Spinal Implant Auto-Lock Cam Mechanism
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Solution Overview
Problem
Current spinal implant systems for treating spinal disorders require complex instrumentation and high force for assembly, which can put additional stress on vertebrae and complicate surgical procedures, and lack efficient mechanisms for secure attachment of bone fasteners.
Innovation Solution
A modular spinal implant system featuring a bone fastener with an auto-lock mechanism, including a cam lock system that allows for secure connection of a receiver assembly to a bone screw shaft without the need for instrumentation, using a snap ring and spring biasing system to ensure reliable attachment with minimal force.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If complex instrumentation and high force assembly methods are used, then secure attachment of bone fasteners is achieved, but additional stress on vertebrae and surgical procedure complexity increase
Solution Approach 1:
The bone fastener system incorporates an auto-lock mechanism where the cam lock automatically engages with the receiver assembly upon insertion, without requiring external instrumentation or manual intervention. The spring-loaded cam mechanism self-activates to secure the attachment, eliminating the need for complex surgical tools while ensuring reliable fixation.
Solution Approach 2:
The invention replaces complex mechanical instrumentation systems with a simplified cam-based locking mechanism. Instead of requiring external locking tools or multi-step mechanical assembly procedures, the system uses an integrated cam lock that rotates and engages automatically, substituting complex external mechanical systems with a compact self-contained mechanism.
2Reliability
If high force assembly methods are used, then secure attachment of bone fasteners is achieved, but pre-load on vertebrae increases
Solution Approach 1:
The cam lock mechanism transitions from an unlocked to a locked state through a rotational motion that gradually engages the locking surfaces. This dynamic engagement allows the components to settle into their final positions with minimal impact force, distributing the loading more evenly and reducing peak pre-load on the vertebrae compared to direct high-force assembly methods.
Solution Approach 2:
The spring-loaded cam mechanism incorporates a cushioning element that absorbs and distributes the assembly forces. The spring provides a gradual engagement rather than instantaneous hard contact, cushioning the impact and reducing peak forces transmitted to the vertebral bone during the attachment process.
3Reliability
If traditional bone fastener assembly is used, then attachment is achieved, but assembly time and surgical procedure duration increase
Solution Approach 1:
The cam lock mechanism is pre-configured in an unlocked state with the cam positioned to allow easy insertion. Upon insertion of the bone screw into the receiver assembly, the cam automatically rotates into the locked position through the spring mechanism, performing the locking action as a preliminary step that occurs automatically during insertion rather than requiring a separate time-consuming locking step.
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
Enables efficient, low-force assembly of spinal implants, reducing pre-load on vertebrae and enhancing the stability of bone fasteners, thereby facilitating safer and more effective surgical treatments for spinal disorders.
Implementation Method 1
using a snap ring and spring biasing system to ensure reliable attachment with minimal force
Data Source
AI summary
A bone fastener comprises a first member including an inner surface defining an implant cavity and a wall defining a groove. A first element is disposed within the groove. A second member is configured to penetrate tissue and engageable with the first element to dispose the first element in a capture orientation within the groove to connect the members. A second element is engageable with the first element to urge the first element to the capture orientation. Systems, instruments and methods are disclosed.