Retrospective Analysis of Sequential Changes in Serum Intact Parathyroid Hormone Levels During Conventional Parathyroid Exploration

Background: The purpose of this study was to assess sequential changes in serum parathyroid hormone (PTH) levels during conventional parathyroidectomy.

Methods: Sera were collected before and 10 minutes after resection of each parathyroid tumor from 112 consecutive patients and assayed postoperatively within 48 hours for PTH.

Results: PTH reductions corroborated cures for 94 of 112 cases (84%), including 70 of 71 patients with solitary adenomas (SAs). However, there were 15 false positives (13%), in which PTH decreased more than 50% within 10 minutes of resection of 1 parathyroid tumor while additional parathyroid tumors remained in situ (1 of 71 SAs, 4 of 6 double adenomas, 7 of 15 primary hyperplasias, and 3 of 17 tertiary hyperplasias). There were 3 false negatives (3%), with PTH unchanged, even though postoperative PTH and calcium values confirmed cure (1 SA, 1 primary hyperplasia, and 1 tertiary hyperplasia). There were only 2 of 112 failed explorations (1.8%), which would not have been avoided by PTH monitoring because both subsequently were found to have mediastinal parathyroid adenomas.

Conclusions: We conclude that intraoperative PTH changes corroborated outcome in SA but may under-estimate the extent of resection required in parathyroid hyperplasia.