Jugaar| Volume 61, ISSUE 1, P157, January 2021

Download started.


Flat Spring to Ensure an Elastic and Compliant Branch Connection Between Two Stents

  • Nabil Chakfe
    Corresponding author. Department of Vascular Surgery and Kidney Transplant, Nouvel Hôpital Civil 1, place de l’Hôpital, 67091, Strasbourg, France.
    Department of Vascular Surgery and Kidney Transplant, University Hospital of Strasbourg, France

    Groupe Européen de Recherche sur les Prothèses appliquées à la Chirurgie Vasculaire (GEPROVAS), Strasbourg, France
    Search for articles by this author
  • Philippe Nicolini
    Groupe Européen de Recherche sur les Prothèses appliquées à la Chirurgie Vasculaire (GEPROVAS), Strasbourg, France

    Clinique du Parc, Lyon, France
    Search for articles by this author
  • David Contassot
    IDNEST Medical, Strasbourg, France
    Search for articles by this author
Open ArchivePublished:September 29, 2020DOI:


      Connecting large stents together is currently performed in two ways. The first is by overlapping, inserting a larger stent into a smaller one to obtain fixation through the radial force of the inner stent and friction between them. The second consists of laterally inserting a balloon expandable stent through a reinforced window to get fixation by plastic deformation of the stent inside a non-deformable aperture. These two approaches lead to stent protrusion through the window, or at least a vulnerable overlap zone. These connections are stiff and may predispose to late disconnection. This paper describes an innovative technology that ensures an elastic and adaptable perpendicular connection between two stents.


      The technology proposed here is for reconstruction of the ilio-caval confluence. The mother iliocaval stent is a laser cut nitinol conical stent that includes a window constructed as a specific braided elliptical nitinol wire, acting as a flat spring (Figure 1, Figure 2A ). The branch is a braided nitinol wire stent with a special proximal design that opens in a “floral” configuration, followed by a groove and a flare (Fig. 1B). The caval part of the mother stent is first deployed; the window is cannulated to allow insertion of the branch delivery system (Fig. 2A). The branch is delivered in three steps: the proximal “flower” inside the mother stent, the flare outside, and then the remaining branch to lock the flat spring against the groove. After complete delivery of the branch stent, the window establishes an equilibrated connection using the elastic forces applied by both the branch stent and the flat spring (Figure 1, Figure 2B).
      Figure 1
      Figure 1(A) The laser cut nitinol iliocaval stent with the window including the flat spring and the dedicated iliac branch. (B) The iliac branch is connected to the mother stent.
      Figure 2
      Figure 2Connection between the iliocaval stent and the iliac branch. (A) The flat spring is in a relaxed state. (B) Once the groove is open in the window, the flat spring is now compressing the groove.


      Prototypes have been constructed for testing to obtain a CE mark and further trialling. The next step of this technology is the application in covered stents for branched devices in the aortic arch.


      Commenting Guidelines

      To submit a comment for a journal article, please use the space above and note the following:

      • We will review submitted comments as soon as possible, striving for within two business days.
      • This forum is intended for constructive dialogue. Comments that are commercial or promotional in nature, pertain to specific medical cases, are not relevant to the article for which they have been submitted, or are otherwise inappropriate will not be posted.
      • We require that commenters identify themselves with names and affiliations.
      • Comments must be in compliance with our Terms & Conditions.
      • Comments are not peer-reviewed.