Biostimulator Torque Limiter for Safe Leadless Pacemaker Retrieval
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Solution Overview
Problem
Existing biostimulator transport systems face challenges with excessive torque buildup during the delivery or retrieval of leadless pacemakers, which can lead to system damage and tissue injury due to high resistance from tissue ingrowth over time.
Innovation Solution
A biostimulator transport system incorporating a torque limiter mechanism that allows the torque shaft to slip relative to a handle when a resistance torque threshold is exceeded, featuring a slip mechanism such as a flat spring, clutch assembly, ball plunger, or shear pin to manage and release built-up torque, preventing excessive force transmission.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the biostimulator remains implanted for a long time, then tissue ingrowth occurs providing secure anchoring, but the torque required for removal increases to dangerous levels
Solution Approach 1:
The torque limiter acts as an intermediary component between the handle and the torque shaft. It allows torque to be transmitted during delivery and implantation, but intervenes to limit excessive torque during removal when tissue ingrowth creates high resistance, preventing damage to the biostimulator or surrounding tissue.
Solution Approach 2:
The torque limiter changes the torque parameter transmitted through the system based on the resistance encountered. When resistance torque exceeds a predetermined threshold (indicating tissue ingrowth), the torque limiter reduces the output torque to a safe level, effectively changing the torque parameter from high to low to prevent damage.
2Ease of operation
If high torque is applied to unscrew the biostimulator from target tissue, then removal is achieved, but the biostimulator transport system may be damaged
Solution Approach 1:
The torque limiter provides beforehand cushioning by being pre-installed in the torque shaft assembly. It is designed to engage and limit torque before excessive force can damage the biostimulator or surrounding tissue, cushioning against the harmful effects of high removal torque.
Solution Approach 2:
The torque limiter converts the harmful high torque generated by tissue ingrowth into a beneficial limited torque. By allowing the slip mechanism to engage, it transforms the potentially damaging force into a controlled, safe level of torque that maintains system integrity while still enabling removal.
3Reliability
If high torque is applied during biostimulator removal, then anchoring is overcome, but tissue injury may occur
Solution Approach 1:
The torque limiter converts the harmful high torque that would cause tissue injury into a beneficial limited torque. By allowing the slip mechanism to engage when resistance exceeds the threshold, it transforms the potentially damaging force into a controlled, safe level of torque that protects surrounding tissue while still enabling removal.
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 torque limiter effectively reduces the risk of system damage and tissue injury by limiting torque output, ensuring safe and efficient delivery or retrieval of biostimulators while maintaining system integrity.
Implementation Method 1
a slip mechanism between the torque puck and the torque shuttle, and can connect the components rotationally. The torque shuttle can be coupled to a handle and can transmit torque to the torque puck through the slip mechanism when a resistance torque at the docking cap is below a torque threshold.
Data Source
AI summary
A biostimulator transport system, such as a biostimulator retrieval system, having a torque limiter to allow a torque shaft to slip rotationally relative to a handle, is described. The torque limiter can connect the torque shaft to the handle, and can include a slip mechanism, such as a flat spring or apposed clutch faces, that allow the torque shaft to slip relative to the handle when a resistance torque at a distal end of the torque shaft exceeds a torque threshold. Accordingly, torque can be applied to a biostimulator by the torque shaft with a reduced likelihood of over-torqueing the biostimulator within the target tissue. Other embodiments are also described and claimed.