Slotted Wire Tissue Marker with Pre-bent Distal Sections
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Solution Overview
Problem
Existing surgical marking instruments face challenges in achieving simple and reliable handling, precise tissue marking, high restraining force, ease of use, and cost-effectiveness, with manufacturing tolerances often affecting their performance.
Innovation Solution
A surgical instrument featuring a longitudinally displaceable element formed by a wire with a longitudinal slot, allowing for a single-piece distal region and pre-bending that reduces fatigue, combined with a handle and slide mechanism for improved handling and positioning, and made from materials like nitinol and titanium alloys for enhanced properties.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If the longitudinally displaceable element is formed by individual wires twisted together with pre-bent distal end sections, then the wire can be advanced in the hollow needle, but the handling properties are heavily dependent on manufacturing tolerances and production is not easy
Solution Approach 1:
The patent merges multiple individual wires into a single wire structure with a longitudinal slot. This single wire is then slit in the longitudinal direction to create distal end sections that can bend independently, combining the advantages of a unified structure with the functionality of separate bending elements, thereby improving both manufacturability and handling reliability
Solution Approach 2:
The single wire is segmented by a longitudinal slot that extends from the proximal end toward the distal end, creating separate distal end sections that can bend independently. This segmentation allows each section to function independently while maintaining the structural integrity of the entire wire, reducing dependence on manufacturing tolerances
2Force
If the pre-bending of distal end sections begins at the base of the longitudinal slit, then the anchoring force in tissue is maximized, but fatigue occurs in the area of the foot point of the longitudinal slot
Solution Approach 1:
The patent applies local quality by creating an unbent section at the base of the longitudinal slot where the wire transitions from the slot to the pre-bent distal end sections. This localized unbent region acts as a stress relief zone, preventing fatigue at the critical foot point while maintaining the pre-bending and anchoring force at the distal end sections
3Reliability
If the diameter of the lumen is not significantly larger than the outside diameter of the elongate member in its stretched state, then the wire can be held securely, but the longitudinally displaceable element is difficult to advance in the hollow needle
Solution Approach 1:
The patent utilizes the flexibility of the slotted wire structure, which can deform elastically as it is advanced through the lumen. The longitudinal slot allows the wire to flex and compress slightly during advancement, enabling it to pass through a lumen with minimal clearance while maintaining secure holding when deployed
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 instrument provides improved handling, reduced manufacturing tolerance sensitivity, and enhanced anchoring in tissue with secure curvature, while being cost-effective and compatible with magnetic resonance imaging.
Implementation Method 1
The longitudinally displaceable element has distal end sections which are pre-bent in such a way that they are elastically prestressed in the stretched state and curve in the relaxed state
Implementation Method 2
The pre-bending of the distal end sections causes them to curve in the direction determined by the pre-bending when they emerge from the open mouth of the lumen and in this way are anchored in the tissue to be marked
Data Source
Figure 1
Figure 2a)~2g)
Figure 3
AI summary
The instrument has a hollow needle (12) for piercing into the body tissue, and a longitudinally movable unit guided into the lumen (16). Distal end sections (26, 28) are provided with a bending, such that the end sections are elastically pre-stressed in an elongated condition and twisted in a relaxed condition. The longitudinally movable unit is formed from a wire (14) with a longitudinal slit (22) that extends from a base point at its proximal slit end up to an opened distal slit end. The end sections are separated from each other, where the needle is made from plastic.