A 70-year-old man was scheduled for a left video-assisted thoracoscopic surgery. No large airway anomaly was reported on the preoperative computed tomography (CT) scan. After standard uneventful induction, the patient was intubated with a single lumen endotracheal tube (SLT). Fiberoptic bronchoscopy (FOB; Olympus America Inc., Center Valley, PA, USA) was used to aid placement of a 7F Uniblocker (Fuji Systems Corp., Fukushima, Japan) inside the left mainstem bronchus (LMB) and revealed an odd configuration of central airways [Figure 1A]. The initial diagnosis was the inadvertent placement of the SLT in the right mainstem bronchus (RMB). However, after confirming the depth of the tube to be 21 cm and no change in the appearance of the tracheal anatomy on withdrawing the SLT several centimeters, it was realized that the SLT was indeed in the trachea.
The FOB was advanced into the rightmost bronchus, which showed two segmental bronchi. FOB of the middle lumen showed an absence of the RUL bronchus, instead appearing to bifurcate into the right lower and middle lobes similar to the bronchus intermedius in normal patients. The leftmost lumen had the same anatomy as a normal left bronchus. After a thorough assessment of the airway anatomy, diagnosis of a low-riding tracheal bronchus (TB) versus tracheal trifurcation was made. To isolate the left lung, the bronchial blocker (BB) was placed in the leftmost lumen, and the surgery was accomplished uneventfully. After the surgery, our attempts to look for the elusive TB in the preoperative axial CT scan images and chest radiograph were not successful. Only after a radiologist performed a minimum intensity projection of coronal reconstruction, were we able to identify the TB that was missed in the preoperative reporting [Figure 1B].