Reciprocating Stent Advancement for Precise Sheath-Free Deployment
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Solution Overview
Problem
Current stent delivery devices face challenges in efficiently deploying self-expanding stents within body vessels or ducts, particularly in maintaining stent expansion and axial density control during deployment, and in providing user-friendly operation for precise stent placement.
Innovation Solution
A stent deployment device featuring a stent-engaging element that operates in a reciprocating manner to advance the stent distally out of an outer sheath without mechanically withdrawing the sheath, coupled with a stent-retention element for maintaining contact during proximal movement and allowing re-sheathing, and methods for varying stent axial density by adjusting the sheath's axial position.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If a stent-engaging element mechanically withdraws the outer sheath to deploy the stent, then the stent deployment is achieved, but the device complexity and mechanical operation difficulty increase
Solution Approach 1:
Instead of mechanically withdrawing the outer sheath to deploy the stent, the invention inverts the approach by keeping the sheath stationary and using a reciprocating stent-engaging element to push the stent forward. This eliminates the need for complex mechanical withdrawal mechanisms while achieving the same deployment result.
Solution Approach 2:
The invention extracts the mechanical withdrawal function from the outer sheath and transfers it to a dedicated reciprocating stent-engaging element. This separation allows the sheath to remain simple and stationary while the engaging element handles the complex reciprocating motion for stent advancement.
2Productivity
If the stent-engaging element moves continuously to advance the stent, then deployment speed increases, but control precision and axial density control decrease
Solution Approach 1:
The stent-engaging element performs periodic reciprocating movements rather than continuous motion. Each cycle consists of a distal movement to advance the stent and a proximal movement to reset, allowing controlled incremental progression that maintains both deployment efficiency and precise axial density control.
Solution Approach 2:
The reciprocating element introduces dynamic control to the deployment process, allowing the operator to adjust the frequency, amplitude, and timing of each reciprocating cycle. This dynamic approach enables precise control over stent advancement rate and axial density while maintaining deployment speed.
3Adaptability or versatility
If the stent-retention element maintains continuous contact with the stent, then repositioning capability is improved, but the ease of final deployment is reduced
Solution Approach 1:
The stent-retention element operates periodically rather than continuously. It engages the stent during reciprocating movements to enable repositioning, then disengages to allow final deployment. This periodic engagement provides repositioning capability when needed while eliminating interference during the final deployment phase.
Solution Approach 2:
The retention element's contact status dynamically changes based on deployment stage. It transitions from an engaged state during repositioning operations to a disengaged state during final deployment, providing adaptability without compromising ease of operation at any given phase.
4Manufacturing precision
If multiple reciprocating movements are used to advance the stent, then axial density control is improved, but the time required for deployment increases
Solution Approach 1:
Multiple reciprocating movements are employed to achieve precise axial density control, with each cycle advancing the stent a controlled amount. The periodic nature allows for efficient incremental progression that maintains precision while minimizing total deployment time through optimized cycle frequency and amplitude.
Data Source
Figure 1
Figure 2A~2B
Figure 2C
AI summary
Devices and methods for stent advancement, including methods for instructing another or others how to advance a stent into an anatomical structure or into a testing/demonstration synthetic structure, such as a polymer tube. The advancement may be achieved by at least two periods of stent engagement that drive a stent distally from a sheath separated by a period of non-engagement.