Endovascular steerable and endobronchial precurved guiding sheaths for transbronchial needle delivery under augmented fluoroscopy and cone beam CT image guidance

Background: Endobronchial navigation is performed in a variety of ways, none of which are meeting all the clinicians' needs required to reach diagnostic success in every patient. We sought to characterize precurved and steerable guiding sheaths (GS) in endobronchial targeting for lung biopsy using cone beam computed tomography (CBCT) based augmented fluoroscopy (AF) image guidance. Methods: Four precurved GS (EdgeTM 45, 90, 180, 180EW, Medtronic) and two steerable GS [6.5 F Destino Twist (DT), Oscor; 6 F Morph, BioCardia] were evaluated alone and in combination with an electromagnetic tracking (EM) guide and biopsy needles in three experimental phases: (I) bench model to assess GS deflection and perform biopsy simulations; (II) ex vivo swine lung comparing 2 steerable and 2 precurved GS; and (III) in vivo male swine lung to deliver a needle (n=2 swine) or to deliver a fiducial marker (n=2 swine) using 2 steerable GS. Ex vivo and in vivo image guidance was performed with either commercial or prototype AF image guidance software (Philips) based on either prior CT or procedural CBCT. Primary outcomes were GS delivery angle (theta GS) and needle delivery angle (theta N) in bench evaluation and needle delivery error (mm) (mean +/- se) for ex vivo and in vivo studies. Results: The steerable DT had the largest range of GS delivery angles (theta N: 0-114 degrees) with either the 21 G or 19 G biopsy needle in the bench model. In ex vivo swine lung, needle delivery errors were 8.7 +/- 0.9 mm (precurved Edge 90), 5.4 +/- 1.9 mm (precurved Edge 180), 4.7 +/- 1.2 mm (steerable DT), and 5.6 +/- 2.4 mm (steerable Morph). In vivo, the needle delivery errors for the steerable GS were 6.0 +/- 1.0 mm (DT) and 15 +/- 7.0 mm (Morph). In vivo marker coil delivery was successful for both the steerable DT and morph GS. A case report demonstrated successful needle biopsy with the steerable DT. Conclusions: Endobronchial needle delivery with AF guidance is feasible without a bronchoscope with steerable GS providing comparable or improved accuracy compared to precurved GS.