Interventional Catheter Actuator for Stent Length Control
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Solution Overview
Problem
Current stents and angioplasty catheters face challenges in treating long, curved, and tapered vascular regions due to stiffness and inability to conform to vessel curves, leading to restenosis, and there is a need for improved control and indication of balloon and stent length during minimally invasive procedures.
Innovation Solution
A catheter system with an elongated shaft comprising an inner and outer shaft, an interventional element with adjustable length, and an actuator that uses rotatable members and lead screws to precisely control the length of the interventional element, allowing for selective deployment and repositioning of stent segments or balloon lengths within the vessel.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional stents are used to provide intravascular support, then vascular patency is maintained, but restenosis occurs due to excessive stiffness and inability to conform to vascular curves
Solution Approach 1:
The stent is divided into multiple segments that can move relative to each other, allowing the stent to conform to curved and tapered vascular regions while maintaining structural support. The segments are connected by joints that enable bending and angular adjustment, resolving the contradiction between stiffness for patency and flexibility for conformability.
Solution Approach 2:
The stent transitions from a static rigid structure to a dynamic articulated structure that can adapt its shape in response to vascular geometry. The mechanical joints and degree of freedom mechanisms allow the stent to dynamically adjust its configuration to match the vessel's curvature and taper, eliminating restenosis caused by poor conformability.
2Ease of manufacture
If fixed-length stents are deployed, then deployment is simple, but treatment of multiple vascular sites requires multiple procedures
Solution Approach 1:
The stent delivery system incorporates multiple stent segments that can be independently deployed at different vascular sites. The segmented design allows the operator to deploy one segment, reposition the delivery catheter, and deploy additional segments, enabling treatment of multiple lesions in a single procedure while maintaining relatively simple deployment mechanics.
Solution Approach 2:
The delivery catheter is designed with universal capabilities to deploy stent segments at multiple locations along the vasculature. The same delivery system can treat different vascular sites with different stent configurations, providing multi-functionality that eliminates the need for separate procedures for each lesion.
3Reliability
If long balloons are used to treat extended lesions, then coverage is improved, but control and indication of balloon length becomes difficult
Solution Approach 1:
The balloon is divided into multiple inflatable segments along its length, allowing selective inflation of individual segments or combinations of segments. This segmented approach provides precise control over the effective treatment length, enabling the operator to treat extended lesions with accurate length control by inflating only the necessary segments.
Solution Approach 2:
The balloon transitions from a static single-length structure to a dynamic segmented structure where individual segments can be independently inflated or deflated. This dynamic control allows the balloon to adapt its effective length to match the specific lesion dimensions, improving both coverage and length control.
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 system provides accurate and precise control over the deployment and adjustment of interventional elements, such as stents and balloons, enabling effective treatment of complex vascular lesions while minimizing restenosis and improving procedural efficiency.
Implementation Method 1
a first threaded member configured to operatively couple a first lead screw to said outer shaft, said first threaded member configured to travel axially along said first lead screw as the first lead screw rotates
Implementation Method 2
a second threaded member configured to operatively couple a second lead screw to said inner shaft, said second threaded member configured to travel axially along said second lead screw as the second lead screw rotates
Data Source
Figure 1
Figure 2~2A
Figure 3~3A
AI summary
Devices and methods are provided for operating and controlling an interventional element on an interventional catheter. The interventional element may be a stent or series of stents, a balloon, or any other interventional element for which length control is necessary or desirable. A handle member includes an elongated body and an actuator knob that rotates around the longitudinal axis of the body. Rotational movement of the actuator knob is translated to rotational movement of one or more lead screws by a system of gears, rollers, or combinations of gears and rollers. Each of one or more axially moveable members is positioned on a lead screw and attached to a portion of the catheter shaft in order to provide the ability to advance or retract the portion of the cathether shaft.