Reply to Moreels et al.

We appreciate Mouradides et al. for their valuable comments regarding our recent study that described the usefulness of short-type single-balloon enteroscope (short SBE)-assisted endoscopic retrograde cholangiopancreatography (ERCP) and potential factors affecting procedural failure [1]. It is our pleasure to share our opinion regarding their comments and to provide further insight into the role of passive bending in our recently published series.

As Mouradides et al. mentioned, we used three different models of a short SBE depending on the study period, and two of these (i. e. SIF-Y0004-V01 and SIF-Y0015) were equipped with passive bending and force transmission features.

Mouradides et al. reported one interesting case in their Letter. They attempted three SBE-assisted ERCPs in the same patient with long-limb Roux-en-Y gastric bypass, and only the ERCPs performed with the SBE equipped with a passive bending segment with force transmission were successful. We agree that, theoretically, a passive bending segment with force transmission may facilitate scope insertion in cases with sharp and difficult intestinal angulations, particularly in patients with long-limb Roux-en-Y reconstruction.

With regard to passive bending, previous studies have shown that a colonoscope with a passive bending function is useful after incomplete colonoscopy because of a sharp angulation [2] [3]. For balloon enteroscope-assisted ERCP, Shimatani et al. mentioned that the use of a short single-balloon enteroscope with a passive bending part may increase the enteroscopy success rate [4].

In our study, the absence of passive bending was not included in the potential factors affecting enteroscopy (P = 0.119) and procedural failure (P = 0.083). We performed subgroup analysis between groups in the presence or absence of Roux-en-Y reconstruction. The results showed that even in the Roux-en-Y reconstruction group, the absence of passive bending was not included in the potential factors affecting enteroscopy (P = 0.466) and procedural failure (P = 0.348). Similarly, Yamauchi et al. reported that a scope with a passive bending function may reduce the time required to reach the blind end; however, the rate of reaching the blind end was found to be equivalent to the rate achieved when using a single-balloon endoscope without a passive bending function [5]. These results may be due to the insufficient statistical power of the studies. In our study, although there was no significant difference between the two groups, the procedural success rate tended to be higher in the passive bending scope group. Therefore, the valuable role and advantages of a passive bending function should ideally be confirmed further by conducting a multicenter randomized controlled study.

• References

• 1 Yane K, Katanuma A, Maguchi H. et al. Short-type single-balloon enteroscope-assisted ERCP in postsurgical altered anatomy: potential factors affecting procedural failure. Endoscopy 2017; 49: 1-2
• 2 Mizukami T, Ogata H, Hibi T. “Passive-bending colonoscope” significantly improves cecal intubation in difficult cases. World J Gastroenterol 2012; 18: 4454-4456
• 3 Sato K, Shigiyama F, Ito S. et al. Colonoscopy using a small-caliber colonoscope with passive bending after incomplete colonoscopy due to sharp angulation or pain. Surg Endosc 2013; 27: 4171-4176
• 4 Shimatani M, Takaoka M, Ikeura T. et al. Evaluation of endoscopic retrograde cholangiopancreatography using a newly developed short-type single-balloon endoscope in patients with altered gastrointestinal anatomy. Dig Endosc 2014; 26 (Suppl. 02) 147-155
• 5 Yamauchi H, Kida M, Okuwaki K. et al. Passive-bending, short-type single-balloon enteroscope for endoscopic retrograde cholangiopancreatography in Roux-en-Y anastomosis patients. World J Gastroenterol 2015; 21: 1546-1553