[Radioguided surgery for primary hyperparathyroidism. Experience in 75 cases]

To report feasibility and efficacy of radioguided mini invasive hyperparathyroidism surgery.

From November 1998 to August 2000, 75 patients with primary hyperparathyroidism have been operated on by radioguided surgery within 90 to 180 minutes following i.v. injection of a diagnostic dose of MIBI and after parathyroid scanning with planar and oblique views. Exclusion criteria were thyroid pathology requiring surgery and suspicion of multiple endocrine neoplasia. A 20% step-up between the background noise and tissue uptake was the diagnostic threshold for parathyroid hyperfunctioning tissue.

A 20% step-up was observed in only 17% of cases overall; all cured, but two. Various angles of application of the probe can result in significant discrepancies of recorded uptake for the same spot. These results demonstrate a physiological step-up between the ipsilateral unaffected upper and lower quadrants of the neck (range: -17 to -8%), because of the proximity of supraortic vessels (upper neck-upper mediastinal gradient: -44 to -30%). Therefore, significant ratios are meaningful only between either the symmetrical left and right controlateral quadrants respectively, and not between the upper and the lower ipsilateral quadrants. Eleven per cent (8/75) of preoperative scannings were non-contributory, and probe detection was contributory in 3/8 cases only.

Benefit of the technique is limited in routine, but it can be helpful in redo cases if the offending gland is not located in close surroundings of tissues physiologically taking up the radiopharmaceutical (salivary glands, great vessels and heart).