When the anastomosis is not identied during insertion, continued advancement may lead the enteroscope in the wrong direction (e.g., efferent loop instead of affer­ent loop). If the enteroscope has advanced approximately 120–140cm and the tip is observed in the central abdomen or pelvis on uoroscopy, this often indicates that the scope has entered the efferent loop. In that situation, the enteroscope should be slowly withdrawn to nd the anastomosis. If the anastomosis or suture clips are not directly visible, clues such as the disappearance of Kerckring’s folds, reverse peri­stalsis, or the presence of bile are useful to identify the anastomosis. A sudden wid­ening of the lumen may also indicate proximity to the anastomosis, and thus this area should be carefully examined to gure out surgical scars or dual lumens (Table5.2, Fig.5.3) [1].

Bowel perforation is the most serious complication, occurring mainly at the bil­iary-enteric anastomosis or near the duodenal papilla. It is recommended to perform BAE at least 2 weeks after Roux-en-Y anastomosis to avoid anastomotic injury. In most cases where BAE is performed to evaluate pancreaticobiliary problems rather than for bleeding, several months or years have passed since the surgery, so the risk of anastomotic site injury is generally low. However, most ERCP procedures are performed at or near to the blind end of the afferent loop after stabilizing the scope position by the inated overtube balloon. So, excessive or prolonged gas insufa­tion in that situation can rapidly increase the intraluminal pressure of the blind loop, potentially causing air leakage from the biliary-enteric anastomosis and papillary sphincterotomy into the peritoneal or retroperitoneal cavity. In addition to perfora­tion, bleeding, cholangitis, or pancreatitis may occur after ERCP, though these are usually mild and resolve with conservative treatment. Mucosal injury and subse­quent bleeding in the stomach or afferent loop due to mechanical pressure from BAE have also been reported and can be managed with conservative treatment.

In a recent study of 122 patients with incomplete colonoscopy, balloon-assisted small bowel enteroscopy achieved a cecal intubation rate of 92.6%, with failure rates of 8.3% (1 of 12) for single-balloon and 7.3% (8 of 110) for double-balloon enteroscopy. Success rates varied based on the cause of the initial failure: 84.6% in patients with a history of abdominal surgery, 96.3% in those with abdominal dis­comfort, and 90.7% in those with angulation or diverticular disease, highlighting the effectiveness of balloon-assisted enteroscopy in challenging cases [10]. A com­parison between single-balloon and double-balloon enteroscopy showed cecal intu­bation rates of 100% (26 of 26) and 93% (25 of 27), with no signicant difference between the two methods [11].

Both auxiliary endoscopic devices have limited research regarding their use in patients with incomplete colonoscopy [7, 15].