Different operative protocols for minimally invasive radioguided parathyroidectomy. A randomized prospective study

Aim: The aim of this study was to establish the optimal interval between radiofarmaceutical administration and the beginning of surgical exploration in patients undergoing minimally-invasive radioguided parathyroidectomy (MIRP). Patients and Methods: Forty-three consecutive patients (35 women (81.4%) and 8 men (18.6%), median age 63 years, range 25-82) with primary hyperparathyroidism in whom an enlarged parathyroid (PT) gland has been previously detected by neck ultrasonography were enrolled in the study. Patients were randomized to receive an intravenous injection of 570 MBq (Group A, 21 patients) or 50-70 MBq (Group B, 22 patients) 99mTc-sestamibi, 90-120 minutes and 30-45 minutes prior to surgery, respectively. In Group A patients radiopharmaceutical administration was performed in a protected area, and four early scintigrams were obtained. If the scan was considered positive M1RP was carried out. Group B patients had already undergone PT scintigraphy 8-12 days before and were injected in the operating room. Results: Age, the main biochemical parameters, and the size of the removed PT gland did not differ (p=NS) between Groups. Intraoperative nuclear mapping using a hand-held 11-mm gamma probe and quantitative gamma camera counting in the four quadrants was obtained. A 2-3 cm incision was made, and the PT gland excision was guided by the probe, resulting in a decline in radioactivity in the corresponding quadrant. Intraoperative quick PTH was routinely assayed. MIRP was successfully performed in all Group A patients, while 5 of 22 (22.7%) Group B patients required conversion to a more extensive neck exploration. The average operative time was 42_+8 and 72_+ 18 minutes (p<0.01) in Groups A and B, respectively. Final pathology confirmed a PT adenoma in each patients. All patients were cured of the disease at 6-18 months followup. Conclusions: MIRP performed after peroperative PT scintigraphy, and intraoperative quick PTH assay represents the procedure of choice for patents with a solitary PT adenoma previously visualized by neck ultrasonograpy.