Thyroidectomy improves tracheal anatomy and airflow in patients with nodular goiter. A prospective cohort study

Background: A large goiter may cause compression of the trachea and lead to respiratory insufficiency. We aimed at investigating the effects of thyroidectomy on tracheal anatomy and airflow in patients with benign nodular goiter, employing a prospective observational study. Methods: Magnetic resonance images (MRI) of the neck and respiratory flow-volume curves, including both in- and expiration, were performed prior to and six months following surgery. The evaluated tracheal dimensions included the smallest cross-sectional area of the trachea (SCAT), tracheal narrowing, and tracheal deviation. Effect sizes (ES) were calculated as mean change divided by standard deviation at baseline. ES of 0.2-0.5 were defined as small, 0.5-0.8 as moderate, and values >0.8 as large.Results: Sixty-five patients completed all examinations. Median goiter volume was 58 mL (range, 14-642 mL) before surgery with surgical removal of median 43 g (range, 8-607 mL). Six months post-surgery, tracheal narrowing and deviation were diminished by median 26% (ES=0.67), and 33% (ES=0.73), respectively, while SCAT increased by 17% (ES=0.61). Correspondingly, each 10% decrease in goiter volume resulted in an increase of 6.0% in SCAT (p<0.001), and a decrease of 1.0% in tracheal narrowing (p<0.001). Concomitantly, a small improvement was seen in forced inspiratory flow at 50% of forced vital capacity (FIF50%) (ES=0.32). Discussion: In patients with symptomatic benign nodular goiter, thyroidectomy leads to substantial improvement in tracheal compression, but only minor improvements in tracheal airflow. This information is pertinent when counselling patients before choice of treatment.