A. A. Carr1, T. W. Yen1, D. B. Evans1, T. S. Wang1 1Medical College Of Wisconsin,Division Of Surgical Oncology,Milwaukee, WI, USA
Introduction:
During parathyroidectomy for primary hyperparathyroidism (pHPT), increases (“spikes”) in intraoperative parathyroid hormone (IOPTH) levels from the preoperative [baseline] PTH may occur due to manipulation of abnormal parathyroid gland(s) prior to resection. These IOPTH spikes may lead to longer operative times and/or more extensive neck exploration. The aim of this study was to determine if the extent of IOPTH increase may predict the presence of single gland disease (SGD).
Methods:
This is a retrospective review of a prospective parathyroid database of patients undergoing parathyroidectomy for sporadic pHPT from 1999 to 2013. Demographic and clinical data were collected from all patients who had an increase in IOPTH level from baseline drawn prior to induction of anesthesia to the time of first gland excision (T0) and the extent of the IOPTH spike was calculated. Patients were divided into 3 groups: Group 1 had no IOPTH spike at T0, Group 2 patients had a T0 spike of 1-3 times above the baseline PTH, and Group 3 had a T0 spike >3 times above the baseline PTH.
Results:
Of the 911 patients in the cohort, there were 645 (71%) patients in Group 1, 234 (26%) in Group 2, and 32 (3%) in Group 3. A single parathyroid adenoma was resected in 87%, 78% and 100% of patients in Groups 1, 2 and 3, respectively (Table). An IOPTH spike of >3 times above the baseline had a specificity and positive predictive value of 100% for predicting SGD. The median gland weight in Group 3 (920mg) was significantly larger than those in Groups 1 and 2 (440 and 460mg, respectively). At a median follow-up of 22 months (interquartile range 11-37 months) for the entire cohort, there was no difference in rates of persistent or recurrent disease between the three groups.
Conclusion:
IOPTH spikes occur in over 25% of patients undergoing parathyroidectomy for sporadic pHPT. Patients with IOPTH spikes >3 times above the BL PTH are more likely to have larger, single adenomas, whereas patients with IOPTH spikes of 1-3 times above the baseline more often have multi-gland disease. This suggests that in patients with significant elevation in IOPTH levels between the baseline and excision of a large parathyroid adenoma, no further surgical exploration is required prior to conclusion of the procedure.
