Interventional Medical Device Tethering and Mandrel Interlock
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Solution Overview
Problem
Traditional implantable cardiac pacemakers with elongate lead wires face mechanical and MRI compatibility issues, prompting the need for compact devices that can be implanted close to the pacing site, requiring improved methods for securing the device to a catheter during implantation.
Innovation Solution
A compact implantable medical device system featuring a tethering member and holding member that interlock, with a tethering member comprising an elongate shaft and connector portion, and an elongate mandrel for sliding engagement, allowing for easy loading and secure attachment to a catheter, and optional elastically deformable jaw elements for enhanced interlocking.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a tethering member is looped through a holding member and threaded through catheter lumens to secure the device to the catheter, then the device can be securely attached and repositioned during implantation, but the process becomes tedious and complex
Solution Approach 1:
A mandrel is introduced as an intermediary tool that simplifies the attachment process. The mandrel engages with the tethering member and holding member assembly, providing a mechanical interface that automatically secures the device to the catheter when the mandrel is advanced. This intermediary mechanism eliminates the need for manual looping and threading operations, reducing procedural complexity while maintaining secure attachment.
Solution Approach 2:
The tethering member is pre-configured with a loop structure and the holding member is pre-positioned on the device housing before implantation. This preliminary preparation allows the components to be quickly engaged with each other and the mandrel during the procedure, eliminating the need for complex real-time manipulation and reducing the tedious nature of the attachment process.
2Duration of action of stationary object
If the device is packaged separately from the catheter to extend shelf life, then storage and sterility are improved, but the ease of loading the device into the catheter during implantation is reduced
Solution Approach 1:
The mandrel serves as a mediating tool that bridges the separately packaged device and catheter during the loading process. By engaging the mandrel with the pre-configured tethering member and holding member assembly, the operator can easily load the device into the catheter through a simple advancement motion, overcoming the difficulty introduced by separate packaging while preserving shelf life benefits.
Solution Approach 2:
The system is divided into separable components (device with holding member, catheter with tethering member) that can be independently packaged for extended shelf life. The segmentation allows each component to be sterilized and stored separately, then quickly reassembled during implantation using the mandrel as a coupling mechanism, thus maintaining both shelf life extension and loading ease.
3Object-affected harmful factors
If a compact device is implanted close to the pacing site to avoid lead wire issues, then mechanical and MRI compatibility problems are resolved, but the need for secure and easy repositioning during implantation becomes more critical
Solution Approach 1:
The mandrel acts as a temporary intermediary that maintains control over the compact device during implantation and repositioning operations. Because the device is securely attached to the catheter via the mandrel-tethering member-holding member mechanism, the operator can easily manipulate and reposition the device within the catheter or withdraw it for reimplantation at a different site, addressing the critical need for repositioning capability despite the device's compact design.
Solution Approach 2:
The attachment system provides dynamic control during implantation. The mandrel can be advanced to secure the device in place or withdrawn to release it, allowing the device to transition between fixed and mobile states. This dynamic capability enables easy repositioning of the compact device during the procedure while maintaining secure attachment when needed.
Data Source
AI summary
In an interventional medical system, a tethering member of a catheter assembly and a holding member of a relatively compact implantable medical device are configured to interlock with one another. The tethering member includes an elongate shaft portion and a connector portion coupled to a distal end of the shaft portion, wherein the connector portion is configured to pass through a proximal-facing opening of a cavity defined by the device holding member, and to interlock with the holding member within the cavity. The connector portion of the tethering member includes a lumen extending longitudinally therethrough, which has a distal opening in fluid communication with the cavity of the device holding member, when the connector portion interlocks therewith. The catheter assembly further includes an elongate mandrel, which has a distal tip configured to extend within the lumen of the tethering member connector portion, being in sliding engagement therewith.