Working with Phillips Plastics, Medtronic has developed a new delivery system
for AAA ("abdominal aortic aneurysm") endovascular surgery to deploy stent
grafts through a patient's arteries. The delivery system also provides a
new platform for Medtronic Vascular's endovascular product lines that will be
fully implemented after completion of all clinical trials and gaining approvals
in the U.S. and Europe.
The Xcelerant delivery system provides doctors an ergonomic tool for
precisely deploying stent grafts. A unique gear reduction system in the
handle of the delivery system and a release that disengages the gearing provides
a convenient, ergonomic method for doctors to use slow, controlled or rapid
deployment of the stent material.
The Xcelerant system is designed for volume manufacturing, and the handheld
unit snaps together to simplify the final assembly steps. The design
eliminates all mechanical fasteners, minimizes gluing operations, and uses
overmolded plastic parts to create a strong industrial design.
Designed for Manufacturing
Medtronic Vascular chose to outsource a range
of services for this project including industrial design, CAD design, design for
manufacturability, SLA, rapid tooling, mold development, qualification and
assembly. Phillips Plastics (www.phillipsplastics.com)
collaborated on the design and worked through details of mold development,
qualification, and completion of finished assemblies.
design allows customization to accommodate different anatomies and is suited for
a broad range of patients. The self-expanding, thin-wall polyester graft
material, supported by diamond-shaped elements, supplies high radial force for
reliable, secure sealing without barbs, hooks, or balloons. Markers on the
stent graft material aid in accurate stent graft placement.
Xcelerant Delivery System
The Xcelerant delivery system has a nose cone
with a long, tapered shape for easier arterial access. The soft, compliant
tapered tip increases flexibility for negotiating differing anatomies, and a
lubricious coating on the inner wall of the graft cover helps reduce deployment
forces and facilitates deployment of the stent grafts. The deployment
handle allows precise, controlled withdrawal of the stent graft cover and
features a smooth, intuitive motion.
"A key advantage of Xcelerant delivery system is that it offers a disposable
handle," says Scott Doig, Product Development Manager responsible for the
Xcelerant program at Medtronic. "Our current AneuRx product has a reusable
handle that has to be snapped on, and the user must autoclave it after every
case. Xcelerant provides an integrated handle that is totally
disposable. Each catheter comes with a handle, and the physician can just
dispose of the entire unit after each case."
The unit is designed with overmolded plastic assemblies that snap
together. There are no fasteners required for assembling the product,
reducing the number of operators on the line and making the line much
There are many overmolded
plastics parts used in the design, and extruded tubes with plastic parts
overmolded onto them. To achieve the ergonomic design and the scalability
requirements of the company's various product lines, simplifying assembly and
eliminating the need for fasteners was an important design goal. The
product is designed for multiple French sizes in order to accommodate the
requirements of individual product lines and maintain totally scalability in the
One design objective was to carefully design the subassemblies, so
Medtronic could reduce final assembly operations on the line and outsource
manufacturing responsibilities to Phillips Plastics for these molded
"That's one reason why we chose to overmold as many parts as possible," Doig
says. On previous projects, Medtronic would have an extruded tube, molded
a part, and glued it on. But overmolding provided a method for snapping
the entire assembly together by creating junctions between the mechanized handle
and the extrusions.
The design completely eliminates all
mechanical fasteners and minimizes gluing operations, and utilizes
overmolded plastic parts to create a strong industrial
The Xcelerant delivery system provides a
convenient, ergonomic method for doctors to utilize slow, controlled or
rapid deployment of stent grafts.
An exploded view of the Xcelerant
delivery system shows how the design snaps together and dramatically
reduces final assembly costs.