Role of gamma probes in performing minimally invasive parathyroidectomy in patients with primary hyperparathyroidism: optimization of preoperative and intraoperative procedures

OBJECTIVE: In the last decade, surgery of primary hyperparathyroidism (HPT) due to a solitary adenoma has moved on from the traditional wide bilateral neck exploration (BNE) to more limited approaches such as unilateral neck exploration and minimally invasive parathyroidectomy. DESIGN: To define the role of intraoperative gamma probe and injection of a low (99m)Tc-MIBI dose in performing minimally invasive radio-guided surgery (MIRS) in HPT patients with a solitary parathyroid adenoma. METHODS: From September 1999 to July 2002, 214 patients with primary HPT entered the study. All patients were preoperatively investigated by a (99m)Tc-pertechnetate/MIBI subtraction scan and high-resolution neck ultrasound. The intraoperative technique we developed differs from other previously described techniques being based on the injection of a low (37 MBq) MIBI dose in the operating theatre a few minutes before the beginning of intervention. RESULTS: On the basis of scan/ultrasound findings 147 patients were selected for a MIRS and 144 of them (98%) were successfully treated by this approach: a solitary parathyroid adenoma was removed through a small 2-2.5 cm skin incision with a mean operative time of 35 min, and a mean hospital stay of 1.2 days. In the other 67 patients with scan/ultrasound evidence of concomitant nodular goiter (n=45) or multi-gland disease (n=13) or with a negative scan (n=9), the gamma probe was utilized during a traditional BNE. A low 37 MBq MIBI dose proved to be sufficient to perform a MIRS; moreover it delivered to the patient and surgeon a low, negligible, radiation exposure dose. CONCLUSIONS: The combination of a (99m)Tc-pertechnetate/MIBI subtraction scan and neck ultrasound appears to be an accurate imaging protocol in selecting primary HPT patients as candidates for a MIRS. A MIBI dose as low as 37 MBq injected in the operating theatre just before the start of surgery appears to be adequate to perform radio-guided surgery.