Spring-Biased Catheter Capture Members for Misaligned Device Retrieval
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Current catheters face difficulties in efficiently retrieving implantable medical devices from implant sites due to misalignment issues between the device receptacle's opening and the device's housing, leading to challenges in capturing and removing the device without causing damage or requiring excessive force.
Innovation Solution
The catheter features an engagement subassembly with spring-biased capture members and segments that expand to accommodate the device, allowing for secure engagement and retrieval by aligning with the device's attachment feature, even in misaligned positions, and includes a pull band and pull wire for deflection and disengagement.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a traditional catheter with a fixed device receptacle is used, then the structure is simple, but misalignment between the receptacle opening and device housing prevents successful retrieval
Solution Approach 1:
The catheter employs spring-biased capture members that can dynamically change their configuration between a compressed state (when contained within the receptacle) and an expanded state (when engaging the device). This dynamic capability allows the capture members to adapt to misalignment conditions by expanding outward to engage the device housing even when the receptacle opening is not perfectly aligned with the device, thereby improving retrieval success without requiring a completely complex catheter structure.
Solution Approach 2:
The engagement subassembly is divided into multiple independent capture members (at least three segments) that can move and expand independently. Each capture member includes a grip portion that can independently engage the device housing. This segmentation allows the system to accommodate misalignment by having individual segments adjust their positions, while the overall structure remains relatively simple and manageable.
2Productivity
If excessive force is applied to retrieve a misaligned device, then the device can be removed, but the device housing may be damaged
Solution Approach 1:
The capture members utilize spring bias to provide a controlled, progressive engagement force. Instead of applying sudden excessive force, the spring mechanism allows for gradual force application as the capture members expand and engage the device housing. This parameter change in force application (from sudden to progressive) enables efficient retrieval while preventing damage to the device housing.
Solution Approach 2:
The spring-biased design inherently provides cushioning by absorbing and distributing the forces involved in engagement and retrieval. The elastic nature of the spring mechanism prevents sudden force spikes that could damage the device, while still providing sufficient force to overcome misalignment and successfully retrieve the device.
3Ease of operation
If spring-biased capture members are used to overcome misalignment, then engagement is improved, but the device complexity increases
Solution Approach 1:
The spring-biased capture members are designed to automatically expand and engage the device housing when the engagement subassembly is positioned near the device. The spring mechanism provides self-actuating engagement without requiring complex external actuation systems, making the operation simple while the internal spring mechanism handles the complexity of adaptive engagement.
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
This design enhances the ease and efficiency of retrieving medical devices by overcoming misalignment issues, allowing for secure capture and removal without damaging the device or requiring excessive force, thereby improving the overall retrieval process.
Implementation Method 1
at least three capture members arranged around a longitudinal axis of the engagement subassembly and being spring biased outward from the longitudinal axis
Implementation Method 2
the device receptacle of the catheter outer assembly forces the capture members/segments, against the spring bias thereof, toward the longitudinal axis
Data Source
AI summary
An engagement subassembly of a catheter, for retrieving an implanted medical device, may include at least three segments or, alternately, capture members being spring biased outward from a longitudinal axis of the subassembly, wherein a device receptacle of the catheter forces the capture members/segments, against the spring bias thereof, toward the axis. Each capture member includes a spring-biased wire and a grip, which is located between proximal and distal portions of the corresponding wire, and which is configured to interlock within a gap between a device attachment feature and housing; a length of each wire distal portion may be approximately equal to that of the device housing. An interlocking edge of each segment interlocks within the gap between the attachment feature and housing, when a distal-facing surface of each segment, which tapers outward from the axis in a distal direction, comes into confronting engagement with the device housing.