Polyaxial Ball-and-Socket Fastener With Audible Ring Locking
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Solution Overview
Problem
Current spinal fixation systems require a large inventory of variously sized implants due to the non-uniform strength and position of bone structures, making it difficult for surgeons to find the appropriate anchoring devices during surgery, and often necessitate angular insertion and oversized threads to secure the screws effectively.
Innovation Solution
A modular, bottom-loading polyaxial ball and socket joint fixation system with a U-shaped connector assembly that includes a ring containment slot and a spring-loaded saddle, allowing for snap-together assembly and secure attachment of a spherical ball connector, reducing the need for multiple inventory items by using a retainer ring that expands within the containment slot and returns to a locking position, preventing detachment.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a large inventory of various sized implants is maintained to accommodate non-uniform bone structures, then the surgeon can find appropriate anchoring devices, but the device complexity and inventory management burden increase
Solution Approach 1:
The connector assembly is designed with a universal polyaxial ball and socket mechanism that can accommodate anchoring devices of various sizes and angles through a single standardized interface. The movable saddle and adjustable locking mechanism allow the same connector assembly to adapt to different bone conditions without requiring multiple specialized devices in inventory.
Solution Approach 2:
The connector assembly incorporates a movable saddle that can adjust its position and angle dynamically to match the insertion angle of the anchoring device. This dynamic adjustment capability, combined with the polyaxial design, allows the system to adapt to varying bone structures while maintaining a simplified inventory of standardized components.
2Object-affected harmful factors
If angular insertion is required to avoid muscles and nerves, then the surgeon can reduce surgical trauma, but the device complexity increases due to the need for angular adjustment mechanisms
Solution Approach 1:
The movable saddle is designed to move along the spherical ball connector and lock at various angular positions, enabling angular insertion to avoid muscles and nerves. This dynamic adjustment mechanism allows surgeons to optimize insertion angles while the locking ring provides stable fixation once the desired angle is achieved, reducing surgical trauma without excessive complexity.
Solution Approach 2:
The connector assembly allows change in the angular parameter of insertion through the movable saddle mechanism. By adjusting the angle of the saddle relative to the anchoring device, the system accommodates different insertion angles needed to avoid critical structures, transforming a fixed-parameter design into a variable-parameter solution that reduces harm.
3Strength
If oversized threads are used to achieve suitable bone purchase, then the anchoring strength increases, but the device complexity and potential bone damage increase
Solution Approach 1:
The standardized connector assembly with polyaxial ball and socket interface can accommodate anchoring devices with different thread sizes and configurations. This universal interface allows the use of appropriately sized threads for each specific bone condition without requiring multiple types of connector assemblies, achieving suitable bone purchase while maintaining inventory simplicity.
4Reliability
If a locking ring mechanism is used to secure the spherical ball connector, then the connection reliability increases, but the device complexity increases due to additional components
Solution Approach 1:
The locking ring mechanism is designed to be self-securing through spring-loaded engagement with the connector assembly. Once the spherical ball connector is inserted and the desired angle is achieved, the locking ring automatically engages and secures the connection without requiring additional fastening steps or complex mechanisms, achieving high reliability with minimal added complexity.
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
This system allows for efficient and secure attachment of anchoring assemblies to stabilizing rods, reducing the inventory requirements and providing a reliable, audible, and tactile locking mechanism, ensuring consistent angular positioning and minimizing surgical trauma.
Implementation Method 1
A spring loaded saddle moves the locking ring from a locking ring slot into a ring containment slot
Implementation Method 2
the retainer ring expands. The ring containment slot allows only the horizontal displacement of the retainer ring... the locking ring returns to the locking ring slot and the retainer ring remains in the ring containment slot
Data Source
AI summary
A bottom loading fastening system that consists of the polyaxial ball and socket joint used in conjunction with an anchoring bone screw. The system allows attachment of a connector assembly to the anchoring bone screw having a spherical ball connector using a locking ring positioned in a locking ring slot. Upon installation, the locking ring is moved to a ring containment slot to expand a retainer ring, allowing passage of a bone screw spherical ball, the retainer ring forcing the locking ring back to the locking ring slot, thereby permanently attaching the connector assembly to the anchoring bone screw. Movement of the locking ring from the ring containment slot provides an audible sound and tactile indication that the locking ring has secured the connector assembly to the bone screw.