rapidly developing hematoma can quickly compromise the patient's airway.
The nurse should also be diligent about checking the dressing for blood; both anterior and posterior neck dressings should be observed.3 Any sign of excess bleeding must be reported to the surgeon immediately. It's also possible the incision will be closed with a topical skin adhesive and may not be covered with a dressing, therefore, bleeding or swelling are immediately evident if this occurs. Some hospitals require a tracheotomy set be at the patient's bedside during the immediate post-op period.
 | Figure. Anterior and medial retraction of the thyroid showing recurrent laryngeal nerve and parathyroid gland anatomy |
Laryngeal nerve damage is one of the most common complications of thyroidectomy surgery and may occur due to clamping, compressing, stretching, or severing the nerve during surgery.3,12 Even with diligent visual inspection, a nerve injury resulting in immediate transient post-op paralysis occurs in 4% to 8% of thyroidectomy patients, and permanent paralysis in 1%.3 (See Anterior and medial retraction of the thyroid showing recurrent laryngeal nerve and parathyroid gland anatomy.) Because these disease processes make the recurrent laryngeal nerve more difficult to identify, the risk of nerve injury is higher if the thyroidectomy is performed for cancer, substernal goiter, Graves' disease, or reoperation.13 Injury to the recurrent laryngeal nerve could result in airway obstruction, characterized by inspiratory stridor, dyspnea, and tachypnea. Recurrent laryngeal nerve injury is usually recognized when the patient is extubated, but it may not become noticeable for several hours after surgery.2 If the injury occurs to the superior laryngeal nerve, the patient may lose protective reflexes and is at risk for aspiration. In either case, the nurse should be prepared for emergent airway maintenance, which may include reintubation or emergency tracheotomy.
The tone and pitch of the patient's voice and swallowing ability should be assessed every 1 to 2 hours postoperatively to detect signs of nerve injury. As the patient regains consciousness, asking her to answer questions provides an opportunity to assess voice quality. No liquids or ice chips should be given to the patient without first assessing that the reflexes are intact and there's no difficulty swallowing.
Hypocalcemia from inadvertent removal or injury to the parathyroid glands may develop approximately 12 to 36 hours after surgery.3 Symptoms of mild hypocalcemia include circumoral numbness, paresthesias of the distal extremities, muscle cramps, irritability, and prolongation of the QT interval on ECG. Severe manifestations of hypocalcemia include neuromuscular irritability associated with tetany.16
If hypocalcemia is suspected, the nurse should assess for Chvostek's sign (contraction of the facial muscles produced by tapping the facial nerve anterior to the ear). (See Eliciting Chvostek's sign.) If hypocalcemia is severe, the Trousseau's sign (carpal spasm produced by pressure of the nerves in the upper arm during inflation of a blood pressure cuff for 3 to 5 minutes) may be evident.16
 | Figure. Eliciting Chvostek's sign |
For hypocalcemia that is relatively mild, treatment requires only oral calcium and vitamin D supplements. If hypocalcemia is severe or symptomatic, it's treated with I.V. calcium gluconate. Serum calcium levels will usually be checked the evening of and morning after surgery to determine if any degree of hypoparathyroidism exists. Fewins, Simpson, and Miller2 note that the presence of a below normal calcium level immediately after surgery doesn't always mean there's permanent injury to the parathyroids. There may be some degree of hypocalcemia simply from transient disruption of parathyroid function as a temporary effect of surgery. The postanesthesia care unit and post-op nurse should remain aware of the potential for complications and regularly assess the patient for their onset.
Striving for best outcomes
As with any operative procedure, preparation of the staff and patient are essential for the success of the operation. Surgeon preference cards must be updated and OR staff should be prepared and know when new equipment arrives, regardless of the reason for thyroidectomy. After all, the best possible outcome for the patient should be everyone's goal.
REFERENCES
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