RADIO-GUIDED SURGERY IN PRIMARY HYPERPARATHYROIDISM: CLINICAL INDICATIONS AND TECHNICAL PROCEDURE

AIM: The purpose of the present study was to assess the utility of the intraoperative gamma probe technique in a group of 128 patients suffering from primary hyperparathyroidism (PH). METHODS: In view of surgery, these patients were homogeneously subjected to a diagnostic protocol comprising double tracer scintigraphy ((99mTc)-Pertecnetate/(99mTc)-MIBI) and neck echotomography, carried out in a single session. They were then all operated on by the same surgical team. RESULTS: In 97 patients with scintigraphic and echographic evidence of single parathyroid enlargement and normal thyroid gland, mini-invasive radio-guided surgery (MRS) was planned. In 94 of these 97 patients (96%) MRS was carried out successfully by removal of a single parathyroid adenoma (PA) through a small cutaneous incision of 2-2.5 cm; in the remaining 3/97 patients (3.1%), it proved necessary to convert to bilateral surgical exploration of the neck following intraoperative diagnosis of a parathyroid carcinoma in 2 cases and of multiglandular pathology (MGP) suggested by the persistence of elevated values of intraoperative parathormone (PTH) in 1 case. It should be pointed out that the use of IGP enabled us to carry out limited surgical exploration in 18 of 23 patients who had previously undergone operation on the thyroid and/or parathyroids. In a second group of 31 patients with presumed preoperative diagnosis of MGP (5 cases) or nodular goitre concomitant with PH (26 cases), IGP was used in the course of standard bilateral surgical exploration of the neck and enabled us to locate: an ectopic parathyroid gland in the thymus in 1 case of MGP, a PA in the deep levels of the neck in 2 cases with goitre and an ectopic PA at the bifurcation of the carotid in 1 other case with goitre. It should however be specified that in certain other patients with goitre it proved difficult intraoperatively to distinguish thyroid nodes from a PA adhering to the thyroid. CONCLUSIONS: On the basis of the data to emerge from the present study we can conclude that: 1) in patients with PH presenting a scintigraphic and echographic picture indicating single PA and normal thyroid with high probability, the IGP technique proves effective in carrying out an MRS; 2) 37 MBq of (99mTc)-MIBI are an adequate dose for the correct performance of MRS; 3) a rapid intraoperative dose of PTH is to be recommended so as to confirm complete removal of the hyperfunctioning parathyroid tissue; 4) MRS may be employed successfully also in those patients previously subjected to thyroid or parathyroid surgery for the purpose of limiting the surgical trauma connected to reintervention and, therefore, to reducing the risk of complications; 5) IGP would not appear to be recommendable in patients with PH and concomitant goitre, with the possible exception of ectopic PA.