Use of intraoperative parathyroid hormone measurement does not improve success of bilateral neck exploration for hyperparathyroidism

HYPOTHESIS: Use of intraoperative measurement of intact parathyroid hormone (iPTH) to confirm complete excision of hyperfunctioning parathyroid tissue does not improve overall operative success rates. DESIGN: Case series of patients undergoing parathyroidectomy with or without intraoperative iPTH measurement. SETTING: University teaching hospital. PATIENTS AND INTERVENTIONS: Fifty patients undergoing parathyroidectomy before our institution of intraoperative iPTH sampling in March 1999 (group 1) were compared with 50 patients undergoing parathyroidectomy after this technique was adopted (group 2). Overall, 100 patients underwent operation between December 1996 and May 2000. Serum calcium and iPTH levels were measured at 1- and 3-month intervals. Intraoperative frozen sections and operative times were also analyzed. RESULTS: Mean preoperative calcium levels were 2.85 and 2.82 mmol/L (11.4 and 11.3 mg/dL) in groups 1 and 2, respectively. One-month postoperative calcium values were identical in both groups at 2.35 mmol/L (9.4 mg/dL) (group 1 SD = 0.18 [0.74], group 2 SD = 0.20 [0.82]). At 1 month, all but 1 patient in group 1 had normalized calcium values (2% failure rate), while 3 patients in group 2 (6%) remained hypercalcemic. All 3 patients in group 2 had intraoperative iPTH levels that returned to normal. There was a significant difference in the number of intraoperative frozen sections between groups, with a mean (SD) of 3.4 (1.7) in group 1 and 2.0 (1.6) in group 2 (P<.01). There was no significant difference in operative times between groups. CONCLUSIONS: Use of intraoperative iPTH sampling did not significantly affect the overall success of parathyroidectomy, as determined by postoperative normocalcemia. There was, however, a significant decrease in the number of frozen sections sent at operation.