Sheath with Conical Tips for Reduced Insertion Trauma
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Current guidewire sheath designs require significant axial force for insertion due to radial discontinuities at the ends of the inner and outer plastic tubes, leading to trauma and difficulty in accessing blood vessels.
Innovation Solution
The sheath design features inner and outer sheath members with pointed tips having conical surfaces and beveled ends, reducing the force required for insertion by distributing radial deformation along the length of the tips, allowing for easier penetration and minimizing trauma.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If the inner and outer plastic tubes are designed with circular ends in a stepped axial arrangement, then the sheath structure is simple and easy to manufacture, but significant axial force is required for insertion causing trauma to the patient
Solution Approach 1:
The patent applies local quality by modifying only the distal ends of the inner and outer sheath members to have tapered or contoured shapes, while the rest of the sheath maintains its simple cylindrical structure. This localized modification reduces insertion trauma without complicating the overall manufacturing process.
Solution Approach 2:
The tapered or contoured distal ends are pre-formed during manufacturing to create a gradual transition zone before insertion. This preliminary shaping action prepares the sheath to distribute radial deformation along the length of the tapered portion, reducing the peak axial force required during insertion.
2Force
If the distal ends of the inner and outer sheath members are modified with tapered or contoured shapes, then insertion force is reduced and trauma is minimized, but the manufacturing process becomes more complex
Solution Approach 1:
The complex tapered or contoured shapes are applied only to the distal ends of the sheath members, leaving the majority of the sheath structure as simple cylinders that are easy to manufacture. This minimizes the impact on overall manufacturing complexity while achieving the force reduction benefit.
Solution Approach 2:
The patent modifies specific geometric parameters (taper angle, contour shape, length of tapered portion) to optimize the balance between insertion force reduction and manufacturing feasibility. By carefully selecting these parameters, the design achieves trauma reduction without requiring excessively complex manufacturing processes.
3Reliability
If the inner sheath member is made slightly larger than the guidewire outer diameter to prevent dislodgement, then guidewire retention is improved, but the radial discontinuity at the step increases requiring more insertion force
Solution Approach 1:
The patent creates a localized tapered or contoured transition zone at the distal end of the inner sheath member that gradually bridges the radial gap between the guidewire and sheath. This localized modification maintains the slight size difference for retention while eliminating the abrupt radial discontinuity that causes high insertion forces.
Solution Approach 2:
The contoured or tapered distal end creates a curved transition surface that smoothly connects the guidewire diameter to the inner sheath member outer diameter. This curvature eliminates the sharp radial step, distributing the deformation along the curved surface and reducing the peak insertion force required.
Data Source
AI summary
A sheath shaped and dimensioned for reducing trauma and easing insertion thereof includes an inner sheath member shaped and dimensioned to fit around a guidewire in a manner permitting relative movement, the inner sheath member including an inner sheath tip having a primary bevel and a circumferential conical surface. The sheath also includes an outer sheath member shaped and dimensioned to fit around the inner sheath member in a manner permitting relative movement. The outer sheath member includes an outer sheath tip having a primary bevel and a circumferential conical surface.