A 55-year-old patient undergoes parathyroidectomy for primary hyperparathyroidism. Pre-operative sestamibi and 4D-CT localize a single right inferior parathyroid adenoma. Intra-operative PTH falls from 185 to 48 pg/mL at 10 minutes post-excision. By the Miami criterion, is the operation successful?

• A No — PTH must fall to normal range (< 65 pg/mL)
• B No — PTH must be measured at 15 and 20 minutes post-excision
• C Yes — a >50% fall from the highest pre-excision PTH value indicates cure ✓
• D Yes — any PTH fall confirms complete removal

Explanation

The Miami criterion for intraoperative PTH monitoring defines success as a fall of >50% from the highest pre-incision or pre-excision PTH value, measured at 10 minutes post-excision (given PTH's half-life of ~3–4 minutes). In this case: pre-op PTH = 185 pg/mL, post-excision PTH = 48 pg/mL, which represents a 74% fall — meeting the Miami criterion. PTH need not fall to the normal range for the Miami criterion to be satisfied; >50% reduction is sufficient. Alternative criteria (Vienna, Halle) require PTH to fall to normal range, but the Miami criterion only requires >50% drop.

Reference: Bailey & Love's Short Practice of Surgery, 27th ed.

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Written and medically reviewed by the StethoPrep medical team.