INTRAOPERATIVE URINARY CYCLIC-AMP MONITORING IN PRIMARY HYPERPARATHYROIDISM

Objective This study examined the utility of intraoperative urinary cy clic 3'5' adenosine monophosphate (UcAMP), an indicator of parathyroid (PTH) hormone end-organ activity, as a''biochemical frozen section,'' signaling the real-time resolution of PTH hyperactivity during surger y for primary hyperparathyroidism. Summary Background Data The unsucce ssful initial neck exploration for primary hyperparathyroidism, leavin g the patient with persistent hyperfunctioning parathyroid tissue, res ults in part from the surgeon's inability intraoperatively to correlat e a gland's gross appearance and size estimation with physiologic func tion. Preoperative imaging, intraoperative imaging, and intraoperative histologic/cytologic surveillance have not resolved this dilemma. Met hods Twenty-seven patients underwent a prospective intraoperative UcAM P monitoring protocol. The patients all had a clinical diagnosis of pr imary hyperparathyroidism and an average preoperative serum calcium of 12.0 +/- 0.3 mg/dl. UcAMP was assayed intraoperatively using 20-minut e nonequilibrium radioimmunoassay providing real-time feedback to the operating team. Results All patients had an elevated UcAMP confirming PTh hyperactivity at the beginning of the procedure. One patient, subs equently found to have an supernumerary ectopic adenoma, had four norm al glands identified intraoperatively, and his intraoperative UcAMP va lues corroborated persistent hyperparathyroidism. the UcAMP of the rem aining 26 patients decreased from 7.0 +/- 1.1 to 2.7 +/- 0.7 nm.dl GF (p < .00005) after complete adenoma excision, and they remain normocal cemic. The protocol provided useful and relevant information to the op erating team, and aided in surgical decision-making, in 10 of the 27 c ases (37%). Conclusion Intraoperative biochemical surveillance with uc AMP monitoring reliably signals resolution of PTH hyperfunction. ft is a useful adjunct to the surgeon's skill, judgment, and experience in parathyroid surgery.