The parathyroid glands are tiny glands that secrete parathyroid hormone (PTH), which controls calcium metabolism. Most people have four of these glands located close to the thyroid gland in the neck. Sometimes, the glands can be in unusual or ectopic locations in the neck or chest.
Diseases of the Parathyroid Glands
This group of diseases is characterized by excess parathyroid hormone (PTH) secretion. Mild disease may be completely without symptoms, detectable only by laboratory testing. Common symptoms include kidney stones, bony aches and pains, osteoporosis and/or bony fractures, fatigue, constipation, thirst, and nocturia. Severe disease may manifest with profound dehydration and mental status changes.
The parathyroid gland(s) enlarge and produce excess PTH, in spite of normal to elevated calcium levels. In 85% of cases, only one gland is affected. In 15% of cases, more than one gland is abnormal (multiglandular disease). Only rarely is parathyroid cancer the cause. Indeed, the cause is unknown in most people; a small percentage will have inherited disease such as MEN1, MEN2A, or familial hyperparathyroidism.
The parathyroid glands enlarge and produce excess PTH, in response to an external stimulus, usually related to kidney insufficiency or failure. The calcium level is usually low or normal, although it may be elevated in some advanced cases. All four glands are affected, though some may be larger than other (asymmetric hyperplasia).
After correction of kidney insufficiency with a transplant, some parathyroid gland(s) fail to normalize and remain enlarged and producing excess PTH.
A lack of parathyroid hormone results in hypocalcemia, or low calcium levels. The symptoms are numbness and tingling around the mouth, fingers and toes, muscle spasms, and in severe cases – tetany. It can be treated with calcium and vitamin D. After surgery to the thyroid and parathyroid glands, hypoparathyroidism may be transient (recover within days to months), or infrequently, permanent.
A very rare cause of primary hyperparathyroidism. Typically, patients present with very high levels of PTH and calcium, and may have a lump.
This is surgery performed to remove overactive parathyroid gland(s). In the appropriate patient, minimally invasive parathyroidectomy (MIP) with preoperative imaging (sestamibi and/or ultrasound), and intraoperative PTH monitoring is our operation of choice. Locoregional anesthesia may be offered. A conventional four gland exploration may also be performed. Patients undergoing reoperative parathyroidectomy present a special challenge but will still have a successful operation most of the time.
Types of Parathyroidectomy
Conventional 4-gland parathyroid exploration
A small incision (2 to 3 inches) is made in the front of the neck and the muscles covering the thyroid gland are moved aside. All four parathyroid glands on both sides of the neck are identified. Only enlarged gland(s) are removed. A subtotal or 3 ½ gland parathyroidectomy removes all parathyroid glands except for part of one, which is either left in its original place, or reimplanted in the forearm or neck muscles.
Minimally invasive parathyroidectomy (MIP)
This procedure is possible only if preoperative imaging (sestamibi and/or ultrasound) identifies a single abnormal parathyroid gland in the neck. A small incision (1 to 2 inches) is made in the front of the neck. Minimal dissection is done to expose and remove the gland. The surgery can be performed under locoregional anesthesia, if desired. Intraoperative PTH monitoring is used to confirm removal of all hyperfunctioning parathyroid tissue.
In patients who have failed initial parathyroidectomy or develop recurrent hyperparathyroidism, the approach is to perform additional imaging studies to identify the abnormal gland’s location. These studies may include repeat sestamibi and ultrasound scans, CT, MRI, and selective venous sampling for PTH. After the gland is identified, a directed approach is used to remove it. The success rate achieved by experienced parathyroid surgeons is very good.
Locoregional anesthesia for parathyroidectomy
Minimally invasive parathyroidectomy may be performed under locoregional anesthesia. In this type of anesthesia, the sensory nerves to the neck are blocked by injecting local anesthesia on the side of the neck prior to the operation. The patient is awake but sedated and comfortable. They may feel some tugging and pulling, but should not feel any pain.