Can Parathormon Levels after Ipsilateral Lobectomy Predict Postoperative Hypocalcemia in Patients Undergoing Total Thyroidectomy?

Abstract

The purpose of this study was to investigate the relationship between the serum parathormone (PTH) levels measured after completion of hemithyroidectomy on the first side during total thyroidectomy and the postoperative hypocalcemia. The patients were divided into two groups, as those who demonstrated a decrease in PTH levels measured after completion of hemithyroidectomy of the first side (Group 1, n = 43) and those who did not demonstrate a decrease in PTH levels (Group 2, n = 24). The serum PTH levels were measured just before the incision (PTH_i), when the hemithyroidectomy stage had been completed (PTH_ht), at the end of the operation (PTH_tt), and at the postoperative 24th hour (PTH_24hr). The serum total calcium (Ca²¹) levels were also measured. The median percentage differences in PTH_tt levels based on basal PTH_i levels of Groups 1 and 2 were -60.6 and -15.7 per cent, respectively, P = 0.001. The frequency of postoperative biochemical hypocalcemia was higher in Group 1, P < 0.05. It was determined that a 10 per cent or higher decrease in PTH_ht levels in Group 1 could predict biochemical hypocalcemia at the postoperative 24th hour. In conclusions, postoperative hypocalcemia is seen more frequent in patients with a decrease of PTH_ht during total thyroidectomy. A decrease of 10 per cent in PTH_ht levels measured after ipsilateral lobectomy and a 62 per cent or higher decrease in PTH_tt levels measured in the end of the total thyroidectomy could be helpful for prediction of postoperative hypocalcemia in these patients.