Retrospective Cohort Study
Copyright ©The Author(s) 2020. Published by Baishideng Publishing Group Inc. All rights reserved.
World J Gastrointest Surg. Apr 27, 2020; 12(4): 138-148
Published online Apr 27, 2020. doi: 10.4240/wjgs.v12.i4.138
Newly developed self-expandable Niti-S MD colonic metal stent for malignant colonic obstruction
Yuki Miyasako, Toshio Kuwai, Sauid Ishaq, Kanae Tao, Hirona Konishi, Ryoichi Miura, Yuki Sumida, Kazutaka Kuroki, Yuzuru Tamaru, Ryusaku Kusunoki, Atsushi Yamaguchi, Hirotaka Kouno, Hiroshi Kohno
Yuki Miyasako, Toshio Kuwai, Kanae Tao, Hirona Konishi, Ryoichi Miura, Yuki Sumida, Kazutaka Kuroki, Yuzuru Tamaru, Ryusaku Kusunoki, Atsushi Yamaguchi, Hirotaka Kouno, Hiroshi Kohno, Department of Gastroenterology, National Hospital Organization, Kure Medical Center and Chugoku Cancer Center, Kure 737-0023, Japan
Sauid Ishaq, Gastroenterology Department, Russells Hall Hospital, Birmingham City University, Birmingham B17 9BE, United Kingdom
Sauid Ishaq, St George’s University, University Centre Grenada, West Indies, Grenada
Author contributions: Miyasako Y drafted the manuscript, collected and interpreted data, planned the study, and approved the final draft submitted; Kuwai T drafted the manuscript, planned and conducted the study, interpreted data, and approved the final draft submitted; Ishaq S drafted the manuscript, conducted the study, and approved the final draft submitted; Tao K, Konishi H, Miura R, Sumida Y, Kuroki K, Tamaru Y, Kusunoki R, Yamaguchi A, Kouno H, and Kohno H collected data and approved the final draft submitted.
Institutional review board statement: The study was approved by the Institutional Review Board Ethics Committee of the National Hospital Organization Kure Medical Center and Chugoku Cancer Center.
Informed consent statement: All participants provided informed consent to the procedure and data collection.
Conflict-of-interest statement: There are no conflicts of interest to declare.
Data sharing statement: No additional data are available.
STROBE statement: The authors have read the STROBE Statement-checklist of items, and the manuscript was prepared and revised according to the STROBE Statement-checklist of items.
Open-Access: This article is an open-access article that was selected by an in-house editor and fully peer-reviewed by external reviewers. It is distributed in accordance with the Creative Commons Attribution NonCommercial (CC BY-NC 4.0) license, which permits others to distribute, remix, adapt, build upon this work non-commercially, and license their derivative works on different terms, provided the original work is properly cited and the use is non-commercial. See: http://creativecommons.org/licenses/by-nc/4.0/
Corresponding author: Toshio Kuwai, MD, PhD, Chief Doctor, Department of Gastroenterology, National Hospital Organization, Kure Medical Center and Chugoku Cancer Center, 3-1 Aoyamacho, Kure 737-0023, Japan. kuwai.toshio.ur@mail.hosp.go.jp
Received: December 21, 2019
Peer-review started: December 21, 2019
First decision: January 15, 2020
Revised: January 21, 2020
Accepted: March 25, 2020
Article in press: March 25, 2020
Published online: April 27, 2020
Processing time: 123 Days and 19.5 Hours
Abstract
BACKGROUND

Colonic stents are increasingly used to treat acute malignant colonic obstructions. The WallFlex and Niti-S D type stents are the commonly used self-expandable metallic stents available in Japan since 2012. WallFlex stent has a risk of stent-related perforation because of its axial force, while the Niti-S D type stent has a risk of obstructive colitis because of its weaker radial force. Niti-S MD type stents not only overcome these limitations but also permit delivery through highly flexible-tipped smaller-caliber colonoscopes.

AIM

To compare the efficacy and safety of the newly developed Niti-S MD type colonic stents.

METHODS

This single-center retrospective observational study included 110 patients with endoscopic self-expandable metallic stents placed between November 2011 and December 2018: WallFlex (Group W, n = 37), Niti-S D type (Group N, n = 53), and Niti-S MD type (Group MD, n = 20). The primary outcome was clinical success, defined as a resolution of obstructive colonic symptoms, confirmed by clinical and radiological assessment within 48 h. The secondary outcome was technical success, defined as accurate stent placement with adequate stricture coverage on the first attempt without complications.

RESULTS

The technical success rate was 100% in Groups W, N, and MD, and the overall clinical success rate was 89.2% (33/37), 96.2% (51/53), and 100% (20/20) in Groups W, N, and MD, respectively. Early adverse events included pain (3/37, 8.1%), poor expansion (1/37, 2.7%), and fever (1/37, 2.6%) in Group W and perforation due to obstructive colitis (2/53, 3.8%) in Group N (likely due to poor expansion). Late adverse events (after 7 d) included stent-related perforations (4/36, 11.1%) and stent occlusion (1/36, 2.8%) in Group W and stent occlusion (2/51, 3.9%) in Group N. The stent-related perforation rate in Group W was significantly higher than that in Group N (P < 0.05). No adverse event was observed in Group MD.

CONCLUSION

In our early and limited experience, the newly developed Niti-S MD type colonic stent was effective and safe for treating acute malignant colonic obstruction.

Keywords: Colonic stenting; New endoscopic colonic stent; Malignant colonic obstruction; Niti-S; WallFlex

Core tip: We developed a new self-expandable metallic stent, the Niti-S MD colonic stent (with a diameter of 22 mm), that can be deployed using the 9-Fr delivery system. The stent not only increased the radial force while maintaining the stent structure and low axial force but also permitted delivery through highly flexible-tipped smaller-caliber colonoscope with a working channel of 3.2 mm. In this study, the technical and clinical success rate of the Niti-S MD type was 100%, and its perforation rate was 0%. It was safe and effective for treating acute malignant colonic obstruction.