PTH and Hypocalcemia: Postoperative low levels of parathyroid hormone (PTH) and consequent hypocalcemia may be associated with an injury to parathyroid glands because of incidental removal of one or more glands, or to a compromised blood supply as a result of their dissection [3,12], and this risk may be further increased in patients undergoing total thyroidectomy and a neck dissection [3,9,11,14,15].