Diagnostic Accuracy Study of CT Scan in Predicting the Need for Sternotomy in Management of Substernal Goiters

Abstract

objective: To find a new predictor of sternotomy with thyroid gland measurements in CT scan. Materials and methods: We performed a retrospective review of our endocrine surgery database between January 2012 and October 2017. We identified 123 patients treated for substernal goiter, 7 required an extra-cervical approach, and 116 a cervical one. The measurement of thyroid gland craniocaudal length, larger diameter of mediastinal component, and the diameter of thoracic inlet were performed in all patients with substernal goiter. ROC analysis was performed to determine craniocaudal length and mediastinal thyroid mass diameter cutoff value, which significantly predict the need of an extra-cervical approach for substernal goiter. Results: The craniocaudal length of thyroid mass below thoracic inlet ≥34.5 mm and the diameter of mediastinal component ≥53.5 mm were significantly associated with the need of an extra-cervical approach ( p = 0.005 and p = 0.015, respectively). We also analyzed the ratio between mediastinal component diameter and thoracic inlet diameter and the ROC analysis of this ratio identified ≥1.24 as the cutoff value with maximum accuracy. A ratio ≥1.24 was significantly associated with the need of sternotomy ( p = 0.03) with a likelihood ratio of 9.09 (IC 4.32-19.51). Conclusion: The ratio between mediastinal component diameter and thoracic inlet ≥1.24 was a significant determining factor for sternotomy. Clinical significance: The ratio we suggest based in CT scan measurements allows the identification of patients who may need sternotomy, permitting referral patients to another hospital with thoracic surgeons and prior preparation of the surgical team. Furthermore, these measurements can be obtained by a trained head and neck surgeon.