The thyroid gland sits in the midline lower neck below the Adam’s apple (thyroid cartilage notch). It is shaped like a butterfly with a left and right lobe and a variable sized middle portion called the isthmus. The gland functions to release thyroid hormone which controls functioning of many cells of the body. Surgery is performed for several reasons including cancer, a nodule that is suspicious for cancer, a large nodule or gland that is causing symptoms of hoarseness, pain, or difficulty swallowing, or for a hyperactive gland (hyperthyroidism). Most of the time a single side is removed and occasionally the entire gland is removed. Typically when one side is removed there is an overnight stay. The body actually only needs a small portion of the gland to remain euthyroid (normal thyroid function).
Thyroid nodules are more common in females. Increased risk factors for thyroid cancer for a nodule include older age, male sex, larger size of the nodule, family history of thyroid cancer, and prior radiation exposure to the neck area.
Work-up for thyroid problems can include the following:
- Blood tests – at least a TSH or Thyroid Stimulating Hormone to determine if the gland is underactive (hypothyroid), normal functioning (euthyroid) of overactive (hyperthyroid).
- Ultrasound to determine the size of the gland and presence of any nodules
- Needle biopsy if a large enough nodule is present to rule out thyroid cancer. This is often performed under ultrasound guidance by the radiologist or endocrinologist.
- Thyroid scan – a nuclear medicine scan to help determine the function of the gland, usually ordered of blood tests revel an overactive gland
Sometimes during surgery a preliminary diagnosis is made by the pathologist (frozen section result). If the surgery is being performed to rule out thyroid cancer and the pathologist confirms cancer, then a total thyroidectomy may be performed. However, most of the time a preliminary diagnosis cannot be made. The final decision as to whether further surgery to remove the other side of the gland is needed is made only after several days once final pathology is back. Statistically this does not happen frequently.
Two specific risks of thyroid surgery include injury to the recurrent laryngeal nerve and postoperative low calcium levels (hypocalcemia). The recurrent laryngeal nerve is the nerve that controls the movement of the vocal cord and there is one on the left and right side. The nerve leaves the bottom of the brain and down the neck into the chest, and then loops back upwards to the vocal cord. The nerve then runs directly underneath the thyroid gland.
The nerve is identified at the beginning of surgery to prevent injury as best as possible. Injury can range from swelling of the nerve to worst case scenario of permanent damage. Postoperatively it is not uncommon to experience some degree of hoarseness secondary to swelling around the nerve from surgery. There is no way to predict which patients will have what degree of hoarseness after surgery.
Hoarseness could range from a few days to even several months or longer. However, as long as the nerve is physically intact, complete function will return. Surgery on both sides of the neck (total thyroidectomy) poses an increased risk, because if there is injury to the nerve on both sides, the patient will experience difficulty breathing, typically within 24 hours.
The second specific risk of surgery is injury to the parathyroid glands. There are typically four small glands that sit on the undersurface of the thyroid gland at each corner. The parathyroid glands control the body’s calcium levels. Again there is a range of possible injuries from temporary injury to permanent injury. If all four glands are injured, the body’s calcium level may decrease quickly leading to symptoms of numbness and tingling around the mouth and extremities to chest pain, shortness of breath, and shakiness.
The body really only needs a portion of one of the glands to be able to maintain normal calcium levels. With thyroid surgery specifically, if only one side is removed, there is almost no risk to calcium problems because there should be two untouched glands on the opposite side, so it really is not even an issue. With partial or hemithyroidectomy, calcium levels are not routinely checked in the hospital after surgery. With total thyroidectomy or surgery on both sides, then the potential risk is more pronounced and after surgery serial blood calcium levels will be drawn in the hospital.
Parathyroid surgery is most often performed for hypercalcemia (elevated blood calcium levels). A parathyroid adenoma (overactive single gland) is the most common reason (over 90%) and is usually diagnosed before surgery with a nuclear medicine parathyroid scan which will localize which of the four glands is over active and blood tests showing an elevated calcium level and elevated parathyroid hormone level. Other possible reasons include hyperplasia (all 4 glands are overactive) and cancer (extremely rare).
Surgical risks are similar to thyroid surgery with a few minor differences. There is typically less risk to injury to the recurrent laryngeal nerve because there is less dissection performed. Calcium levels will always be checked in the hospital after surgery until they stabilize. Blood calcium levels will always fall after surgery to some degree. Typical hospital stay is one night.
For either surgery, the incision is horizontal across the neck in a natural skin crease if one exists. A surgical drain is placed to collect any fluid that accumulates under the skin after surgery and is usually removed the following morning. Most patients do not require any oral pain medications other than Tylenol after the first day and resume a normal diet the day after surgery. Sutures are removed one week after surgery. One may feel tightness of the neck especially when swallowing which resolves within a few weeks.