Capture Device Force Reduction Element
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Solution Overview
Problem
Repetitive use of capture devices in noninvasive procedures, such as urology, leads to sheath damage due to radially-directed and proximally-directed forces, reducing device lifespan and increasing costs, potentially requiring invasive procedures if the sheath tears or buckles.
Innovation Solution
A medical device with a handle, actuator, plunger, and force reduction element that dissipates proximally-directed forces, preventing sheath damage by using a resilient element and a force reduction element with a low coefficient of friction, allowing for extended device durability and safe operation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the basket is expanded by the stone during capture, then the capture function is achieved, but the sheath is subjected to considerable radially-directed and proximally-directed forces that cause damage over time
Solution Approach 1:
A force reduction element is introduced as an intermediary component between the basket and the sheath. This element actively reduces the magnitude of forces transmitted to the sheath during basket expansion and retraction, thereby protecting the sheath from damage while maintaining the capture function
Solution Approach 2:
The force reduction element is pre-installed in the device structure to provide cushioning protection before any damage occurs. It is designed to absorb and reduce forces during normal operation, preventing cumulative damage that would otherwise lead to sheath failure
2Productivity
If the basket is retracted repeatedly into the sheath during the procedure, then multiple stones can be removed, but the sheath is subjected to repeated mechanical stress that reduces its useful life
Solution Approach 1:
The force reduction element serves as a protective intermediary that allows repeated retraction operations without transmitting damaging forces to the sheath. This enables multiple capture cycles while preserving sheath integrity and extending its useful life
Solution Approach 2:
The force reduction element provides pre-established protection against the cumulative mechanical stress of repeated retractions, allowing the device to maintain productivity over an extended period without sheath failure
3Reliability
If the sheath tears or buckles during the procedure, then the capture device cannot be safely removed, but replacing or repairing the device increases costs and may require invasive procedures
Solution Approach 1:
The force reduction element provides preventive protection that eliminates the risk of sheath failure during the procedure. By cushioning forces before they can cause damage, it ensures safe device removal and avoids the need for costly corrective interventions
Solution Approach 2:
The force reduction element converts potentially harmful forces into reduced, safe levels of stress. This transforms a situation that would normally lead to sheath damage into one that protects the sheath, turning a harmful factor into a beneficial protective mechanism
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 enhances the durability of the sheath by reducing the forces applied during the capture and retraction of objects, minimizing the risk of sheath damage and associated costs, while ensuring safe removal of stones or fragments without the need for invasive procedures.
Implementation Method 1
a resilient element located in the reaction chamber, the resilient element including a proximal end movable relative to plunger; and a force reduction element located in the reaction chamber between the proximal end of the resilient element and a proximal surface of the reaction chamber. The resilient element biases the plunger distally relative to the actuator. The resilient element is compressible when a proximally-directed force is applied to the plunger.
Implementation Method 2
The force reduction element dissipates an amount of the proximally-directed force. The force reduction element is movable relative to the actuator and the resilient element.
Data Source
Figure 1
Figure 2
Figure 3A~3B
AI summary
Numerous devices are described. One device may comprise: a handle (20) including a wire attachment portion; an actuator (30) movably mounted to the handle (20), the actuator (30) including a reaction chamber (39); a plunger (40) movably mounted to the actuator (30), the plunger (40) including a distal stop (44D) with a sheath attachment (46) portion, and a proximal stop (44P) located in the reaction chamber (39); a resilient element (80) including a distal end (80D) attached to the proximal stop (44P), and a proximal end movable relative to plunger (40); and a force reduction element (90) located in the reaction chamber (39) between the resilient element (80) and a reaction surface in the cavity. The resilient element (80) may bias the plunger (40) distally relative to the actuator (30), and be compressed when a proximally-directed force is applied to the plunger (40). The force reduction element (90) may dissipate a portion of the proximally-directed force. Related devices and methods are also described.