TG and thyroid crisis: Following pre-operative treatment, there was a mean percentage reduction of fT4 and fT3 by 52.6 ± 8.2% and 68.1 ± 9.3% respectively in the included studies (Table 3) and there were no events of perioperative thyroid storm reported despite a lack of normalization of thyroid hormone levels in some patients prior to thyroidectomy.