Fig. 1Intraoperative parathyroid hormone (PTH) dynamics after successful excision of a single hyperfunctioning parathyroid gland. With a drop at the 10-minute post-excision interval of 79% from the highest PTH level, this hormone dynamic predicts a postoperative return to eucalcemia and successful parathyroidectomy. Dotted line shows time of gland excision.
Fig. 2Intraoperative parathyroid hormone (PTH) dynamics during successful parathyroidectomy in a patient presenting with multiglandular disease. An intraoperative pre-incision level of 122 pg/mL, excision of an abnormal left inferior parathyroid gland led to a rise of PTH level to 179 pg/mL. After excision of this hypersecreting gland, the PTH assay showed no decrease at 5 minutes (120 pg/mL) and 10 minutes (98 pg/mL). Continued neck exploration revealed another abnormal hypersecreting parathyroid gland. The third and fourth glands appeared grossly normal. The expected hormone level did not decrease significantly until excision of the second hyperfunctioning parathyroid gland. With a 77% decrease in the 10-minute sample (24 pg/mL) compared with the second pre-excision plasma sample (105 pg/mL), no remaining hypersecreting parathyroid tissue was present. Dotted line shows time of gland excision.
Fig. 3Intraoperative parathyroid hormone (PTH) dynamics in a patient where the intraoperative >50% PTH decrease criterion is not met at 10 minutes after parathyroid gland excision or if the decline dynamics are equivocal (e.g., borderline PTH drop at 50%). In the majority of patients, the “>50% intraoperative PTH drop” criterion is achieved with an additional 20-minute PTH measurement that excludes a false negative result, accurately predicts postoperative success and prevents unnecessary bilateral neck exploration. Dotted line shows time of gland excision.
Table 1Guidelines from the Fourth International Workshop on the Management of Asymptomatic Primary Hyperparathyroidism [29]
Measurement |
|
Serum calcium (>upper limit of normal) |
1.0 mg/dL (0.25 mmol/L) |
Skeletal |
A. BMD by DXA: T-score <–2.5 at lumbar spine, lumbar spine, total hip, femoral neck or distal 1/3 radiusa
|
B. Vertebral fracture by X-ray, CT, MRI, or VFA |
Renal |
A. Creatinine clearance <60 cc/min |
B. 24-hour urine for calcium >400 mg/day (>10 mmol/day) and increased stone risk by biochemical stone risk analysisb
|
C. Presence of nephrolithiasis or nephrocalcinosis by X-ray, ultrasound, or CT |
Age |
<50 years |
Table 2Most Common Intraoperative PTH Criteria for Prediction of Operative Success [37]
Criterion |
Protocol for operative success |
PPV, % |
NPV, % |
Overall accuracy, % |
Miami |
A >50% ioPTH drop from the highest either pre-incision or pre-excision at 10 minutes after excision of all hyperfunctioning parathyroid gland(s) |
99.6 |
70.0 |
97.3 |
Vienna |
A >50% ioPTH drop from the pre-incision value within 10 minutes after excision of all hyperfunctioning parathyroid gland(s) |
99.6 |
60.9 |
92.3 |
Rome |
A >50% ioPTH drop from highest pre-excision level and/or ioPTH level within normal range at 20 minutes post-excision, and/or ≤7.5 ng/L less than the value at 10 minutes post-excision |
100 |
26.3 |
83.8 |
Halle |
An ioPTH decay to <35 ng/L within 15 minutes after excision of all hyperfunctioning parathyroid gland(s) |
100 |
14.2 |
65 |