Background: Radioguided surgery represents a validated technique for the detection
and the excision of abnormal parathyroid glands responsible for primary hyperparathyroidism
(PHPT). To date little attention has been paid as to how the characteristics of gamma-probes can influence
surgical procedure and time, thus having an impact on postoperative morbidity, hospitalization
Methods: We designed a new prototype of gamma-probe, the Gonioprobe, and tested its clinical
utility in the operating room. Gonioprobe, thanks to its 5 scintillating independent crystals, performs
the dual function of Navigator and Lock-on-target. These characteristics allow the immediate
guidance of the surgeon’s hand towards the source with very high precision, and with a much
higher spatial resolution than commercial probes. Gonioprobe was used during intervention to detect
abnormal parathyroid tissue, and to ensure no radioactivity in surgery bed after adenoma removal.
Results: We tested our gamma-probe on parathyroid adenomas particularly difficult to identify at a
visual inspection due to anatomy modifications from previous neck surgery and/or characterized by
uncommon localization. Moreover, parathyroid adenomas were hardly removable due to the
proximity to the esophagus, neck vessels and/or recurrent laryngeal nerve (RLN). An intraoperative
nerve monitoring system was used to protect the recurrent laryngeal nerve from injuries.
Parathyroid hormone (PTH) assay and frozen biopsy confirmed the successful excision of the adenomas.
Conclusion: The intraoperative use of the innovative Gonioprobe along with the nerve monitoring
system allowed an accurate and safe removal of parathyroid adenomas and offered a significant advantage
by reducing surgical time and postoperative complications, as well as hospitalization and