Variable Stiffness Flexible Elongate Device for Tortuous Anatomy
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Solution Overview
Problem
Flexible elongate devices used in minimally invasive medical procedures often face challenges in maintaining a contorted position within the human anatomy, as forces exerted during insertion tend to straighten articulated portions, compromising the safety and efficacy of the procedure.
Innovation Solution
A system comprising an elongate device with segments that can transition between rigid and flexible states, monitored by a processor to maintain the desired pose during insertion, utilizing stiffening mechanisms such as nitinol wires or balloons to alter rigidity along its length, ensuring stable delivery of instruments through tortuous anatomical paths.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If the elongate device is made flexible to navigate tortuous anatomical paths, then it can be inserted through restricted openings, but it cannot maintain a contorted position and tends to straighten under insertion forces
Solution Approach 1:
The elongate device is divided into multiple segments along its length, where each segment can independently change its rigidity state. This allows different portions of the device to have different mechanical properties - proximal segments remain flexible for navigation while distal segments can be stiffened to maintain position, resolving the contradiction between navigability and position stability.
Solution Approach 2:
The device incorporates dynamic stiffening mechanisms (such as expandable balloons or deployable struts) that can transition between compressed and expanded states. These mechanisms allow the device to adapt its rigidity in real-time based on operational needs - flexible during insertion, rigid during position maintenance - thereby resolving the contradiction between flexibility for navigation and stability for position holding.
2Stability of the object's composition
If stiffening mechanisms are added to maintain device pose, then position stability improves, but device complexity increases
Solution Approach 1:
The stiffening mechanisms are integrated directly into the existing structural elements of the elongate device, combining the support function with the structural framework. This merging approach provides position stability while minimizing additional complexity, as the stiffening elements become part of the device's inherent structure rather than separate add-on components.
Solution Approach 2:
Stiffening mechanisms are selectively applied only to specific segments of the device where position maintenance is needed, rather than making the entire device rigid. This localized approach provides necessary stability while preserving flexibility in other regions, thereby achieving position stability without proportionally increasing overall device complexity.
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 system effectively maintains the contorted position of flexible elongate devices, preventing buckling and ensuring safe and effective delivery of medical instruments by dynamically adjusting rigidity in response to anatomical constraints, thereby enhancing the safety and efficiency of minimally invasive procedures.
Implementation Method 1
each of the plurality of segments includes a stiffening mechanism to alter rigidity of the each of the plurality of segments
Data Source
AI summary
The following describes various applications and uses for a controllably rigidizable flexible, device or sheath, Such rigidizing mechanisms can allow for a transition between a rigid state and a flexible state of a sheath. Rigidization can be applied along an entire length of a flexible sheath or along select portions of the sheath, and the rigidization can be of varying stiffness. Rigidization can be user controlled or automatically controlled using computer processes.