Helical Screw Pump Thrombectomy Catheter
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Solution Overview
Problem
Current medical devices are inadequate for safely and effectively removing occlusive materials from narrow or tortuous vascular regions without causing further complications, such as embolism or stroke, due to limitations in aspiration and infusate flow rates and the risk of debris dispersal.
Innovation Solution
A flexible catheter system with a helical screw pump mechanism that navigates tortuous vascular paths, features a working head that can laterally displace from a guidewire to access occlusions, and includes a design with varying helix pitches and independent core and helix rotation to prevent clogging and ensure effective debris removal.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If rotary cutting heads or macerators are used to remove clots, then mechanical restoration of patency is improved, but loose debris may travel away to cause embolism or stroke
Solution Approach 1:
A distal protection device is introduced as an intermediary component between the clot and the bloodstream. This device captures and contains debris at the treatment site, preventing it from traveling distally to cause embolism while allowing the thrombectomy procedure to proceed effectively
Solution Approach 2:
The harmful factor (loose debris) is extracted and contained within the distal protection device. The device selectively removes the dangerous debris from the bloodstream while allowing normal blood flow to continue, thus eliminating the embolism risk without compromising clot removal efficacy
2Productivity
If high-speed rotation of fixed twin filament rotor is used for fluid transfer, then pumping efficiency is improved, but leakage through clearance between rotor and needle increases
Solution Approach 1:
The patent utilizes the viscosity of the liquid and high-speed rotation parameters to minimize leakage. By operating at high rotational speeds, the centrifugal forces and viscous effects reduce the relative importance of clearance gaps, thereby minimizing fluid leakage while maintaining efficient transfer
3Productivity
If sharp-edged rotating cutting tip is used to remove hard deposits, then plaque removal efficiency is improved, but damage to soft arterial tissue may occur
Solution Approach 1:
The cutting tip is designed with selective engagement characteristics where the sharp edges engage preferentially with hard plaque deposits due to their mechanical properties, while the soft arterial tissue is spared from damage. The local interaction characteristics differ based on the material being cut, achieving selective removal
4Productivity
If rotating burr is extended laterally away from guidewire to clear asymmetrical plaque, then plaque removal capability is improved, but risk of contact with normal vascular tissue increases
Solution Approach 1:
The rotating burr is designed with dynamic positioning capabilities, allowing it to be extended laterally away from the guidewire only when needed to clear asymmetrical plaque. The burr can be retracted or repositioned dynamically to avoid contact with normal vascular tissue, adapting its position based on the specific anatomical requirements
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 system enables safe and efficient removal of occlusive materials from narrow or tortuous vessels by maintaining adequate aspiration vacuum and infusate flow, minimizing the risk of debris dispersal and ensuring effective patency restoration with reduced blood loss and procedural time.
Implementation Method 1
A flexible catheter system with a helical screw pump mechanism that navigates tortuous vascular paths
Implementation Method 2
rotating, the fibrin may be drawn to a port by suction applied at the proximal end, thereby engaging the fibrin with the rotating, wrapping action of the helical coil wire
Data Source
Figure 1
Figure 2A
Figure 2B~2C
AI summary
A device suitable for removing material from a living being is provided, featuring at least an aspiration pump, powered by a motor. The aspiration pump and any optional infusate pump preferably feature a helical pumping mechanism, and operate at a high rate of rotation, thereby ensuring adequate pumping performance and flexibility. The helical pumping mechanism may be a helical coiled wire about a central core tube. The helical coil wire, whether together with, or independent of, the core tube, may be rotated to cause a pumping action. Additionally, a narrow crossing profile is maintained, ensuring that the device may reach more tortuous regions of the vasculature. In one embodiment, the system comprises a wire-guided mono-rail catheter with a working head mounted on a flexible portion of the catheter that can laterally displace away from the guide wire to facilitate thrombus removal. The working head may be operated to separate and move away from the guide wire to come within a closer proximity of the obstructive material to more effectively remove it from the vessel.