Prospectives and surgical usefulness of perioperative parathyroid hormone assay in thyroid surgery

Hypocalcemia is the most frequent complication after thyroid surgery. The incidence varies and has been reported as ranging from 1.2 to 40%. Permanent hypoparathyroidism occurs in less than 3% of patients, whereas transient postoperative hypocalcemia is much more common. Postoperative hypoparathyroidism is traditionally detected by serial measurement of serum calcium concentrations and requires multiple venepunctures and, potentially, several days of hospitalization following the procedure. The parathyroid hormone (PTH) molecule is a polypeptide composed of an 84-amino acid sequence with an active amino terminal on one end and an inactive carboxyl unit on the other. Measurement of the intact PTH (iPTH) is an accurate representation of the true parathyroid state. In recent years, iPTH assay has been under investigation for thyroid surgery in many centers as an early iPTH measurement may be of value for prediction of postoperative symptomatic hypocalcemia, guiding the surgeon for parathyroid autotransplatation, and selection of patients requiring onset of calcium substitution or safe discharge home. This paper reviews the relevant medical literature published regarding the influence of PTH assay technology on the quality of thyroid surgery, as well as on the prevention of postoperative symptomatic hypocalcemia. Searches were last updated in April 2008.