Tracheal intubation in a patient with undetectable tracheal narrowing on chest radiography.

We report here a 59-year-old man with a saber-sheath tracheal narrowing who was scheduled to undergo pharyngeal tumor resection under general anesthesia. The tracheal narrowing was not clearly detected by chest radiography during the preoperative examination, but it was visible on axial computed tomography (CT) images taken earlier for diagnostic purposes. Following fiber optic examination of the narrowed segment with the patient under anesthesia, the tube was inserted into the trachea using an Airway Scope. The tube was deliberately advanced into the trachea and was able to pass through the stenosis without any resistance. On postoperative radiological analysis, three-dimensional reconstruction of the trachea and virtual bronchoscopic images revealed a saber-sheath type tracheomalacia located from below the cricoid cartilage to the carina. The membranous wall had a normal width. This case indicates that chest radiographs may occasionally be inadequate for evaluating asymptomatic patients with tracheomalacia. If CT images have been taken for diagnostic purposes, they should be examined together with the chest radiograph. Digital chest radiography with edge enhancement may become a useful tool in the preoperative detection and evaluation of undetectable tracheal narrowing on conventional chest films.