Validity and limits of intraoperative parathyroid hormone monitoring during minimally invasive parathyroidectomy: a 10-year experience

The availability of intraoperative intact parathyroid hormone monitoring allows the success of minimally invasive parathyroidectomy to be ensured during the operation. However, false-negative results leading to unnecessary explorations and difficulties in interpreting the data raise concern about the effectiveness of the method. Patients with primary hyperparathyroidism (pHPT) and one unequivocally enlarged parathyroid gland on preoperative ultrasound or Tc-99m-SestaMIBI scintigraphy underwent minimally invasive video-assisted parathyroidectomy according to the technique initially described by Miccoli. Intraoperatively, rapid electrochemiluminescence immunoassay was used to measure intact parathyroid hormone (iPTH) levels before the operation, after complete mobilization of the adenoma (preexcision value), and 5, 10, and 15 min after the excision. The operation was considered successful when more than a 50% decrease in preexcision iPTH levels and subsequent attainment of the normal range within 15 min were observed. Between November 1999 and November 2009, 235 (43%) of 546 patients with pHPT were eligible for a minimally invasive approach. Intraoperative iPTH monitoring showed 221 true-positive, 1 false-positive, 6 false-negative, and 7 true-negative results. This calculated to a sensitivity of 97% and a specificity of 88%. Despite the availability of high-resolution ultrasound and Tc-99m-SestaMIBI scintigraphy, the presence of multiple glandular disease cannot be ruled out completely. Although the authors observed six false-negative results, they believe that intraoperative iPTH monitoring represents a valuable asset for minimally invasive parathyroidectomy because it identifies sporadic hyperplasia.