Loop formation can impede endoscope advancement, destabilize the tip, and cause pain. Strategies to mitigate looping include torque-based reduction maneuvers, variable stiffness shafts, and abdominal splinting. In some cases, these strategies are insufficient, and there is need for novel instruments. Loop formation is of particular concern in colonoscopy, but it can also impact performance of other endoscopic procedures such as enteroscopy and altered-anatomy ERCP. In this case series we demonstrate the utility of a novel rigidizing overtube (Pathfinder; Neptune Medical, Burlingame, Calif, USA) in colonoscopy and other endoscopic procedures where loop management is critical.

We describe our initial experience with the Pathfinder overtube in 29 patients. The overtube is 85 cm long and can accommodate a pediatric colonoscope. In its native state, the overtube is extremely flexible. Once the overtube is advanced to the desired location, application of a vacuum to the device causes the device to become 15 times stiffer. The endoscope can then be advanced through the overtube without loop formation in the region that the overtube traverses.

The overtube was used in 29 patients to assist with difficult procedures. Patients were predominantly men (n = 18; 62.1%), with a median age of 66 years (interquartile range, 57-72). One patient received an upper endoscopy (3.4%), 24 received colonoscopy (82.8%), and 4 received enteroscopy (13.8%). The overtube was used in 12 procedures for incomplete colonoscopy (41.4%), 6 for depth (20.7%), and 11 for stability (37.9%). Colonoscopy was performed in the setting of screening (n = 3), surveillance given polyp history (n = 7), referrals for polyp removal (n = 10), workup of iron deficiency anemia (n = 2), and incomplete colonoscopy (n = 1). The lower endoscopy cases had a median cecal intubation time of 5 minutes (interquartile range, 4.25-7). Enteroscopy was performed in 4 patients: In one patient the distal 60 cm of the ileum was examined with a pediatric colonoscope to exclude ileitis, in another the overtube was used to stabilize a 6-mm endoscope to traverse a tight Crohn’s ileocolonic stricture, in a third patient altered-anatomy ERCP was performed using an enteroscope through the overtube to reach a hepaticojejunostomy, and in the final patient upper enteroscopy was performed and the mid-jejunum was reached. We present 4 cases that demonstrate the use of the overtube. There were no adverse events.

Initial experience with a novel rigidizing overtube suggests that this tool can be useful in colonoscopy and other endoscopic procedures affected by looping.