Endoscope Sheath with Radially Expandable Members for Ureteral Stone Retrieval
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Solution Overview
Problem
During ureteroscopy procedures, small stone fragments often remain in the kidney due to difficulties with conventional stone baskets, and there is a risk of ureter perforation or avulsion, which can lead to complications such as loss of the renal unit.
Innovation Solution
A sheath capable of receiving an endoscope insertion tube with radially expandable flexible members that expand during fluid inflow, creating isolated spaces for irrigation and debris removal, reducing the risk of ureter perforation and aiding in the retrieval of small stone fragments.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If conventional stone baskets are used to capture stone fragments, then large fragments can be removed, but small fragments remain in the kidney due to capturing difficulties
Solution Approach 1:
The sheath is divided into multiple segments including radially expandable flexible members that can be independently positioned. These segmented structures create multiple isolated spaces along the sheath length, allowing simultaneous capture and irrigation in different regions, thereby improving both small fragment capture and overall removal efficiency
Solution Approach 2:
The sheath acts as an intermediary device between the endoscope and the kidney stones. It provides a protected environment with controlled fluid dynamics, using the expandable members as intermediaries to gently capture small fragments while irrigation fluid flows through isolated spaces to prevent clogging and facilitate complete retrieval
2Productivity
If force is applied to remove stone fragments, then fragments can be retrieved, but ureter perforation or avulsion may occur
Solution Approach 1:
The radially expandable flexible members provide beforehand cushioning by creating a compliant, expandable structure that gently engages stone fragments. The flexible nature of these members cushions against the delicate ureter tissue, preventing perforation while still enabling effective fragment capture and retrieval
Solution Approach 2:
The sheath employs flexible members made of compliant materials that can adapt to the ureter's natural contours. These flexible structures reduce stress concentration and distribute forces evenly, minimizing the risk of ureter avulsion or perforation during fragment retrieval operations
3Productivity
If irrigation fluid is used to remove debris, then stone fragments can be flushed out, but fluid flow may cause ureter damage
Solution Approach 1:
The irrigation system is segmented into multiple isolated spaces created by the radially expandable flexible members. This segmentation allows controlled fluid flow through specific channels, directing irrigation away from vulnerable ureter areas while maintaining effective debris removal capability through distributed flow paths
Solution Approach 2:
The sheath utilizes hydraulic principles to control fluid flow through the isolated spaces. By regulating pressure and flow rates through the expandable members, the system achieves effective debris removal while maintaining safe fluid dynamics that prevent ureter tissue damage from excessive pressure or velocity
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 sheath effectively irrigates and removes debris from the ureter, reducing the risk of ureter perforation and improving the retrieval of small stone fragments, thereby enhancing the efficacy of ureteroscopy procedures.
Implementation Method 1
The plurality of radially expandable flexible members may expand during active fluid inflow
Data Source
AI summary
A sheath includes a sheath body, an inflow port at a proximal end of the sheath body, an outflow port at the proximal end of the sheath body, and a plurality of radially expandable flexible members which extend along a length of the sheath body. The plurality of radially expandable flexible members are attached to the sheath body at a plurality of anchor points along the length of the sheath body. The plurality of radially expandable flexible members expand during active fluid inflow. The radially expandable flexible members are spaced apart along the sheath body to define one or more isolated spaces that extend between adjacent radially expandable flexible members when the radially expandable flexible members are inflated within a body passage.