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Background: Sample collection site may affect the dynamics of intraoperative parathyroid hormone monitoring (IPM) and influence surgical decisions., Methods: We prospectively studied 45 patients undergoing parathyroidectomy for primary hyperparathyroidism. The IPM cure criterion was a decrease in peripheral vein (PV) parathyroid hormone (PTH) of >50% at 10 minutes after gland excision. PTH samples were collected simultaneously from PV and central vein (CV) and compared for PTH decay, the incidence of >50% PTH decay, and the incidence of normal PTH values after gland excision., Results: Mean PTH levels were significantly higher from the CV before and after gland excision. Mean PTH decay 10 minutes after gland excision was 89% PV versus 88% CV, resulting in mean PTH levels of 27 +/- 23 and 39 +/- 35 pg/mL, respectively (P < .0001). At 5 minutes, >50% decay in PTH was present in 98% PV versus 88% CV samples. By 10 minutes, the incidence of >50% PTH decay was equivalent (98%). This yielded normal range PTH levels from the PV versus CV in 90% versus 76% of patients at 5 minutes, 96% versus 89% at 10 minutes, and 95% versus 81% at 20 minutes. Of 45 patients, 44 (98%) are normocalcemic at a mean follow-up of 6.3 months. IPM predicted the single operative failure., Conclusions: CV sampling produces significantly higher PTH levels. Surgeons sampling from a PV may observe a >50% decrease in PTH and normal range PTH values starting 5 minutes after gland excision. Surgeons who sample from the CV and require normalization of PTH levels may have to wait longer and/or continue potentially unnecessary neck exploration.

Background: Intraoperative parathyroid hormone (IOPTH) monitoring in parathyroidectomy for multigland disease is less clear than for single-gland disease. This study assesses the role of IOPTH for hyperplasia., Methods: A prospective database revealed 45 patients with hyperplasia undergoing parathyroidectomy utilizing IOPTH from February 1999 to August 2003., Results: Twenty-six females and 19 males had a mean age of 55 years. Twenty-two patients underwent total parathyroidectomy. Twenty-three patients underwent subtotal parathyroidectomy. Twenty-seven patients (60%) had a drop of IOPTH greater than 50% at 10 minutes after removal of all presumably abnormal parathyroid tissue. Nine additional patients (20%) had an IOPTH drop greater than 50%, but continued exploration revealed more abnormal tissue. Nine patients failed to decrease greater than 50%, and exploration was continued. A final IOPTH less than 35 pg/mL or a greater than 90% decrease from baseline was predictive of a successful operation in 40 patients. The 5 patients who did not meet this criteria remained hyperparathyroid., Conclusions: IOPTH identifies sporadic hyperplasia and guides completeness of resection for patients with known hyperplasia. However, more rigid criteria are required than for adenomas. Failure to achieve appropriate decreases in IOPTH should prompt further neck exploration or a search for a mediastinal gland.

Background: Intraoperative intact parathyroid hormone (iPTH) is being used to confirm complete excision of hyperfunctioning parathyroid tissue. It is uncertain whether normalization of intraoperative iPTH levels accurately predicts long-term postoperative iPTH values., Methods: Fifty-two consecutive patients with primary or secondary hyperparathyroidism underwent parathyroidectomy with measurement of intraoperative iPTH. Ten patients were excluded due to incomplete laboratory follow-up. Follow-up serum calcium and iPTH levels were measured at 1- and 3-month intervals., Results: Before operation, the mean serum iPTH level was 249 pg/mL (SD=208) and mean serum calcium level was 11.4 +/- 0.9 mg/dL (+/- SD). In all but 4 patients, final intraoperative iPTH levels normalized to less than 67 +/- 41 pg/mL (mean, 35 pg/mL). One week after operation, serum calcium levels had returned to normal (mean, 9.4 +/- 1.1 pg/mL), which directly correlated with the final intraoperative serum iPTH values (Pearson correlation, r = -.434; P <.01). By 1 month, all but 2 patients were normocalcemic (mean, 9.4 +/- 0.9 pg/mL) with a mean iPTH level of 74.8 +/- 82 pg/mL. There was no correlation between final intraoperative and postoperative serum iPTH values (r =.099; P <.533). Both patients with persistent hypercalcemia at 1 month had appropriate intraoperative decreases in iPTH values., Conclusions: Intraoperative serum iPTH levels significantly correlate with postoperative serum calcium levels but not with postoperative serum iPTH levels. There was a 4.8% failure rate in the correction of postoperative serum calcium levels and a 29% failure rate in the normalization of postoperative serum iPTH levels.