Retrospective analysis of sequential changes in serum intact parathyroid hormone levels during conventional parathyroid exploration.

Abstract

The purpose of this study was to assess sequential changes in serum parathyroid hormone (PTH) levels during conventional parathyroidectomy. 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. 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. We conclude that intraoperative PTH changes corroborated outcome in SA but may under-estimate the extent of resection required in parathyroid hyperplasia.