Medical Device with Flexible Mesh Support for Atherectomy
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Solution Overview
Problem
Existing medical devices for cutting substances from the inner wall surface of body lumens, such as those with expandable and contractible bars, risk damaging normal blood vessels and can be damaged by hardened stenosis substances like calcified plaque.
Innovation Solution
A medical device with a rotatable drive shaft, an expandable strut with a bent central portion, and a support portion that is mesh-shaped and tubular, allowing for radial expansion and reducing the risk of device damage and tissue injury.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If expandable and contractible bars are used to enable easy delivery into body lumens, then the device can be easily delivered, but the edge of the bars comes into contact with the blood vessel causing considerable risk of damage to normal blood vessels
Solution Approach 1:
The patent replaces rigid expandable bars with a flexible mesh structure that can expand radially. The mesh structure comprises interconnected struts that form a flexible yet supportive framework, allowing the device to expand gently against the blood vessel wall without concentrated edge contact points that would cause damage.
Solution Approach 2:
The mesh structure inherently creates a porous configuration with gaps between struts. This porous design allows the device to maintain structural integrity while reducing contact pressure on the blood vessel wall, preventing damage while still providing radial expansion capability for easy delivery.
2Productivity
If a hardened stenosis substance such as calcified plaque is cut, then the stenosis substance is caught in a gap between the bars, thereby causing an increasing possibility that the device may be damaged
Solution Approach 1:
The mesh structure with controlled gaps allows cut pieces of hardened plaque to pass through rather than become trapped. The gap size is designed to accommodate typical atherectomy debris while maintaining structural support, preventing device damage from trapped substances.
Solution Approach 2:
The mesh structure provides dynamic flexibility during the cutting process, allowing the struts to move and adjust as plaque is cut. This dynamic response prevents rigid stress concentration that could lead to device damage while maintaining effective cutting capability.
3Area of stationary object
If the strut is expanded radially outward to ensure proper cutting range, then the cutting range is ensured, but the edge of the strut may come into contact with biological tissues causing excessive damage
Solution Approach 1:
The flexible mesh structure allows radial expansion to provide adequate cutting range while distributing contact pressure across the entire mesh surface rather than concentrating it at discrete bar edges. This flexibility enables the structure to conform to the vessel wall geometry, reducing focal points of tissue damage.
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 device can be easily delivered into body lumens, ensures a proper cutting range, reduces tissue damage, and prevents device damage by avoiding substance entrapment between the strut and support portion.
Implementation Method 1
at least one strut that is rotatably connected to a distal side of the drive shaft, that extends along a rotation axis, and whose central portion is bent so as to be expandable radially outward
Implementation Method 2
a support portion that is rotatably connected to the distal side of the drive shaft that is formed in a mesh shape and a tubular shape while including multiple gaps, at least a portion of which is positioned on a radially inner side of the strut, and that is expandable radially outward by a central portion in a direction extending along the rotation axis being bent
Data Source
AI summary
A treatment method and medical device are disclosed for cutting a substance inside a body lumen. The medical device includes a drive shaft that is rotatable; a cutting unit configured to be rotatably connected to a distal side of the drive shaft; a filter device configured to be inserted in a contracted state, the filter device having an elongated shaft, which interlocks with a filter portion of the filter device; a distal tube, the distal tube being on a distal side of the cutting unit and configured to receive the elongated shaft of the filter device; and a housing on a proximal portion of the drive shaft, the housing including a first drive gear connected to the drive shaft, a second drive gear connected to a motor and meshing with the first drive gear, and a first partition wall arranged between the motor and the second drive gear.