Parathyroidectomy is the surgical removal of one or more of the (usually) four parathyroid glands. This procedure is used to remove an adenoma or hyperplasia of these glands when they are producing excessive parathyroid hormone (PTH): hyperparathyroidism. The glands are usually four in number and located adjacent to the posterior surface of the thyroid gland, but their exact location is variable. When an elevated PTH level is found, a sestamibi scan or an ultrasound may be performed in order to confirm the presence and location of abnormal parathyroid tissue. Indications The main indication for parathyroidectomy is primary hyperparathyroidism, a condition in which one or more of the parathyroid glands produce excessive parathyroid hormone. Not all cases of primary hyperparathyroidism require surgery, but it is recommended if the condition causes significant symptoms or if it affects the kidneys (nephrocalcinosis) or bone health (osteoporosis), and also in people under 50 even if they do not have symptoms. It is not always possible to anticipate if a parathyroid tumor is malignant (i.e. capable of invading other tissues or spreading elsewhere). Any suspicion of parathyroid carcinoma is therefore also an indication for surgery. Parathyroidectomy may also be required in secondary hyperparathyroidism. This situation arises mainly in people with severe chronic kidney disease in which the parathyroid glands are overactive to compensate for the low calcium and vitamin D levels often present in CKD. In many cases, the parathyroid hormone production improves when these abnormalities are treated with medication. A small proportion, however, have persistently raised hormone levels six months after treatment has started, thought to be autonomous production of hormone by the glands and loss of feedback mechanisms. In this situation surgical parathyroidectomy may be required, especially if calcium and phosphate levels remain elevated, there is calcium deposition in the wall of blood vessels (calciphylaxis in severe cases) or there is worsening bone disease. In people on dialysis, parathyroidectomy can improve their survival. It does appear that the procedure may be underused. Procedure The operation requires a general anesthetic (unconscious and pain free) or a local anesthetic (pain free). The surgeon makes an incision around an inch long in the neck just under the larynx (Adam's apple), and locates the offending parathyroid glands. Preoperative testing using sestamibi scanning can help identify the location of glands. It can also be used to limit the extent of surgical exploration when used in conjunction with intraoperative PTH