A Flexible 3D Printed Template to Assist with Physician Modified Endografts for FEVAR

Abstract

Fenestrated endovascular aneurysm repair (FEVAR) for juxtarenal AAAs is limited by cost and the availability of custom made endografts, in addition to technical complexity. Rigid 3D printed anatomical models of the visceral aorta have been used to supplement fenestration placement and as an alternative to conventional centreline based planning; however, these do not simulate the geometric interaction between wires, delivery system, endograft, and aortic tissue. We present a novel translucent, flexible 3D printed template which simulates aortic conformation. Flexible templates better approximate the straightening of native aorta when endografts are deployed and may assist fenestration planning to reduce the risk of splanchnic vessel misalignment. The visceral segment of a juxtarenal AAA was modelled from a computed tomography aortogram, with the splanchnic vessels cropped at their origin to allow fenestrations to be marked (Fig. 1). A Projet 3500 3D printer (3D Systems Corporation, Rock Hill, USA; cost €70 000) was used to print the flexible template. The 3D printed templates are sterilised using ethylene oxide or autoclave techniques. Lunderquist wire cannulation was performed with deployment of an off the shelf Endurant endograft (Medtronic Inc., Minnesota, USA). Splanchnic branch ostia were marked with a sterile pen (Fig. 2). The material was translucent to avoid positioning the fenestrations over struts.Figure 2Fenestrations are planned by marking through the template with a sterile marking pen.View Large Image Figure ViewerDownload Hi-res image Download (PPT) The template was 3D printed in flexible resin (Visijet CE-NT, 3D Systems) on its first attempt over 24 h, costing €95 in materials. This presents a significant time advantage over commercial fenestrated endografts, which require a minimum of one month lead time. In addition, 3D printed template assisted physician modified stent grafts result in substantial cost savings when compared with commercial alternatives. Flexible models may also assist with validation of commercial FEVAR graft construction. 3D printed templates to assist with the back table fenestration of standard commercial endografts are a promising frontier for FEVAR. We report the first instance of a flexible template which mitigates some limitations surrounding templates 3D printed with rigid materials. None.