The primary disadvantage of conventional plastic biliary stents is their short patency
rate [1], as they are prone to biofilm buildup within the central lumen of the stent, resulting
in impaired bile flow [2]. The wing stent (ViaDuct; GI Supply, Camp Hill, Pennsylvania, USA) was engineered
to overcome this problem ([Fig. 1]).
Fig. 1 Wing stent (10 Fr, 12 cm) with soft pliable retention flaps and a radiopaque black
marker for accurate placement. The stent channels fluid along its winged perimeter,
which may increase its patency rates.
The wing stent is a lumenless stent in which bile is channeled along the exterior
winged grooves, theoretically reducing the risk of occlusion ([Fig. 1]) [3]
[4]. Computer modeling studies have shown that the wing stent offers a larger surface
area for flow, a higher flow velocity, and increased flow rates compared with conventional
plastic stents. A pilot study reported the successful use of the wing stent for endoscopic
biliary drainage in five patients with malignant biliary obstruction, all of whom
experienced a significant decline in bilirubin at 2 weeks and resolution of biliary
dilation by radiologic imaging [3].
The endoscopic placement of multiple stents over time for patients with benign biliary
strictures has been shown to be an effective therapy for stricture resolution [5]. The placement of multiple stents can be technically challenging for a number of
reasons, including failure of repeat biliary cannulation after the first stent insertion.
This can occur if a small biliary sphincterotomy was performed and/or the positioning
of the first stent prevents the necessary angulation of the biliary cannula or sphincterotome.
This problem can be overcome by initially placing a 7-Fr or 10-Fr wing stent into
position using a push catheter until the radiopaque black marker at the distal end
of the stent is visualized at the biliary orifice. Subsequently, rapid repeat biliary
cannulation is achieved by advancing a guidewire into the groove between two wings
of the in-situ wing stent and into the proximal bile duct. A conventional plastic
stent is then placed over the wire and advanced into the bile duct. Additional stents
can then be placed in similar manner ([Fig. 2], [Video 1]).
Fig. 2 a After the wing stent is placed in the bile duct, the wire is placed in the channel
between two wings of the stent. b The wire is then advanced into the bile duct. c A second stent can subsequently be placed without difficulty over the wire in standard
fashion.
Video
1 After the wing stent is placed in the bile duct, the wire is placed in the channel
between two wings of the stent and advanced into the bile duct. A second stent can
subsequently be placed over the wire in the standard fashion.
Competing interests: None
Endoscopy_UCTN_Code_TTT_1AR_2AZ
