Volumetric Analysis is Useful for Predicting Use of Sternotomy During Retrosternal Thyroidectomy

Abstract

Surgical removal is the recommended treatment for retrosternal goitre. This can be successfully achieved through a cervical incision in most cases, however occasionally a thoracic approach is required. Being able to predict the need for sternotomy would improve logistical efficiency, saving time and money, and allow patients to be better informed preoperatively. The aim of this study was to determine whether analysing thyroid volume on preoperative CT scans could help predict the use of sternotomy. To the best of our knowledge this is the first study investigating this. A retrospective study was conducted on 64 patients who underwent thyroidectomy for retrosternal goitre at the Golden Jubilee National Hospital, Scotland, between 2012-2016. Patient demographic information and pathological reports were obtained from databases. Preoperative CT scans were used for volumetric analysis. The total volume, the volume inferior to the level of the sternal notch (intrathoracic volume), and the anteroposterior diameter of the thoracic inlet were measured. An index of relative goitre size was calculated by dividing intrathoracic volume by thoracic inlet diameter. Mann-Whitney U tests and Fisher's exact tests were used to analyse continuous and categorical variables respectively. Goitres were successfully removed by a cervical incision alone in 55 patients, while thoracic intervention was needed in 9 cases (13.3%). Intrathoracic volume (p=0.0091) and volumetric index (p=0.0033) were significantly larger in those requiring sternotomy. Total volume was not significantly different. All other variables measured were similar in both groups. Our results suggest that assessing intrathoracic volume of goitre is useful in predicting the need for sternotomy. However, it is not able to completely rule out thoracic intervention. The volumetric index is likely to be a better predictor than volume alone.