A new classification of parathyroid glands to evaluate in situ preservation or autotransplantation during thyroid surgery

The indication for autotransplantation of parathyroid glands is still controversial. A new classification of parathyroid glands based on the positional relationship among parathyroid glands, thyroid gland and thymus was created to decide in situ preservation or autotransplantation during thyroid surgery. A retrospective study included patients with papillary thyroid cancer who underwent total thyroidectomy with bilateral central lymph node dissection between November 2014 and November 2016. According to the application of the new classification (December 2015–November 2016) or traditional method (preservation of all functional parathyroid glands in situ, November 2014–November 2015), the patients were divided into new classification and traditional groups. The traditional method was utilized in 288 patients who underwent surgery during the first half of the study, while the new classification was applied to 249 patients during the latter half of the study. The incidence of transient hypoparathyroidism was 43.0% (107/249) in new classification group and 35.8% (103/288) in the traditional group, respectively (P = .093). The corresponding incidence of permanent hypoparathyroidism was 0.4% (1/249) and 4.5% (13/288) (P = .002). The new classification of parathyroid glands potentially reflects the difficulty of preservation and helps to make a reasonable decision on preservation or autotransplantation of a parathyroid gland, which may minimize the incidence of permanent hypoparathyroidism.