Electrical Impedance Spectroscopy to Aid Parathyroid Identification and Preservation in Central Compartment Neck Surgery: A Proof of Concept in a Rabbit Model

Background. Accurate identification of parathyroid glands during thyroid surgery is crucial to avoid postthyroidectomy hypocalcemia. Electrical impedance spectroscopy has the potential to differentiate between tissues of different morphology. The aim of this study was to determine the electrical impedance patterns of the thyroid, parathyroid, and other soft tissue structures in the rabbit neck. Methods. The central compartments were exposed in 9 freshly culled New Zealand White rabbits. In situ and ex vivo electrical impedance was measured from thyroid lobes, external parathyroid glands, adipose tissue, and strap muscle using the APX100 device. Specimens of all identified glands were sent for histopathology examination. Results. Histology confirmed correct identification of all excised thyroid and parathyroid glands. The impedance was higher for thyroid tissue at lower frequencies and for parathyroid tissue at higher frequencies. Ex vivo electrical impedance spectra were significantly higher compared with the in situ spectra across all frequencies for thyroid and parathyroid tissues (P < .001). The ratio of low to high frequency in situ impedance of thyroid, parathyroid, and muscle was significantly different (P < .001), allowing for differentiation between these tissues. Conclusion. The electrical impedance spectra of rabbit thyroid and parathyroid glands are distinct and different from each other and from skeletal muscle. If these results are replicated in human tissue, they have the potential to improve patient outcomes by achieving early identification and preservation of parathyroid glands.