[The effect of operative approach selection on the protection of parathyroid function in thyroid cancer]

Objective: To investigate the effect of endoscopic thyroidectomy and open thyroidectomy on parathyroid function in patients with thyroid cancer. Methods: The clinical data of 73 patients with thyroid cancer who met the inclusion criteria in Zhengzhou Central Hospital Affiliated to Zhengzhou University from July 2018 to September 2019 were retrospectively analyzed, including 17 males and 56 females, aged 19-55 years. The patients underwent routine thyroidectomy (group A, n=31), oral endoscopic thyroidectomy by vestibular approach (group B, n=19) or transthoracic thyroidectomy (group C, n=23), and all patients received central neck dissection. The levels of parathyroid hormone (PTH) and serum calcium after operation were compared among three groups. SPSS 21.0 software and GraphPad Prism v6.01 were used for statistical analysis. Results: After operation, the mean levels of PTH and serum calcium in three groups were significantly decreased (all P<0.05). On the first day after operation, the mean level of PTH in group C was lower than that in group A [(12.3±9.0) vs. (22.2±13.2) pg/ml, t=3.04, P=0.004] or group B [(12.3±9.0) vs. (20.0±14.1) pg/ml, t=2.09, P=0.043], and also the level of serum calcium in group C was lower than that in group A [(1.89±0.11) vs. (2.02±0.16) mmol/L, t=3.24, P=0.002] or group B [(1.89±0.11) vs. (2.01±0.15) mmol/L, t=2.72, P=0.010], with no significant difference in the mean levels of PTH or serum calcium between group A and group B (t=0.54, 0.29, respectively, both P>0.05). The incidences of permanent hypoparathyroidism/persistent hypocalcemia were 3.2% (1/31) in group A, 5.3% (1/19) in group B and 21.7% (5/23) in group C, and the incidence of group C was significantly higher than that (4%, 2/50) of both group A and group B (χ(2)=5.251, P=0.022). Conclusion: The postoperative parathyroid function and serum calcium level have different degrees of change and they are significantly associated with thyroidectomy approaches, the protection of parathyroid by oral endoscopic thyroidectomy and routine thyroidectomy can achieve the same effect, and is better than that of transthoracic thyroidectomy.