Unilateral and bilateral surgery for parathyroid disease

Preoperative calcium and parathyroid hormone values are poor predictors of gland volume and multigland disease in primary hyperparathyroidism: A review of 2,000 consecutive patients

OBJECTIVE

Calcium and parathyroid hormone (PTH) values are thought to have a linear relationship in patients with primary hyperparathyroidism and correlate with parathyroid gland size, with higher values predicting single-gland disease. In this modern series, these preoperative values are correlated with operative findings to determine their utility in predicting gland involvement at parathyroid exploration.

METHODS

Two thousand consecutive patients who underwent initial surgery for sporadic primary hyperparathyroidism from 2000 to 2014 were reviewed. All patients underwent a four-gland exploration. Relationships between preoperative calcium and PTH values with per patient total gland volume were examined and stratified by number of involved glands: single adenoma (SA), double adenoma (DA), and hyperplasia (H).

RESULTS

There were 1274 (64%) SA, 359 (18%) DA, and 367 (18%) H cases. There was poor correlation between preoperative calcium and PTH (R=0.37), and both correlated poorly with total gland volume (R<0.40). Subgroup analysis by the number of involved glands similarly showed poor correlation. Mean total gland volume was similar among all subgroups (SA=1.28, DA=1.43, H=1.27 cc, p=0.52), implying individual glands were smaller in multigland disease. SA was found in 53% of patients with calcium ≤10.5 mg/dL and 78% if ≥12 mg/dL (p<0.001).

CONCLUSION

This is the largest series correlating preoperative calcium and PTH values with operative findings of gland size and number of diseased glands. Although a lower calcium value predicts somewhat more multigland disease, the overall poor correlation should make the parathyroid surgeon aware that gland size and multigland disease cannot be predicted by preoperative laboratory testing.