Methods
We conducted a retrospective study on 239 patients operated on for primary hyperparathyroidism in our surgical department between May 2003 and December 2012. 202 patients were female and 37 were male, median age was 58 years (range 19–85). Before operation hypercalcemia and elevated PTH levels were observed in all patients.
In order to localize hyperfunctioning glands, a TC99m-sestamibi scan (MIBI) was performed in 191 patients (79.9%): pathologic parathyroid was localized in 178 cases (93.2%). High resolution ultrasound was associated in 233 patients and pathologic parathyroid was localized in 146 (62.7%). Association of ultrasound and 99m Tc-sestamibi scan localized hyperfunctioning parathyroid in 163/174 patients (93.7%). SPECT-TC was performed on 140 patients and hyperfunctioning parathyroid was localized in 134 (95.7%). Association of SPECT-TC and ultrasonography localized hyperfunctioning parathyroid in 121/122 patients (99.2%).
188 patients underwent a focused parathyroidectomy associated to a rapid intraoperative PTH assay monitoring. All patients had normal renal function (serum creatinine value ranging from 0.7 to 1.2 mg/dL) and gave informed consent for the procedure. All operations were performed under general anesthesia with endotracheal intubation and by the same team of surgeons, who were highly experienced in parathyroid surgery. Blood samples were collected: 1) at pre-incision time, 2) at 10 min after gland excision and 3) at 20 min after excision, if a sufficient reduction of PTH value was not observed. The STAT-IntraOperative-Intact-PTH Chemilluminescence immunoassay semiautomated mobile system (Future Diagnostics, Wijchen, Netherlands) was used within the surgical suite complex for the intraoperative quantitative determination of PTH levels in EDTA plasma.
The study has been performed in accordance with the Declaration of Helsinki. Ethical approval for our study was obtained from institutional ethical committee of Monserrato University Hospital, Cagliari, Italy. Informed consent was obtained from participants for their inclusion in our study.
On the bases of the Irvin criterion, an intra-operative PTH drop >50% from the highest either pre-incision or pre-excision level after parathyroid excision was considered a surgical success. A PTH drop of <50% from the highest basal value within 20 min after gland excision and/or a residual PTH-20 min level higher than the reference range were considered predictor of persistent hyperfunctioning parathyroid tissue and further surgical exploration was required.