Hormone, Relationships of Parathyroid Gamma Counts, and Adenoma Mass in Minimally Invasive Parathyroidectomy

Objective. To better understand relationships of parathyroid hormone (PTH) production, adenoma gamma counts, and adenoma mass in patients undergoing minimally radioguided invasive parathyroidectomy for primary hyperparathyroidism from single-gland disease. Study Design. A prospective review of 104 patients operated on by a single surgeon. Setting. University tertiary hospital. Subjects. Adults who have primary hyperparathyroidism due to a single gland. Results. There were 23 men and 81 women with an average age of 63 years. The mean (SD) adenoma mass was 0.78 (0.69) g (median, 0.57 g). The mean (SD) percent of background for the adenoma was 120.2 (90.5). Preoperative PTH and percent of background gamma count of the adenoma showed a likely correlation with a Spearman rho value of 0.2039 and a P value of .037. There were significant correlations between both percent of background of the adenoma and adenoma mass (Spearman rho = 0.4991 and P < .0001). Preoperative PTH and adenoma mass also showed a significant positive correlation (Spearman rho = 0.308 and P = .002). Conclusion. There exist correlations between gland mass, radioactivity, and PTH level. Adenoma radiation counts do not appear to be a proxy for changes in PTH levels measured during surgery as has been reported. Intraoperative PTH has been shown by others not to be necessary when doing radioguided parathyroid surgery if the Norman rule is observed. However, a radioguided technique and intraoperative PTH can provide complementary information in making an assessment of completion of parathyroid procedures.