Materials and Methods
Our patient initially presented at 7 years of age with shortness of breath with exertion and noisy breathing at rest. Her exertional symptoms were progressive, and she experienced prolonged recovery from upper respiratory infections. Subsequently she was no longer getting relief from bronchodilators that she had used up to that point. A chest x-ray revealed a right sided aortic arch. A computerized tomography (CT) scan demonstrated a double aortic arch with atretic distal left arch with no Kommerell’s diverticulum. Bronchoscopy was performed which revealed 40% narrowing at the mid-trachea. Echocardiography examination provided a normal intra cardiac anatomy. Thoracoscopic division of the atretic left arch and left ligamentum was performed without incident and the patient recovered uneventfully.
Two years later the patient continued to have residual symptoms of shortness of breath with any exercise, including climbing a single flight of stairs. Her breathing at rest remained noisy, and she became breathless with talking for extended periods of time. Treatment with albuterol and fluticasone inhalers did not alleviate symptoms. An exercise study was performed to better delineate the mechanism of her symptoms which was read as consistent with mild obstruction. Both during her exercise testing and when performing spirometry at rest she elicited normal inspiratory loops, however her expiratory loop was flattened suggesting dynamic airway obstruction (Figure 1). Bronchoscopy was repeated which revealed normal vocal cord mobility, but compression at the lateral rightward aspect of the trachea (Figure 2). A CT scan was repeated to better delineate her anatomy.
Her case was discussed in our multidisciplinary congenital cardiac/thoracic conference where her repeat CT scan was reviewed. A rightward to leftward course of her aorta above the level of the carina was consistent with the diagnosis of circumflex aorta.
A discussion with the family over the phone where a description of the relevant anatomy and plan for treatment. Optimal understanding of the anatomy and its surgical solution was difficult to achieve. A 3D model of her anatomy using blood and air volumes was made using Materialise® Mimics and 3-matic software (Leuven Belgium) and was printed on a an Ultimaker® 3 Extended printer using polylactic acid (PLA) filament. Figure 3 shows the resultant 3D model, created from her CT scan images. The post-procedural model was used preoperatively for the second operation to help describe the symptoms and the complex operation needed to provide relief of external compression of the trachea (1). This 3D model made conversation from this point on in the patient’s care clear in both objectives and planning for outcomes.