Knock-knock-knockin' on bile duct's door: the "tip-of-the-biopsy-forceps technique" - probing the route during freehand-intubated direct cholangioscopy.

Direct cholangioscopy is a highly innovative field in pancreaticobiliary endoscopy; however, its wider dissemination is hampered by high technical procedural demands and/or the need for specialized equipment. Much technological progress is underway including clinical evaluation of double-bending cholangioscopes and next-generation anchoring balloons [1] [2]. By contrast, freehand intubation for direct cholangioscopy has largely been discredited by expert opinion, even though high rates of technical success have been published in single series and individual clinical reports [3]. Here, I report on a novel, easy-to-implement technique to facilitate freehand intubation, called the “tip-of-the-biopsyforceps technique” (▶Video1). ▶Fig. 1 a shows a papilla at the rim (2 o’clock position) of a periampullary diverticulum after medium-incision papillotomy, with an air bubble highlighting its entrance (Olympus XP-160, outer diameter 5.9mm; Olympus, Hamburg, Germany). In successful freehand direct cholangioscopy, it is important to attain close tissue contact during intubation; however, this creates a higher risk of obscured visual orientation (“red out”) (▶Fig. 1b). Similar to cap assistance in other endoscopy applications, gentle probing with the tip of a biopsy forceps achieves minimal distance from the mucosa, resulting in anatomic reorientation in an acutely angulated prepapillary bile duct (▶Fig. 1 c; asterisk shows the tip of the forceps), which is firmly intubated in a stable scope position after adjusting the axis (▶Fig. 1d). The presented novel rescue maneuver for difficult freehand intubation for direct cholangioscopy may provide valuable assistance in regaining orientation, while properly maintaining close contact with the papillary mucosa.