Incidental parathyroidectomy during total thyroidectomy as a possible risk factor of hypocalcemia. Experience of a single center and review of literature

Context. Post-operative clinical and biochemical hypocalcemia is a common complication of thyroid surgery and the correlation with incidental parathyroidectomy (IP) remains controversial. Objective. To evaluate the incidence of IP during TT, its correlation to early post-surgery hypocalcemia, and its potential risk factors. Patients and Methods. 77 consecutive patients submitted to thyroid surgery between January 2018 and December 2019. Patients were divided into the IP-Group and the Non-IP-Group. Statistical multivariate analysis was performed to identify the risk of IP. Results. IP was evident in 22 (28.5%)patients underwent TT, TT with lymph node dissection of the central compartment (CLND) and reoperation for previous hemithyroidectomy with CLND. Early symptomatic hypocalcemia 24 hours after TT was demonstrated in 12/22 (54.5%) patients, with PTH value of <14pg/mL in 7/12 (58.3%) patients, and in 6 of these 7 patients (85.7%) the PTH value was <6.3pg/mL. In 5/22 (22.7%) patients the IP was associated with biochemical hypocalcemia <8.4mg/dL, and in 5/22 (22.7%) patients anatomical damage was not associated with a reduction in plasma calcium levels. The severity of early post-op hypocalcemia was not correlated with the number of parathyroid glands left in situ. The multivariate analysis didn’t show statistically significant values between the clinical-pathological variables and increased risk of IP. Conclusions. No IP clinical-pathological risk factors have been identified during thyroid surgery. In all cases of TT, with or without CLND, the meticulous identification of the parathyroid glands, whose incidental removal is frequently associated with clinical and biochemical hypocalcemia, is recommended.