PTH and Hypocalcemia: After surgery, a rapid shift of calcium from the bloodstream to bone occurs with a marked increase in bone remineralization, which is caused by abrupt removal of elevated PTH levels.[19,20,22] Bone biopsies showed extensive remineralization, implying active deposition of calcium and phosphate into the skeleton.[29] Mineralization of bone remodeling units may lead to hypocalcemia and hypophosphatemia until the new osteons are complete.