Cincher Tube Retrieval for Leadless Pacemaker Abrasion Control
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Solution Overview
Problem
Existing retrieval systems for leadless cardiac pacemakers face issues with torque shaft abrasion due to metal-to-metal contact during the cinching and retrieval process, increasing the risk of device failure.
Innovation Solution
A biostimulator retrieval system with a torque shaft attached to a docking cap and a cincher tube that is independently movable relative to the torque shaft, isolating the snare from direct contact to prevent abrasion, using a cincher tube with a solid inner surface to facilitate smooth actuation and torque transmission.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If the torque shaft is used to both cinch the snare and transmit torque, then the device complexity is reduced, but the torque shaft undergoes abrasion increasing the risk of device failure
Solution Approach 1:
The patent divides the torque shaft into two separate components: a cincher tube for cinching the snare and a separate torque transmission shaft for transmitting torque. This segmentation eliminates the wear and abrasion that occurs when a single shaft performs both functions, thereby improving device reliability while maintaining acceptable complexity levels.
Solution Approach 2:
The patent introduces a bearing as an intermediary component between the cincher tube and the torque transmission shaft. This bearing allows the cincher tube to move independently without contacting the torque shaft, eliminating direct metal-to-metal contact and abrasion, thus protecting the torque shaft from wear while enabling independent cinching motion.
2Strength
If the torque shaft is a metallic cable structure, then torsional stiffness for torque transmission is achieved, but the metallic strands abrade when the torque shaft is advanced to cinch the snare
Solution Approach 1:
The bearing acts as an intermediary that prevents the cincher tube from sliding over the torque transmission shaft. This eliminates the harmful abrasion of the metallic strands while allowing the torque shaft to maintain its torsional stiffness for effective torque transmission during retrieval.
Solution Approach 2:
By separating the cinching function (performed by the cincher tube) from the torque transmission function (performed by the metallic torque shaft), the patent eliminates the abrasion problem that occurs when the metallic cable structure is used for both purposes. The segmented design allows each component to be optimized for its specific function without compromising the other.
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
Prevents abrasion of the torque shaft by isolating the snare from direct contact, ensuring reliable and efficient retrieval of leadless cardiac pacemakers without compromising the integrity of the device.
Implementation Method 1
The docking cap is rotatably coupled to the outer catheter by a bearing
Data Source
AI summary
A retrieval system for a biostimulator, such as a leadless cardiac pacemaker, is described. The biostimulator retrieval system includes a docking cap rotatably coupled to an outer catheter by a bearing. A torque shaft extends through the outer catheter and attaches to the docking cap to transmit torque to the docking cap to cause rotation of the docking cap relative to the outer catheter. The rotating docking cap can transmit torque to an attachment feature of a biostimulator received within the docking cap. The attachment feature can be captured by a snare that extends through the torque shaft. A cincher tube extends through the torque shaft around the snare, and advances over the snare independently from the torque shaft that is attached to the docking cap, to cinch the snare onto the attachment feature. Other embodiments are also described and claimed.