Tapered Curved Needle Assembly to Reduce Trauma and Wire Snagging
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Solution Overview
Problem
Existing medical needles face challenges in minimizing tissue damage and scarring while maintaining pushability, and guidewires risk snagging on the needle's distal end during retraction, necessitating improved design for safer and more effective medical procedures.
Innovation Solution
The needles are designed with a distal portion having a smaller diameter than the proximal portion, a tapered intermediate portion for smooth transition, and a guidewire configuration with a smooth core-coil transition and a catheter insert with a resilient shield to protect the guidewire during retraction, enhancing patient safety and preventing snagging.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If the needle distal diameter is reduced to minimize tissue damage, then tissue trauma is decreased, but needle pushability deteriorates
Solution Approach 1:
The needle employs different diameters at different locations: a larger proximal diameter (14-18 gauge) for adequate pushability and structural integrity, and a smaller distal diameter (18-22 gauge) for minimized tissue damage. This local variation in geometric properties allows each section of the needle to optimize its function for the specific requirements at that location.
Solution Approach 2:
The needle shaft is divided into distinct segments: a proximal portion with constant larger diameter, a distal portion with constant smaller diameter, and an intermediate portion with tapered transition. This segmentation allows independent optimization of each segment's properties to balance pushability and tissue trauma reduction.
2Ease of operation
If the needle distal end is made sharp for easy penetration, then penetration ability is improved, but guidewire snagging risk increases
Solution Approach 1:
A radiused heel is provided at the distal end of the needle, transitioning from the sharp tip to the shaft. This radiused portion acts as a cushioning transition zone that prevents the guidewire from snagging on the sharp distal end during retraction, while the sharp tip maintains penetration ability.
Solution Approach 2:
The guidewire is pre-coated with a lubricious substance before insertion, creating a protective layer that reduces friction and prevents snagging on the needle's distal end during both insertion and retraction operations.
3Ease of operation
If a lubricious coating is applied to the needle to reduce friction, then insertion ease is improved, but coating uniformity becomes difficult to maintain
Solution Approach 1:
The lubricious coating is applied to the guidewire before insertion into the needle, rather than coating the needle itself. This preliminary application ensures uniform coating distribution on the guidewire surface, and the coating is maintained throughout the procedure without the manufacturing difficulties associated with coating tapered or curved needle surfaces.
Data Source
AI summary
A needle includes a hub and an elongate body. The elongate body has a proximal portion joined to the hub and defining a proximal end, a distal portion opposite the proximal portion and defining a distal end, and an intermediate portion between the proximal portion and the distal portion and having a first end adjacent the proximal portion and a second end adjacent the distal portion. A lumen extends longitudinally through the elongate body. The proximal portion extends linearly along a longitudinal axis and has a proximal diameter. The distal portion is curved to space the distal end away from the longitudinal axis and has a distal diameter that is less than the proximal diameter. The intermediate portion tapers in outer diameter going from the first end to the second end.