Intraoperative parathyroid aspiration and parathyroid hormone assay as an alternative to frozen section for tissue identification

Most people would agree that successful parathyroidectomy depends on two im portant variables: the surgeon's recognition and excision of the abnormal p arathyroid gland(s) and the pathologist's confirmation that the removed tis sue is parathyroid tissue. Frozen section is usually employed to confirm th e identity of parathyroid tissue, but occasionally confirmation cannot be m ade without a permanent section, as with intrathyroidal glands. This study proposes a new method of expeditious and easy confirmation of parathyroid t issue utilizing the immunoassay for quick measurement of intraoperative par athyroid hormone (IOPTH), By directly aspirating the suspected adenoma, the assay becomes a rapid diagnostic tool that can be used as an alternative t o frozen section. In cases where the surgeon is already planning to employ the assay, the elimination of frozen section is cost-effective. Intraoperat ive aspiration of histologically confirmed parathyroid adenomas was perform ed on 12 consecutive patients undergoing parathyroid surgery. Parathyroid g lands were aspirated with a 22-gauge syringe after gland excision. Aspirate s were placed in 1 to 3 ml of buffered saline. A similar process was perfor med on 12 thyroid controls. Specimens were centrifuged, aliquotted, and sto red at -70 degreesC, The parathyroid hormone value was analyzed electively by rapid assay and the values recorded. For all parathyroid aspirates, the rapid assay value was a 1500 pg/ml, exceeding the uppermost limit of the di agnostic chart. Values for thyroid aspirates ranged from 58 to 85 pg/ml (me an 75.7 pg/ml), In all cases tissue confirmation was achieved with permanen t section. Values were 100% sensitive and specific. Measurement of PTH from intraoperative aspiration of suspected parathyroid adenomas is clinically useful in patients for whom frozen section would routinely be employed. Val ues > 1500 pg/ml secure the tissue diagnosis. There is no additional cost i n cases where IOPTH monitoring is already being utilized to confirm cure. T he elimination of frozen section could be cost-effective and, for some inst itutions, actually decrease the operating time as the IOPTH assay takes onl y 15 minutes. PTH assay is an accurate diagnostic technique and to date is 100% sensitive and specific for differentiating between parathyroid tumors and thyroid nodules.