Intravascular Tissue Removal Tool with Internal Cutting Forceps

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Solution Overview

Problem

Fibrin strands that form in venous vessels after blood clots dissolve can obstruct and thicken vessel walls, limiting elasticity, and existing methods for removal are complex and risk injury to the vessel walls.

Innovation Solution

An intravascular tissue removal tool with a flexible sheath, cutting elements, and a forceps mechanism that can be actuated to grab and sever tissue while minimizing risk to the vessel walls, using a tubular ring with cutting elements inside the sheath to prevent external injury.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If complex tools are used to remove fibrin strands, then tissue removal capability is improved, but device complexity increases

Engineering Contradiction:

Improvetissue removal capabilityVSAvoiddevice complexity

Core Design Contradiction:

ProductivityVSDevice complexity

Solution Approach 1:

The device is divided into distinct functional modules: a flexible sheath for navigation, a forceps mechanism for tissue grasping, and cutting elements for severing fibrin. This segmentation allows each component to perform its specific function efficiently while keeping the overall device manageable in complexity.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The forceps mechanism and cutting elements are nested within the flexible sheath, allowing the device to maintain a compact profile during insertion while providing full functionality during operation. The cutting elements are positioned inside the sheath lumen, and the forceps can be extended or retracted as needed.

Inventive Principle:

Principle #7Nested doll (Nesting)

2Productivity

If cutting elements are placed outside the sheath for easier access, then tissue cutting efficiency is improved, but risk of injury to vessel wall increases

Engineering Contradiction:

Improvetissue cutting efficiencyVSAvoidrisk of injury to vessel wall

Core Design Contradiction:

ProductivityVSObject-affected harmful factors

Solution Approach 1:

The flexible sheath acts as an intermediary protective barrier between the cutting elements and the vessel wall. The cutting elements are positioned inside the sheath lumen, allowing them to cut tissue that is pulled into the sheath while the sheath itself protects the surrounding vessel wall from direct contact with the sharp cutting elements.

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

Instead of having cutting elements exposed outward for direct cutting, the design inverts the approach by placing cutting elements inside the sheath and pulling tissue inward to be cut. This reversal of the traditional cutting element positioning eliminates the risk of external contact with the vessel wall while maintaining cutting effectiveness.

Inventive Principle:

Principle #13The other way round (Inversion)

3Object-affected harmful factors

If forceps are kept retracted inside the sheath, then vessel wall protection is improved, but tissue grasping capability is reduced

Engineering Contradiction:

Improvevessel wall protectionVSAvoidtissue grasping capability

Core Design Contradiction:

Object-affected harmful factorsVSEase of operation

Solution Approach 1:

The forceps mechanism is designed to be dynamic, allowing it to extend from the sheath when tissue grasping is needed and retract when not in use. The actuation member enables the forceps to move between extended and retracted positions, providing full tissue access capability when required while maintaining vessel wall protection during navigation and non-operational phases.

Inventive Principle:

Principle #15Dynamics

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

Effectively removes fibrin strands and other tissue from body vessels while reducing the risk of injury to the vessel walls, allowing safe reopening of obstructed vessels.

Implementation Method 1

cutting elements extending into the lumen near the distal end of the flexible sheath

Methodology Applied

Scientific EffectMechanical cutting: Fracture Mechanics

Implementation Method 2

Vacuum applied to the flexible sheath from the proximal end may aid the removal of tissue

Methodology Applied

Scientific EffectVacuum suction: Suction

Data Source

PatentUS9198681B2Device and method for removing tissue inside a body vessel

Publication Date: 2015.12.01 COOK MEDICAL TECHNOLOGIES LLC

AI summary

An intravascular tissue removal tool has an elongated flexible sheath with a proximal end, a distal end, and a lumen extending from the proximal end to the distal end, the lumen having a distal lumen diameter near the distal end; cutting elements extending into the lumen near the distal end of the flexible sheath; a forceps having an open state and a closed state, and further having an extended position relative to the flexible sheath, in which the forceps is located substantially outside the flexible sheath near the distal end and a retracted position relative to the flexible sheath, in which the forceps is located substantially inside the flexible sheath; and an elongated actuation member being attached to the forceps for switching the forceps between the open state and the closed state and for moving the forceps between the extended state and the retracted state.