Does the diameter of the thoracic inlet influence the formation of retrosternal goiter?

Abstract

Introduction: Retrosternal goiter (RSG) can be defined as greater than 50% of the thyroid volume within the thorax. RSG is present in 2-26% of all thyroidectomies, depending on the defining criteria. Objective: Find an association between diameter of the thoracic inlet (TI) and RSG to determine whether the TI would function as a natural anatomical barrier to prevent the passage of the goiters to the thoracic cavity. Methods: A retrospective study was conducted with patients submitted to total thyroidectomy, with goiter greater than 50 cm 3 , who underwent computed tomography (CT) preoperatively to measure the TI volume. The values obtained from each continuous variable of parametric distribution were organized and described as mean and standard deviation. The distributions were defined as non-parametric by the Kolmogorov-Smirnov test. The Mann-Whitney test was used to compare two sample populations. Results: A total of 173 patients submitted to total thyroidectomy were evaluated, and 54 patients met the inclusion criteria of the study. 85.2% were female, with a mean age of 57 years. The mean diameter of the TI was 5679 mm 2 . 42% of the patients presented some degree of RSG. The distance below the TI ranged from 0.2 to 5 cm. Conclusion: No significant association was found between diameter of the thoracic inlet and retrosternal goiter, demonstrating that RSG can be present regardless of the TI diameter. Statistically significant association was observed between patients with larger thyroid volume and the likelihood of this tissue to extend to the thoracic cavity.