Adenoma weight: a predictor of transient hypocalcemia after parathyroidectomy.

To evaluate the relationship of parathyroid adenoma weight to perioperative serum calcium levels, 51 selected patients with pathologically confirmed single adenomas and minimal biopsy at operation were reviewed. Three age- and sex-matched groups were established according to adenoma weight. Compared with Group 1 patients who had adenomas of less than 1 g, Group 3 patients with adenomas of more than 2 g demonstrated significantly higher preoperative serum parathyroid hormone and calcium levels, and significantly lower preoperative serum phosphate levels. Multiple regression analysis revealed a strong correlation between adenoma weight to preoperative parathyroid hormone and calcium levels (r = 0.63, p less than 0.001). These results suggest that larger adenomas may be associated with a more severe form of primary hyperparathyroidism. The incidence of transient postoperative hypocalcemia in the 51 patients who underwent adenoma excision was 37 percent. Permanent hypoparathyroidism did not develop in any of them. Compared with Group 1 patients, Group 3 patients demonstrated a higher incidence of postoperative transient hypocalcemia (69 percent versus 14 percent in Group 1, p less than 0.001) and significantly lower mean serum calcium levels on the third and fourth postoperative days. Increased adenoma weight may be a valuable aid in identifying those patients at risk for transient hypocalcemia after neck exploration.