Data Extraction
Two coauthors (Yujie Li and X.Z.) independently selected studies for inclusion and exclusion and reached consensus when they did not agree initially. The following variables were recorded: authors, journal and year of publication, number of patients, age, transient RLN palsy, permanent RLN palsy, transient hypoparathyroidism, permanent hypoparathyroidism and recurrence. If necessary, the corresponding authors of the studies were contacted to obtain supplementary information.