Safety Needle with Retracting Stylet for Organ Injury Control
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Solution Overview
Problem
Current needle decompression devices for tension pneumothorax are prone to iatrogenic injury to underlying organs, clogging, and sharps management issues, with insufficient venting capacity and potential for tissue core plugging, especially in prehospital care settings.
Innovation Solution
A safety needle device with a retracting pen mechanism, featuring a hollow outer cannula with a sharp point and a protective hollow inner tubular stylet, allowing user-controlled exposure or obscuration of the sharp tip, and a plunger mechanism for dislodging tissue plugs, enabling confirmation of correct placement and preventing organ injury, while allowing larger diameters for enhanced fluid flow.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If a sharp needle is used for needle decompression, then initial penetration through the chest wall is effective, but the possibility of damaging underlying organs increases
Solution Approach 1:
The needle is divided into two functional segments: an outer cannula with a sharp tip for penetration and an inner stylet with a blunt tip for safe organ contact. This segmentation allows the sharp outer needle to penetrate quickly while the blunt inner stylet protects organs during insertion and remains exposed after penetration to prevent damage
Solution Approach 2:
Instead of keeping the sharp tip exposed throughout use, the design inverts the protection logic: the blunt inner stylet is initially exposed to protect organs during penetration, then the sharp outer tip is exposed only during the brief penetration moment, and finally the blunt inner stylet is exposed again for safe catheter advancement and organ protection
2Object-affected harmful factors
If a small inner diameter needle (14 gauge) is used, then organ damage risk is reduced, but venting capacity for pressurized air is insufficient
Solution Approach 1:
The inner diameter is made dynamic through the movable inner stylet mechanism. The needle can switch between a smaller effective diameter (when inner stylet is exposed for organ protection) and a larger effective diameter (when inner stylet is retracted for enhanced venting). This dynamic adjustment allows the same needle to provide both organ protection and adequate venting capacity for tension pneumothorax relief
3Productivity
If a larger gauge needle (10 gauge) is used to permit greater flow, then venting capacity is improved, but the propensity to clog with tissue core increases
Solution Approach 1:
The blunt inner stylet is positioned to be exposed before penetration occurs. This preliminary exposure of the blunt stylet allows it to lead the way through tissue, preventing tissue cores from being wedged into the needle lumen. The blunt stylet effectively clears a path ahead of the larger diameter outer cannula, maintaining reliability while allowing greater flow capacity
4Productivity
If the needle is left in place for long periods, then better flow is achieved, but the risk of open pneumothorax and kinking increases
Solution Approach 1:
The device is designed as a disposable single-use item. The safety needle with its protective blunt inner stylet provides adequate flow capacity for the critical initial decompression period. After use, the entire device is discarded rather than left in place, eliminating the long-term risks of open pneumothorax and kinking while providing sufficient flow for the emergency situation
5Ease of operation
If the sharp tip is exposed for effective penetration, then initial insertion is successful, but iatrogenic injury to underlying organs occurs
Solution Approach 1:
The needle is divided into two functional segments: an outer cannula with a sharp tip for penetration and an inner stylet with a blunt tip for safe organ contact. This segmentation allows the sharp outer needle to penetrate quickly while the blunt inner stylet protects organs during insertion and remains exposed after penetration to prevent damage
Solution Approach 2:
Instead of keeping the sharp tip exposed throughout use, the design inverts the protection logic: the blunt inner stylet is initially exposed to protect organs during penetration, then the sharp outer tip is exposed only during the brief penetration moment, and finally the blunt inner stylet is exposed again for safe catheter advancement and organ protection
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 device effectively prevents iatrogenic injury, ensures safe needle placement, and facilitates easy management of tissue plugs, providing effective decompression with reduced risk of clogging and sharps hazards, enhancing safety and efficiency in emergency situations.
Implementation Method 1
Enclosed within the outer cannula is a hollow tube that has a blunt tip at its distal end (common to the sharp tip of the outer cannula), and that is axially spring-biased in a distal direction by a spring contained in the plastic housing. When no force is applied to the distal end to resist the penetrating point, the spring bias forces the hollow inner tube to protrude just beyond the sharp tip of the outer cannula
Implementation Method 2
A safety needle device with a retracting pen mechanism, featuring a hollow outer cannula with a sharp point and a protective hollow inner tubular stylet, allowing user-controlled exposure or obscuration of the sharp tip, and a plunger mechanism for dislodging tissue plugs
Data Source
AI summary
A medical device including a portion similar to a Veress needle, useful for relief of tension pneumothorax. The device includes a hollow tubular stylet disposed movably within a hollow needle or cutting cannula, and an optionally releasable locking mechanism for keeping the stylet in place protruding distally beyond the sharpened distal end of the cutting cannula to prevent puncture of internal organs after the chest wall has been intentionally punctured. The stylet can also be moved outward from within the cannula to push a plug of tissue from the bore of the cannula. A valve or a connector for a tube may be provided at a proximal end of the stylet.