The Usefulness of Endobronchial Ultrasonography-guided Transbronchial Needle Aspiration at the Lobar, Segmental, or Subsegmental Bronchus Smaller Than a Convex-type Bronchoscope

Endobronchial ultrasonography-guided transbronchial needle aspiration (EBUS-TBNA) is a standard procedure for approaching the lesion adjacent to extrapulmonary bronchus. We started to use wedge insertion of a convex endobronchial ultrasound bronchoscope into bronchi narrower than the diameter of the bronchoscope itself to perform EBUS-TBNA. Our objective was to investigate the bronchus in which EBUS-TBNA was possible and safe. Methods: In this prospective study, we examined 15 lesions that were adjacent to lobar, segmental, or sub-segmental bronchi narrower than the 6.9mm external diameter of the convex scope. The cross-sectional area and maximum, minimum, and mean internal diameters of the airway lumen adjacent to the lesion were calculated using the measurement software. We investigated the airway branch in which EBUS-TBNA was possible, the narrowest airway diameter adjacent to the lesion for which insertion and diagnosis could be performed, the feasibility of puncture, and techniques for ensuring procedural success. Results: The mean cross-sectional area of the lumen for the 13 lesions that could be punctured was >= 15.9mm(2) and the mean internal diameter was >= 4.5mm. Cytologic or histologic diagnosis by EBUS-TBNA was possible in 11 of the 15 cases. In 2 of the 4 undiagnosed lesions, the mean internal diameter was < 4.5mm, and the convex scope was unable to reach the lesion. There was no occurrence of complications in any case. Conclusions: EBUS-TBNA can be performed by inserting a 6.9 mm EBUS bronchoscope into airways with a mean diameter >= 4.5 mm as measured on computed tomography before bronchoscopy.