Parathyroidectomy

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.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.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 hormone monitoring. The particular problem or disease process will determine how many of the parathyroid glands are removed. Some parathyroid tissue must be left in place to help prevent hypoparathyroidism.While mild hypocalcemia is common after partial parathyroidectomy, some people experience persistently prolonged low calcium levels. This is called hungry bone syndrome. Despite the reactivation of unresected parathyroid glands producing normal to elevated levels of PTH, serum calcium continues to be low. The balance between calcium influx and efflux within the bone continues to be disrupted, favoring the former. The bone is said to be 'hungry' as it consumes minerals without regard to PTH; calcium, magnesium, and phosphate continue to be deposited into the bones, resulting into hypocalcemia, hypomagnesemia, and hypophosphatemia. Prolonged calcium supplementation may be required. Hungry bone syndrome is particularly common in people who are on long-term regular dialysis.