Rotating Snare Coil Retrieval Device for Secure Specimen Capture
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Solution Overview
Problem
Current minimally invasive retrieval devices face challenges in precisely engaging and securely capturing foreign bodies in vascular or nonvascular spaces due to limitations in controlling the geometry and surface area of snare loops or mesh structures, leading to inefficient and unreliable retrieval procedures.
Innovation Solution
A retrieval device with a rotatable inner member and snare coils that can be actuated to open or close, allowing for precise manipulation and increased surface area contact, featuring a design where the snare coils can be interleaved to form a mesh-like structure and include an expandable member for enhanced engagement capabilities.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If standard minimally invasive retrieval devices are used, then the procedure remains minimally invasive, but the ability to precisely engage and securely capture foreign bodies is compromised
Solution Approach 1:
The retrieval device is divided into multiple functional components: an outer cannula, an inner member, and multiple snare coils. Each component has a specific function - the outer cannula provides structural support and containment, the inner member enables rotational control, and the snare coils perform the actual capturing. This segmentation allows each part to be optimized for its specific function while working together as an integrated system, improving capture reliability without requiring excessive overall complexity.
Solution Approach 2:
The snare coils are designed to be dynamically adjustable through rotation of the inner member relative to the outer cannula. This dynamic mechanism allows the operator to open the snare coils for engagement with foreign bodies and then close them for secure capture. The dynamic adjustment capability enables the device to adapt to different capture scenarios, improving reliability while maintaining reasonable structural complexity through a single rotational degree of freedom.
2Measurement precision
If snare loop diameter is reduced for precise engagement, then engagement precision improves, but surface area contact decreases reducing capture security
Solution Approach 1:
The invention transitions from a single-loop snare design to a multi-loop snare coil configuration. This dimensional change allows the device to engage foreign bodies with precise control over individual loop diameters while simultaneously providing a cumulative contact surface area from multiple loops. The multi-loop structure effectively adds another dimension to the engagement geometry, resolving the contradiction between precision and contact area.
Solution Approach 2:
Multiple snare coils are combined in a nested or interleaved configuration, where each coil contributes to both the precision of engagement and the total contact surface area. The coils work together as a unified capturing structure, merging their individual functions to achieve both precise engagement (through controlled loop geometry) and secure capture (through cumulative surface area contact).
3Productivity
If single snare loop design is used, then device simplicity is maintained, but retrieval efficiency decreases in complex spaces
Solution Approach 1:
The retrieval function is segmented across multiple snare coils rather than relying on a single loop. Each coil can independently engage with foreign bodies, and the nested or interleaved configuration allows the coils to work in sequence or simultaneously. This segmentation improves retrieval efficiency in complex vascular or nonvascular spaces by providing multiple engagement opportunities while maintaining a relatively simple overall device structure through the use of identical modular coil units.
4Ease of operation
If rotatable inner member mechanism is added for snare actuation, then manipulation precision improves, but device complexity increases
Solution Approach 1:
The rotatable inner member introduces a single rotational degree of freedom that dynamically controls the opening and closing of all snare coils simultaneously. This dynamic mechanism simplifies operation compared to requiring independent control of multiple loops, as one rotational action actuates the entire snare system. The rotational mechanism provides precise manipulation capability while maintaining reasonable structural complexity through its simplicity and elegance.
Solution Approach 2:
The rotatable inner member serves multiple functions: it acts as the actuation mechanism for opening and closing the snare coils, provides rotational control for positioning, and serves as the structural core around which the snare coils are nested. This multi-functionality reduces the need for separate control mechanisms, improving ease of operation while minimizing the increase in device complexity.
Data Source
AI summary
A retrieval device for retrieving and capturing a foreign body specimen, such as a tissue specimen or a foreign material specimen, according to one exemplary embodiment includes an outer cannula member having an inner lumen and an inner member received within the inner lumen such that the inner member can rotate relative to the outer cannula. The inner member has a distal end that extends beyond a distal end of the outer cannula. The device also includes a first snare coil having a first end and an opposing second end. The first end of the snare coil is attached to an outer surface of the outer cannula and the second end of the snare coil is attached to the inner member to allow the snare coil to be actuated by rotating the inner member relative to the outer cannula so as to either open or close the snare coil for collecting the specimen.