Intra-operative parathyroid hormone monitoring in secondary hyperparathyroidism: is it useful?

Objectives: To assess the use of intra-operative parathyroid hormone (PTH) level monitoring as a predictor of persistent hypoparathyroidism after total parathyroidectomy in renal hyperparathyroidism. Setting: University Teaching Hospital Otorhinolaryngology and Head and Neck Surgery Unit. Participants: All patients with renal hyperparathyroidism undergoing parathyroidectomy between January 2004 and July 2005. Twenty-nine patients were identified. Main outcome measures: Comparison is made between pre- and intra-operative PTH levels (ioPTH) in patients who at 3 months postoperatively maintained hypoparathyroidism and patients who did not. Results were analysed to see whether ioPTH predicts maintenance of the hypoparathyroid state. Results: The mean preoperative PTH level was 932 pg/L (range: 58-1808). The mean postoperative PTH level was 147 pg/L (range: 16-498). The mean 3-month PTH level was 47 pg/L (range: < 1-515). The mean postoperative PTH level for patients with a persistently high PTH level at 3 months was 286 pg/L (range: 272-299), compared with 63 pg/mL (16-160) in patients remaining normparathyroid, and 159 pg/L (range: 39-498) for patients with persistent hypoparathyroidism. If the normoparathyroid state is strictly considered to be failure following total parathyroidectomy, ioPTH is not predictive of hypoparathyroidism. However, ioPTH is indicative of biochemical resolution of the hyperparathyroid state (normo- or hypoparathyroidism). Conclusion: We conclude that the use of ioPTH monitoring in the surgical management of secondary hyperparathyroidism fails to predict persistent hypoparathyroidism following total parathyroidectomy, but does predict biochemical resolution of hyperparathyroidism.