PTH and Hypocalcemia: PTH, Ca, and ALP were used as independent variables and the occurrence of hypocalcemia was used as a dependent variable to construct a mathematical prediction model: Logit (p) = 5.16568 + 0.00134 * PTH-3.44615 * CA+0.00136 * ALP.To increase the usefulness of this model, we generated a nomogram that shows scores corresponding to each risk factor and a total of all the risk factors, corresponding to the risk of postoperative hypocalcemia (Figure 1).