Tulip Head Collet for Poly Axial Screw Assembly
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Solution Overview
Problem
Poly axial screw systems used in spinal fusion surgery lack rigidity and stability, are difficult to assemble and adjust, and often result in bulky structures that complicate surgery and prolong healing times, with existing connection methods requiring excessive torque and skill for precise positioning.
Innovation Solution
A tulip connector system comprising a head and collet configured to engage with a poly axial screw shaft, allowing for adjustable and stable angular placement, with a tulip fastener that secures the fusion rod to the screw shaft, providing a friction fit and reducing the need for excessive torque during assembly and adjustment.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If poly axial screws use a ball head and U-shaped connector design for flexibility in positioning, then angular placement flexibility is improved, but rigidity and stability during surgery deteriorate
Solution Approach 1:
The connector is designed with a two-stage locking mechanism that transitions from a dynamic, adjustable state during surgery to a static, rigid state after positioning. The set screw allows the connector to be dynamically adjusted to various angles while maintaining stability when tightened, resolving the contradiction between flexibility and rigidity.
2Reliability
If poly axial screw parts are configured for pre-assembly with complex shapes and sizes, then connection security is improved, but device bulk and surgical complexity deteriorate
Solution Approach 1:
The connector is divided into distinct modular components: a U-shaped connector body, a ball head interface, and a set screw mechanism. This segmentation allows each part to have a simple, specific function while collectively providing secure connection, reducing overall surgical complexity.
3Strength
If threaded fasteners are used to secure rods to connectors, then connection strength is improved, but torque requirements and skill dependency deteriorate
Solution Approach 1:
The set screw mechanism is designed to be self-contained and self-explanatory, requiring no additional torque wrench or anti-torque device. The screw directly engages with the connector body, providing inherent mechanical advantage that reduces the torque needed for secure fastening while eliminating the need for specialized tools or techniques.
4Reliability
If bulky poly axial screw structures are used for stability, then connection reliability is improved, but tissue damage and healing time deteriorate
Solution Approach 1:
The connector uses a thin-walled U-shaped design that provides sufficient structural integrity through its geometry and material selection rather than bulk. The optimized wall thickness and cross-sectional shape maintain connection reliability while minimizing the overall size of the implant, thereby reducing tissue damage and facilitating faster healing.
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 tulip connector system enables easy and quick assembly, maintains stable angular placement, reduces tissue damage, and simplifies surgery by providing consistent rigidity and adjustable options without the need for excessive torque, improving surgical precision and reducing healing time.
Implementation Method 1
providing a friction fit and reducing the need for excessive torque during assembly and adjustment
Data Source
AI summary
The present invention generally relates to connectors that connect bone screws with fusion rods for use in stabilizing surgery such as spinal fusion surgery, and to bone screw systems comprising such connectors. In particular, the present invention relates to poly axial screw systems configured to attach the poly axial tulip head after the bone screw has been implanted. Furthermore, embodiments of the present invention relate to tulip connectors which have a hinged joint and a collet that are configured to rotatably and pivotably lock onto the ball head of a poly axial screw shaft. The poly axial tulip head features a collet which can attach to the rod prior to insertion onto the bone screw. The tulip head and rod are then affixed to the bone screw with a nut.