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Parathyroidectomy: Intraoperative Monitoring

Most commonly, a patient presenting for parathyroidectomy will have hypercalcemia, which is ideally controlled and medically managed prior to surgery. Radioactive scanning, ultrasound, and other imaging pre-operatively also allows the surgeon to locate and dissect appropriately to remove only those gland(s) which are pathologic. Several modalities of monitoring are important for a parathyroidectomy:

  • Standard ASA monitoring – including SpO2, HR, NIBP, temperature, capnography.
  • Electrolyte monitoring – the gold standard of monitoring successful surgery is a >50% drop in the PTH level. This is feasible due to the relative short half-life of parathyroid hormone (3-5 minutes) which allows for serial assessment during the surgery by the anesthesiologist
    • Each surgeon or hospital will have its own protocol for testing; most commonly, at least 4 levels are tested (pre-incision, pre-gland removal, 5 minutes post-removal, 10 minutes post-removal)
    • Because of the need for frequent labwork, placement of a large bore peripheral IV or an arterial line is needed
  • Neuromonitoring – due to the course of the recurrent laryngeal nerves posterior to the thyroid/parathyroid glands, the use of intraoperative neuromonitoring is frequently (but not always) employed. This is accomplished with a NIMS tube, which aligns with the vocal cords during intubation and will alert the surgery team if/when their dissection stimulates those nerves (and therefore the cords).
    • This is commonly employed during re-operation for a failed parathyroidectomy, or when imaging confirms close proximity of the pathologic gland to a recurrent laryngeal nerve
    • When neuromonitoring is employed, long-acting muscle relaxant should be avoided. If a non-depolarizing muscle relaxant is used, proper use of a twitch monitor prior to incision is recommended to aid in reversal.


  1. Irvin GL, et al. “A New Approach to Parathyroidectomy.” Annals of Surgery. 1994; 219(5): 574 Link