Flexible Instrument Embedded Actuation Conduits
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Solution Overview
Problem
Manufacturing a flexible telerobotic instrument that is small enough to navigate through narrow anatomical passageways while maintaining mechanical structures for remote operation is challenging, as existing instruments often require discrete termination structures for control tendons, leading to kinking and limited durability.
Innovation Solution
The design incorporates embedded conduits within the flexible instrument's wall, allowing control tendons to pass uninterrupted from the proximal to the distal portion, eliminating the need for discrete termination structures and enabling continuous curvature, thereby improving durability and navigation through tortuous anatomical paths.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If discrete termination structures are used for control tendons, then the instrument can be manufactured with simpler construction, but the instrument develops kinking and has limited durability
Solution Approach 1:
The patent merges the conduit structure with the flexible instrument wall by embedding the conduits directly into the wall material. This integration eliminates separate termination structures and creates a unified construction where tendons pass continuously through the wall thickness, resolving the contradiction between manufacturing simplicity and durability.
Solution Approach 2:
The conduits are nested within the flexible wall structure, with tendons nested within the conduits. This nested arrangement allows the tendons to be protected and guided through the wall without requiring external termination structures, improving durability while maintaining manufacturability.
2Device complexity
If discrete termination structures are used for control tendons, then the instrument construction is simpler, but the instrument is prone to kinking and has limited durability
Solution Approach 1:
The conduit termination is merged with the flexible wall by embedding the conduit ends directly into the wall material. This eliminates the need for separate termination components and creates a continuous structural path for tendons, reducing construction complexity while eliminating kinking vulnerabilities.
Solution Approach 2:
The patent creates continuous tendon paths through the flexible wall by embedding conduits that extend through the wall thickness. This continuity eliminates discontinuities that would cause kinking, ensuring smooth tendon movement and improving reliability without significantly increasing construction complexity.
3Length of moving object
If the instrument has a small outer diameter to navigate narrow passageways, then the instrument can access remote tissue locations, but the instrument has limited space for mechanical structures
Solution Approach 1:
The patent nests multiple functional elements within the flexible wall thickness: conduits are embedded within the wall, and tendons are nested within the conduits. This nested arrangement maximizes the use of available space within the small outer diameter, accommodating necessary mechanical structures without increasing the overall instrument size.
Solution Approach 2:
The patent utilizes the wall thickness dimension to accommodate conduits and tendons, rather than requiring additional radial space. By embedding structures within the existing wall volume, the instrument maintains a small outer diameter while providing sufficient space for complex mechanical components.
Data Source
AI summary
A minimally invasive medical instrument comprises an elongate flexible body including a proximal portion, a distal portion, a transition portion between the proximal portion and the distal portion, an inner sheath, and an outer sheath. The medical instrument further comprises a plurality of conduits positioned within the inner sheath. The plurality of conduits extend through the inner sheath and terminate within the inner sheath. Each conduit includes a conduit lumen and a distal end. The distal end terminates at the transition portion. The medical instrument further comprises at least one tendon extending through the conduit lumen of at least one conduit of the plurality of conduits from the proximal portion into the distal portion of the elongate flexible body. The at least one tendon is actuatable to steer the distal portion.