Combined stent-in-stent and side-by-side stenting for hilar cholangiocarcinoma using a novel braided and weaving metal stent

For hilar malignant biliary obstruction, bilateral self-expandable metal stent (SEMS) placement provides longer patency than unilateral drainage [1] [2]. Although recently developed fine-gauge delivery systems allow simultaneous side-by-side (SBS) placement, the partial stent-in-stent (SIS) method is sometimes preferred because of higher adverse event rates with SBS [3]. However, technical difficulty can be encountered with the SIS method, such as guidewire or stent delivery through the stent interstice [4]. Herein, we present a combined SIS and SBS technique using a novel SEMS with a combination of braided and weaving construction ([Video 1]).

Video 1 A novel self-expandable metal stent for drainage of hilar malignant biliary obstruction with a combination of stent-in-stent and side-by-side methods.

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A 69-year-old woman with unresectable hilar cholangiocarcinoma was referred to us, and endoscopic retrograde cholangiography revealed hilar biliary obstruction. After passing three guidewires to B2, B6, and B8, respectively ([Fig. 1]), two uncovered SEMSs (Niti-S M Biliary Stent, 8-mm-wide; Taewoong Medical Inc., Gimpo, Korea) ([Fig. 2]) were placed, first in an SIS fashion (from B6 to the duodenum first, followed by B8 to the duodenum) ([Fig. 3 a]) without difficulty. Initially, additional stent placement was attempted in an SIS fashion but guidewire passage through the two overlapped stents was not technically easy and thus, we decided to place the third SEMS in an SBS fashion over the guidewire, which had been already placed in B2 as a landmark. The delivery system was readily inserted to B2 without interference to or from the other two SEMS, and the third SEMS ([Fig. 3 b]) was successfully deployed in an SBS fashion from B2 to the duodenum. No procedure-related adverse events were observed.

Fig. 1 Cholangiogram delineating severe hilar biliary stricture due to cholangiocarcinoma. Guidewires were successfully passed to B2, B6, and B8, respectively. A percutaneous catheter, which was placed for cholecystitis during previous hospitalization, can also be seen.

Fig. 2 The Niti-S M Biliary Stent (Taewoong Medical Inc., Gimpo, Korea). The stent mesh is characterized by a braided and weaving construction with large flexible interstices, potentially facilitating passage of a guidewire to the contralateral bile duct. This stent also has characteristics of a 7.5-Fr delivery system. Because of these features, Niti-S M Biliary Stent can be used for both side-by-side and stent-in-stent placement.

Fig. 3 Fluoroscopic and endoscopic images. a Fluoroscopy showing two metal stents placed in a partial stent-in-stent fashion for B6 and B8. b Fluoroscopic and endoscopic views showing a metal stent placed alongside the metal stents in a side-by-side fashion.

Despite the superiority of bilateral over unilateral stenting for hilar malignant biliary obstruction, there is no standard technique – SIS or SBS. This novel SEMS with braided and weaving construction allows both SIS and SBS methods, and even its combination method [5] can be applied, as shown in this case.

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• References

• 1 Moon JH, Rerknimitr R, Kogure H. et al. Topic controversies in the endoscopic management of malignant hilar strictures using metal stent: side-by-side versus stent-in-stent techniques. J Hepatobiliary Pancreat Sci 2015; 22: 650-656
• 2 Lee TH, Kim TH, Moon JH. et al. Bilateral versus unilateral placement of metal stents for inoperable high-grade malignant hilar biliary strictures: a multicenter, prospective, randomized study (with video). Gastrointest Endosc 2017; 86: 817-827
• 3 Naitoh I, Hayashi K, Nakazawa T. et al. Side-by-side versus stent-in-stent deployment in bilateral endoscopic metal stenting for malignant hilar biliary obstruction. Dig Dis Sci 2012; 57: 3279-3285
• 4 Kogure H, Isayama H, Nakai Y. et al. High single-session success rate of endoscopic bilateral stent-in-stent placement with modified large cell Niti-S stents for malignant hilar biliary obstruction. Dig Endosc 2014; 26: 93-99
• 5 Inoue T, Ibusuki M, Kitano R. et al. A combined side-by-side and stent-in-stent method for triple metal stenting in patients with malignant hilar biliary obstruction. Dig Endosc 2019;