There are normally 4 parathyroid glands located near or attached to the back surface of the thyroid. Each gland is usually about the size of a grain of rice (about 3-5 millimeters in diameter and around 30 - 60 milligrams in weight). Although the thyroid and parathyroid glands are physically near to each other and are both part of your body's endocrine system, their functions are not related. Parathyroid glands secrete a hormone, which controls your blood calcium level. Calcium is important for muscle and nerve function.

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Parathyroid glands make parathyroid hormone (PTH) to regulate the level of calcium in the blood. Other cells in the body, especially cells of the bones, kidneys, and small intestine, respond to PTH by increasing the calcium levels in the blood. Under normal conditions, this control is quite accurate. If one or more parathyroid glands enlarge and become overactive, your blood calcium level may increase. This condition is called primary hyperparathyroidism. These tumors are nearly always benign, but they may cause other problems such as kidney stones, mood changes or depression, or weakened or painful bones. The most common treatment for primary hyperparathyroidism is surgical removal of the abnormal gland or glands. Surgery can provide a permanent cure for this condition.

As with a thyroid operation, a parathyroid operation takes place in the operating room under a general anesthetic. An incision is made along the collar line. The surgeon will move the thyroid gland to one side, then the other, to allow inspection of the parathyroid glands, which are located behind or to the side of the thyroid, deep within the neck. The surgeon will remove one or more of the parathyroids, depending on the specific disorder. The muscles are then repaired and the skin incision is closed with sutures that will either absorb or be removed soon after your operation.

Every attempt is made to protect the nerves serving your vocal cords and the remaining parathyroid glands so they will function normally soon after your surgery. It is not uncommon to have a low calcium level after a successful surgery. That situation is nearly always temporary and normal function is restored in over 98% of people in just a few weeks.

You may have read about minimally invasive, or "keyhole," surgery for this problem. This is sometimes feasible and is being investigated here in a very careful fashion. Although it is being performed in some areas of the world, there are concerns about the possibility of more complications and a lower success rate with this type of procedure. Therefore, it is not yet widely accepted as a standard operation. If you think you would like to be a candidate for this type of operation within a clinical trial, ask your surgeon to discuss this with you.