Torque Limiting Handle for Crossing Vascular Occlusions
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Solution Overview
Problem
Current endovascular devices and techniques for treating chronic total occlusions are inefficient, pose a high risk of vessel perforation, and often fail to cross the occlusion, making it difficult for physicians to visualize and direct devices accurately through the vascular lumen.
Innovation Solution
A device comprising a shaft with a handle assembly that includes a torque limiting mechanism, allowing rotation of the shaft when torque applied is below a maximum torque threshold, and preventing further rotation when the torque exceeds this threshold, facilitating safe and effective navigation through vascular occlusions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional endovascular devices are used to cross chronic total occlusions, then the procedure may be time-consuming and risky, but the devices often fail to cross the occlusion or perforate the vessel
Solution Approach 1:
The device changes the torque parameter dynamically during operation. The torque limiting mechanism allows rotation up to a predetermined maximum torque threshold, then prevents further rotation. This parameter control enables the device to cross occlusions efficiently while preventing vessel perforation by limiting excessive torque application.
Solution Approach 2:
The torque limiting mechanism provides real-time feedback to the operator through tactile or visual indicators when the maximum torque threshold is reached. This feedback system allows the operator to understand when the shaft is encountering resistance and when torque limits are approaching, enabling safer and more efficient crossing of occlusions.
2Productivity
If the shaft is made rotatable to facilitate navigation through occlusions, then crossing efficiency improves, but the risk of vessel perforation increases due to loss of control
Solution Approach 1:
The device implements dynamic torque control where the rotation capability is not fixed but adapts based on the operational conditions. The torque limiting mechanism dynamically adjusts the rotation allowance, permitting rotation when torque is below the threshold and preventing rotation when the threshold is reached. This dynamic control enables efficient navigation while preventing perforation.
Solution Approach 2:
The torque limiting mechanism acts as a preventive measure that is built into the device before damage can occur. By pre-establishing a maximum torque threshold and enforcing it through the limiting mechanism, the device cushions against the harmful effect of vessel perforation before it can happen, while still allowing necessary rotation for crossing occlusions.
3Reliability
If torque limiting mechanism is added to control rotation, then safety improves, but device complexity increases
Solution Approach 1:
The torque limiting mechanism uses an intermediary element (such as a spring-loaded arm, cam, or ratchet system) between the handle assembly and the shaft. This intermediary component mediates the torque transmission, allowing rotation up to a limit and then preventing further rotation. The intermediary mechanism provides precise control while adding minimal complexity to the overall device.
4Ease of operation
If the handle assembly allows free rotation, then ease of operation improves, but the ability to prevent excessive torque is lost
Solution Approach 1:
The handle assembly transitions from free rotation to controlled rotation based on the torque conditions. Below the maximum torque threshold, the handle assembly allows free rotation for ease of operation. When the threshold is reached, the torque limiting mechanism engages to prevent excessive torque. This dynamic behavior maintains ease of operation during normal use while ensuring safety during critical moments.
Data Source
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AI summary
The present invention discloses a device for facilitating treatment of a blood vessel, the device comprising: a shaft having a distal end and a proximal end; a handle assembly disposed about the shaft; and the handle assembly comprising a first portion and a torque limiting mechanism coupling the first portion to the shaft; wherein the torque limiting mechanism allows relative movement between the first portion and the shaft when the first portion is being rotated in a first direction and a torque applied to the shaft has exceeded a first maximum torque; wherein the torque limiting mechanism transfers torque between the first portion and the shaft when the first portion is being rotated in the first direction and the torque applied to the shaft is less than or equal to the first maximum torque.