Radioguided Parathyroidectomy Is Equally Effective for Both Adenomatous and Hyperplastic Glands

Abstract

Objective To determine the utility of radioguided parathyroidectomy for patients with hyperparathyroidism, we studied the properties of 180 resected, hyperfunctioning parathyroid glands. Summary and Background Data Radioguided resection of hyperfunctioning parathyroid glands has been shown to be technically feasible in patients with parathyroid adenomas. Radioguided excision may obviate the need for intraoperative frozen section because excised parathyroid adenomas uniformly have radionuclide ex vivo counts >20% of background. The feasibility and applicability of radioguided techniques for patients with parathyroid hyperplasia are unclear. Methods Between March 2001 and September 2002, 102 patients underwent neck exploration for primary (n = 77) and secondary/tertiary (n = 25) hyperparathyroidism. All patients received an injection of 10 mCi of Tc-99m sestamibi the day of surgery. Using a gamma probe, intraoperative scanning was performed, looking for in vivo radionuclide counts > background to localize abnormal parathyroid glands. After excision, radionuclide counts of each ex vivo parathyroid gland were determined and expressed as a percentage of background counts. Results Although patients with single adenomas had higher mean background radionuclide counts, the average in vivo counts of all enlarged glands were higher than background. Notably, in vivo counts did not differ between adenomatous and hyperplastic glands, suggesting equal sensitivity for intraoperative gamma detection. Ectopically located glands were identified in 22 cases and all were accurately localized using the gamma probe. Postresection, mean ex vivo radionuclide counts were highest in the single parathyroid adenomas and lowest in hyperplastic glands. Importantly, in all hyperplastic glands, the ex vivo counts were >20%. Conclusions In patients with hyperparathyroidism, radioguided surgery is a sensitive adjunct for the intraoperative localization of both adenomatous and hyperplastic glands. In this series, all 180 enlarged parathyroids were located with the gamma probe. We have also shown that the “>20% rule” for ex vivo counts not only applies to parathyroid adenomas but also to hyperplastic glands. Therefore, radioguided resection is equally effective and informative for both adenomatous and hyperplastic glands.