Pneumatic Sheath Retraction for Endoluminal Prosthesis Delivery
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Solution Overview
Problem
Existing endoluminal prosthesis deployment devices require significant manual force, typically around 22.5 pounds or 100 Newtons, to retract the sheath, which can be tiresome for operators and is undesirable due to the high resistance needed.
Innovation Solution
A pneumatic operating mechanism using a contractible air vessel, such as a tubular bellows, is coupled with the sheath and delivery catheter to facilitate the retraction of the sheath over the catheter, allowing for pneumatic contraction to reduce the force required for deployment, and includes features like a check valve and mechanical conversion mechanisms to enhance efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Shape
If the delivery catheter, sheath, and prosthesis are tightly interconnected to provide a low-diameter profile, then the radial profile is reduced allowing atraumatic access, but the force required to retract the sheath increases significantly
Solution Approach 1:
The patent replaces the purely mechanical manual retraction system with a hybrid pneumatic-mechanical system. A balloon catheter is used to inflate a balloon within the sheath, creating radial outward pressure that forces the sheath to retract from the delivery catheter. This substitutes manual mechanical pulling with pneumatic pressure-driven retraction, significantly reducing the operator force required while maintaining the tight interconnection of components for low-profile delivery.
2Ease of operation
If manual retraction force is increased to overcome tight interconnections, then sheath retraction is achieved, but operator fatigue increases
Solution Approach 1:
The patent introduces a pneumatic system using a balloon catheter that can be inflated with fluid or gas. When the balloon is inflated, it exerts radial outward pressure against the inner surface of the sheath, creating a pressure differential that forces the sheath to retract from the delivery catheter. This pneumatic mechanism eliminates the need for operators to apply high manual forces, thereby reducing operator fatigue while maintaining effective sheath retraction.
3Volume of moving object
If the sheath and delivery catheter are tightly interconnected, then a compact low-diameter profile is achieved, but the resistance to sheath movement increases
Solution Approach 1:
The patent introduces a balloon as an intermediary element between the delivery catheter and the sheath. This balloon serves as a mediator that, when inflated, generates radial pressure to push the sheath outward and force it to retract from the delivery catheter. The balloon intermediary converts the problem of high friction resistance into a controlled pressure-driven separation, allowing the tightly interconnected components to be separated with minimal operator force while maintaining the compact profile during delivery.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The pneumatic operating mechanism significantly reduces the force needed for sheath retraction, making the deployment process less strenuous for operators and potentially increasing control and precision during the procedure.
Implementation Method 1
pneumatic contraction of the air vessel causes the sheath to retract proximally over the delivery catheter
Data Source
AI summary
A system for delivering and deploying an expandable endoluminal prosthesis comprises a delivery catheter and a sheath. The delivery catheter has a proximal end and a distal end and is slidably disposed within a lumen of the sheath. An operating mechanism comprises a contractible air vessel that couples the sheath and the delivery catheter so that contraction of the air vessel causes the sheath to retract proximally over the delivery catheter. Additional aspects of the invention include a method of deploying an expandable endoluminal prosthesis.