Intraoperative monitoring of kinetic total serum calcium levels in primary hyperparathyroidism surgery.

BACKGROUND: In the setting of minimal approach Sestamibi-guided parathyroid surgery for primary hyperparathyroidism we evaluated if total serum calcium level monitoring is as valuable as intraoperative parathyroid hormone (iPTH) monitoring.

STUDY DESIGN: Prospective open single-blinded efficacy trial of two intraoperative diagnostic monitoring methods (iPTH and total serum calcium level) on a cohort of surgical patients. All patients (n = 35) were undergoing parathyroid surgery at the Department of General Surgery at B Cruces' Hospital, Vizcaya, Spain, between October 1999 and March 2001. Kinetics of serum levels of Ca and iPTH during surgery and time of prediction of cure for each method (measured in the clinic, admission, and intraoperatively, such as induction of anesthesia, and every 5 minutes after removal of adenoma) were analyzed.

RESULTS: Hypercalcemia and iPTH levels became corrected in 34 patients. Average serum calcium levels dropped from pathologic 11.07 +/- 0.41 mg/dL (mean +/- standard deviation) to normal values 9.7 +/- 0.82 mg/dL during the first intraoperative determination (minute 5), but mean iPTH decreased from pathologic (192 +/- 98 pg/mL) to normal values (39.93 +/- 25.12 pg/mL) during the third intraoperative determination (minute 15). Serum calcium level at 5 minutes after removal decreased by 100% in 34 patients, but iPTH only showed a similar drop during the third determination at 15 minutes. Frozen sections were conclusive for parathyroid tissue (20.56 +/- 10.3 minutes after removal).

CONCLUSIONS: Intraoperative measurement of total calcium level might be an easier and less expensive method than iPTH measurement in the prediction of cure during surgery for primary hyperparathyroidism resulting from adenoma.