Stent Delivery System Proximal Sheath Retraction
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Solution Overview
Problem
Existing stent deployment systems are prone to unintended stent expansion at sites distal to the intended location due to awkward handle mechanisms, leading to inaccurate placement and potential complications during sheath retraction.
Innovation Solution
A stent deployment system with a handle mechanism where the sheath retraction is controlled by a proximal movement, utilizing an inner and outer tubular member configuration with an intermediate tubular member and a coupling mechanism that allows for precise longitudinal movement to expose the stent, reducing the risk of inner tubular member movement during deployment.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If the sheath manipulator is located toward the distal end of the fixed handle, then the sheath can be retracted, but the handle mechanism becomes awkward and may cause unintended stent expansion at distal sites
Solution Approach 1:
The patent inverts the conventional handle mechanism design by moving the sheath manipulator from the distal end to the proximal end of the handle. This inversion allows the physician to control sheath retraction from a more ergonomic position, eliminating the need to push the handle distally during manipulation, thereby preventing unintended stent expansion at distal sites.
Solution Approach 2:
The patent introduces a sliding handle as an intermediary component between the fixed handle and the sheath manipulator. This sliding handle acts as a mediator that allows controlled sheath retraction while maintaining stable positioning of the inner catheter, thus preventing unintended stent deployment.
2Device complexity
If the inner catheter is allowed to move axially during sheath retraction, then the handle mechanism is simpler, but the stent may expand at an untended site
Solution Approach 1:
The patent implements preliminary action by pre-positioning the coupling member to connect the inner catheter to the handle assembly before sheath retraction begins. This pre-established connection prevents axial movement of the inner catheter during the deployment process, ensuring the stent expands only at the intended site.
Solution Approach 2:
The coupling member serves as an intermediary element that bridges the inner catheter and the handle assembly. It provides a stable mechanical connection that prevents unintended axial movement of the inner catheter while allowing controlled sheath retraction, thus maintaining precise stent placement.
3Ease of operation
If the sheath manipulator is positioned distally on the handle, then sheath retraction is possible, but the physician must push the handle distally which causes the stent to expand at a distal location
Solution Approach 1:
The patent inverts the manipulation direction by positioning the sheath manipulator at the proximal end of the handle, allowing the physician to pull the handle proximally instead of pushing it distally. This inversion eliminates the harmful effect of unintended distal stent expansion while maintaining ease of sheath retraction control.
Solution Approach 2:
The sliding handle acts as an intermediary that decouples the sheath retraction action from the inner catheter position. It allows the physician to control sheath retraction through proximal pulling motion without transmitting this motion to the inner catheter, thereby preventing unintended stent expansion at distal sites.
Data Source
AI summary
A tubular prosthesis delivery system has an inner tubular member having a distal end including a prosthesis-carrying portion and a proximal end intended to remain outside the patient. An outer tubular member has a distal end spaced from the prosthesis-carrying portion of the inner member. A coupling member couples the inner and outer tubular members to each other in fixed relationship generally at a location intended to remain outside the patient. An intermediate tubular member located between the inner and outer tubular members has a distal end adapted to cover the tubular prosthesis and a proximal end that projects proximally beyond the proximal ends of both the inner and outer tubular members. The proximally projecting end of the intermediate tubular member is longitudinally movable with respect to the coupled inner and outer tubular members by a distance sufficient to retract the intermediate tubular member distal end from any position covering the prosthesis carried by the inner member.