The main cause of numbness in the hands after thyroid surgery is due to hypoparathyroidism. In a normal person, there are usually four parathyroid glands, which are tightly attached to the back of the thyroid gland, and its blood flow depends on the branches of the blood vessels of the thyroid gland to supply nutrients. During thyroid surgery, the blood vessels associated with the thyroid must be severed, which causes the blood supply to the parathyroid glands to be compromised, and hypoparathyroidism occurs, which may lead to symptoms of hand numbness. This condition needs to be relieved often with calcium or D supplements. Typically, it may lessen and disappear about two months after surgery as the blood supply recovers, and symptoms may be reduced with frequent calcium supplementation as well as treatment for hypoparathyroidism.