Flexible Push-Rod Marker Delivery for Compact Side Ejection
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Solution Overview
Problem
Existing marker delivery devices for biopsy sites are cumbersome due to their length, making insertion difficult, and the ramp mechanism for deploying markers can compress and expand the marker, complicating its deployment through lateral apertures.
Innovation Solution
A marker delivery device with a push rod mechanism that includes a flexible cannula and a ramp to transition marker movement from longitudinal to transverse direction, minimizing device length and facilitating marker deployment through a side opening, using a push rod with a flexible beaded design and coordinated linear and rotational motion for marker deployment.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Length of moving object
If a long flexible cannula is used to reach the side aperture of the needle, then the marker can be delivered to the target location, but the device becomes cumbersome and difficult to insert into the needle
Solution Approach 1:
The device is divided into separate functional components: a shorter cannula for insertion, a push rod for marker advancement, and a ramp mechanism for lateral ejection. This segmentation allows each component to be optimized independently, with the cannula being short enough for easy insertion while still reaching the side aperture when combined with the extendable push rod.
Solution Approach 2:
The push rod is designed to be extendable along the longitudinal axis, transforming from a compact storage state to an extended delivery state. This dynamic extension allows the effective length of the delivery system to increase only when needed, maintaining ease of insertion while achieving the required reach to the side aperture.
2Ease of operation
If a ramp mechanism is used to change marker movement from longitudinal to transverse direction, then the marker can be deployed through the lateral aperture, but the marker is compressed and expanded making deployment difficult
Solution Approach 1:
The ramp mechanism is pre-configured at a specific angle and position within the cannula. As the push rod advances the marker longitudinally, the marker automatically engages the ramp and is redirected transversely through the lateral aperture. This preliminary configuration eliminates the need for complex real-time adjustments or manual compression/expansion operations during deployment.
Solution Approach 2:
The ramp acts as an intermediary element between the longitudinal push rod and the lateral ejection path. It converts the longitudinal force from the push rod into transverse motion, smoothly guiding the marker through the aperture without requiring direct manual manipulation or complex mechanical linkages that would increase device complexity.
3Volume of moving object
If the marker is compressed to fit through the lateral aperture, then the marker can be deployed, but the diameter of the marker expands making it difficult to deploy
Solution Approach 1:
Instead of compressing the marker in one dimension (longitudinally) to reduce its size, the ramp mechanism redirects the marker's motion into another dimension (transverse direction). This allows the marker to maintain its original diameter while still passing through the lateral aperture by changing the direction of ejection rather than reducing the marker's cross-sectional dimensions.
Data Source
AI summary
A marker delivery device includes a housing, a flexible push rod, and a wheel. The push rod includes a first transverse dive surface and a deployer tip. The deployer tip is configured to receive a biopsy site marker. The wheel includes a second transverse drive surface. The first transverse drive surface is configured to be driven by the second transverse drive surface to translate the push rod distally.