Intraoperative Parathyroid Hormone Aspiration: Implementation and Technique

Abstract

Introduction: Fine-needle aspiration with parathyroid aspiration has been described as a preoperative adjunct to confirm parathyroid tissue. However, intraoperative parathyroid hormone (IOPTH) wash can also be used to replace the need for frozen section confirmation of parathyroid tissue during parathyroid exploration. This video describes the implementation and validation of the operative technique. Materials and Methods: Preclinical implementation—Ex vivo aspiration of two hyperfunctional parathyroid glands and two thyroid lobectomy specimens prospectively stored in our tissue bank was evaluated using the IOPTH assay (Roche E411) to establish reproducibility and reference standards. Tissue IOPTH samples were centrifuged and run just as serum IOPTH samples, with no homogenization required. Clinical implementation—During parathyroid exploration, 1 mL of normal saline was drawn into a 3 mL syringe. After resection of each culprit parathyroid gland or glands, a 25-gauge needle was passed back and forth through the resected tissue several times with aspiration until a flash was seen in the hub. The aspirate was sent to the laboratory for analysis of an IOPTH level, the parathyroid gland was weighed intraoperatively, and the IOPTH tissue result was reported back to the operating room. The hyperfunctional parathyroid tissue was later sent for routine histology analysis. Results: In preclinical implementation, the mean IOPTH level of the hyperfunctional parathyroid tissue was 5000 pg/mL vs 86 pg/mL for thyroid tissue. Clinically, from July 1, 2015, to October 31, 2015, there were 72 IOPTH aspirates in 55 patients. Overall, 68 samples (94.4%) were identified to be enlarged hyperfunctional parathyroid glands on final pathology analysis with mean tissue IOPTH level of 3533 ± 661 pg/mL. Conversely, three samples with mean PTH 15 ± 6 pg/mL were confirmed on final pathology analysis to be thyroid, thymus, and lymph node tissues, respectively. There was one false positive result with a PTH aspirate value of 968 pg/mL, which on final pathology analysis was extrathyroidal thyroid tissue. The mean time to receipt of tissue IOPTH result was 16 minutes (range 14–20). For hyperfunctional parathyroid glands, IOPTH sensitivity was 100%, positive predictive value was 98.6%, and the negative predictive value was 100%. Conclusion: Intraoperative PTH aspirate analysis can be used to replace frozen section confirmation of parathyroid tissue during parathyroidectomy. The technique is easy to implement, provides prompt results, has a positive predictive value of 98.6%, and readily differentiates parathyroid tissue from other nearby tissues during parathyroid exploration. This project used the Tissue and Research Pathology Services/Health Sciences Tissue Bank which receives funding from P30CA047904. No competing financial interests exist. Runtime of video: 4 mins 6 secs