Methods for identifying parathyroid glands – a literature review

Introduction: Identifi cation of the parathyroid glands (PG) is an important yet challenging aspect of thyroid and parathyroid surgery. Failure to do so during thyroidectomy may lead to transient or permanent hypocalcemia, with the latter representing serious complications (defected neurotransmission) causing life-long morbidity, and with parathyroidectomy leading to persistent hyperparathyroidism. Identifi cation of PG during surgery is often a challenge, and that’s the reason to develop new innovative methods. The aim of this article is to present a summary of the most used and available methods in daily practice for identifi cation of the parathyroid glands during thyroid and parathyroid surgery. Methods: The systematic review was conducted by searching the medical literature in PubMed, Web of Science, and Google Scholar using key terms “identifi cation,” “parathyroid,” “thyroid surgery,” and “fl uorescence.” The search yielded 189 articles, of which 15 relevant articles were selected, and 3 articles were added from Czech journals, according to their main focus on identifi cation and localization of the parathyroid glands during thyroid and parathyroid surgery. Results: Thyroidectomy identifi cation of PG is mainly achieved through visual inspection, and to do so, magnifying glasses from a microscope could be used. Currently, intra-operative optical methods such as fl uorescence or angiography with indocyanine green (ICG) could be of assistance. The identifi cation and localization of hyperfunctioning parathyroid glands (adenoma/ hyperplasia) is based on preoperative parathyroid imagining. Sonography with double-phase scintigraphy are predominantly used, and in case of a negative result, use fl uorocholine PET/ CT, fol lowed by PET/ MR. Besides using sonography CT or MR, although they’re not usually in fi rst line of imaging, they are irreplaceable with revision surgery. More than one preoperative imaging leads to a higher success rate in the identifi cation of PG, and with mini-invasive surgery, a shorter operating time could be achieved. Preoperatively, fi ne needle aspiration of parathyroid hormone or biopsy of pathologic PG could be used. Conclusion: Currently, identifi cation of the parathyroid glands is mainly achieved through visual inspection and is largely dependent on surgical experience. During thyroidectomy, fl uorescence or ICG angiography could be of assistance. Identifi cation and localization of hyperfunctioning parathyroid glands (adenoma/ hyperplasia) is based on preoperative imagining (sonography, scintigraphy, PET/ CT). Perioperative bio psy or measurement of parathyroid hormone can confi rm or exclude persistence of residual aff ected tissue, off ering the possibility to change the surgical strategy accordingly. Key words identifi cation – parathyroid – scintigraphy – PET/ CT – fl uorescence