Results
A >50% decrease of PTH within 10 min compared to the highest pre-excision value occurred in 156/188 patients (83%). In 12 patients >50% decrease of PTH was obtained after 20 minutes (6.4%) (Table 1). The characteristics of the 12 patients of this group are shown in Table 2. Total >50% decrease of PTH within 20 minutes was obtained in 168/188 patients (89.4%); postoperative normal calcemia and PTH were found in 167 patients and persistent postoperative hypercalcemia with increased value of PTH was found in 1 patient. In the remaining 20 patients (10.6%) values of PTH remained substantially unchanged or decreased less than 50%. In these patients the surgical procedure went on and bilateral neck exploration was performed. An additional pathologic parathyroid was removed in 9 cases, a third in one case. In these cases histology exams showed hyperplasia in 5 cases, double adenoma in 4 and single adenoma associated to hyperplasia in 1. In the other 10 cases further neck exploration by a standard cervical approach was negative and in four of these persistent postoperative hypercalcemia was demonstrated, whereas in six patients postoperative normal calcemia and PTH were found.
Final histology showed a parathyroid adenoma in 150 patients, hyperplasia in 35, carcinoma in 3.
The overall operative success was 97.3%, with a 4.8% incidence of multiglandular disease (9 cases).
Median duration of surgery was 60 minutes (range 40–80). Surgical complications have been observed in 3 patients: 2 transient recurrent laryngeal nerve paresis and 1 hematoma necessitating reoperation. Transient hypocalcemia occurred in 24 cases (12.7%) and was treated with calcium and vitamin D per os with resolution within 1 month. No cases of permanent hypocalcemia were observed. There were no wound complications and no perioperative deaths.
Median postoperative recovery was 2 days (range 1–3). Intraoperative PTH monitoring was accurate in predicting operative success or failure in 96.3% of cases. Thus the method had a sensitivity of 96.5%, a specificity of 93.3%, a positive predictive value of 99.4% and a negative predictive value of 70% (Table 3).
We compared the characteristics of patients in which there was a >50% decrease of PTH within 10 minutes (group A) to those with no decrease or late decrease (group B). We found no significant difference for the age and for preoperative localization studies, while the mean value of baseline PTH was significantly lower in the first group (Table 4).