Insertion of a duodenoscope can be challenging or even impossible in patients with altered anatomy, increasing the risk of complications. The side-viewing optics of the duodenoscope further complicate advancement through a distorted esophagus. However, this problem cannot always be resolved by advancing the duodenoscope over or alongside a guidewire, nor by attempting ERCP with a forward-viewing gastroscope. We present a case in which, after multiple unsuccessful attempts to introduce the duodenoscope in a patient with cholangitis, we used a single-use cholangioscope as a visual guide to facilitate safe passage of the duodenoscope into the esophagus, effectively converting the side-viewing optics into a forward-viewing approach. This technique enabled successful completion of ERCP and avoidance of procedure-related complications.

In cases of difficult duodenoscope insertion into the esophagus due to altered anatomy, the side-viewing optics of the duodenoscope can be temporarily converted into a forward-viewing orientation using a cholangioscope.  After performing diagnostic esophagoscopy with a standard gastroscope and confirming that no fixed stenosis was present to prevent passage of the scope, either a dual-operator “mother–baby” technique or a single-operator fiberoptic cholangioscope may be used to facilitate safe insertion. In our case, we used the dual-operator “mother–baby” technique with a single-use cholangioscope.Under gastroscopic visualization, a standard 0.035-inch guidewire was first advanced into the stomach. The gastroscope was then withdrawn, leaving the guidewire in place. Next, a single-use dual-operator cholangioscope was introduced through the duodenoscope’s working channel. The distal ends of both scopes were aligned and jointly advanced over the guidewire into the esophagus, providing direct forward-viewing visualization. Once the duodenoscope was positioned correctly within the esophagus, both the cholangioscope and the guidewire were removed, and ERCP was subsequently completed without complications.

A 95-year-old patient with a history of Bechterew’s disease presented in septic shock due to Grade III acute cholangitis and was referred for urgent ERCP. The procedure was performed under conscious sedation in a prone position.

Initial attempts to introduce a standard side-viewing duodenoscope through the upper esophageal sphincter were unsuccessful. Switching to a gastroscope also proved difficult, though insertion was achieved after repositioning the patient to the left lateral position. Endoscopic inspection revealed a normal-appearing upper esophageal sphincter, but withdrawal of the gastroscope showed a distorted pharyngeal–esophageal axis, likely related to long-standing Bechterew’s disease.

 A 0.035-inch guidewire was advanced into the stomach and the gastroscope was withdrawn, leaving the guidewire in place. Attempts to advance the duodenoscope over the guidewire failed. To overcome this, a single-use dual-operator cholangioscope was introduced through the duodenoscope’s working channel. The distal ends of both scopes were aligned and safely advanced over the guidewire into the esophagus, providing forward-viewing visualization. Once the duodenoscope was positioned in the esophagus, both the cholangioscope and guidewire were removed, and ERCP was successfully completed.

In cases of altered anatomy of the pharynx or upper esophageal sphincter, standard duodenoscope insertion may be challenging. The main limitation lies in the side-viewing optics, which prevents direct visualization of the upper esophageal sphincter and increases the risk of injury during insertion. By temporarily converting the side-viewing duodenoscope into a forward-viewing system using a cholangioscope, safe and controlled entry into the esophagus can be achieved. This simple modification expands both the feasibility of ERCP and the potential novel use of cholangioscope in anatomically challenging conditions. Future experience and broader application of this technique could improve procedural safety and accessibility in similar anatomically demanding cases.