Self-Adjusting Spring Locking Mechanism for Spinal Rod Fixation
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Current spinal fixation systems face challenges with bulky components that cause soft tissue irritation and require complex instrumentation due to the need for torque wrenches and threaded locking mechanisms, which can lead to cross-threading and increased surgical difficulty.
Innovation Solution
A non-threaded, self-adjusting spring locking mechanism that biases a rod against a rod seat within a screw and rod fixation assembly, eliminating the need for torque wrenches and reducing the overall height of the implant assembly by using a spring-based locking system that self-adjusts to exert a controlled locking force without mechanical losses.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a threaded locking mechanism with nut and connector is used to secure the rod, then the rod can be securely locked to the implant, but the overall height of the implant assembly increases and bulky components cause soft tissue irritation
Solution Approach 1:
The patent removes the nut and connector components from the implant assembly, extracting only the essential locking function. The rod is locked directly against the implant body through a tapered interface and friction, eliminating the need for external locking components that increase height and cause soft tissue irritation.
Solution Approach 2:
The patent replaces the threaded mechanical locking system with a friction-based tapered interface system. The taper creates mechanical interlocking through friction and geometric constraint, substituting the nut-and-thread mechanism with a more compact design that reduces overall assembly height.
2Length of stationary object
If a tapered locking mechanism without threads is used, then the overall height is reduced and soft tissue irritation is minimized, but the locking mechanism requires complex instrumentation and torque wrenches for proper engagement
Solution Approach 1:
The tapered interface design allows the rod to self-align and self-lock through its geometric shape. The taper angle and friction characteristics enable automatic engagement without requiring precise torque control or complex instrumentation, making the system self-servicing during implantation.
Solution Approach 2:
The patent optimizes the taper angle and surface friction characteristics to achieve proper locking without requiring complex instrumentation. By adjusting these parameters, the system achieves reliable locking through simple push-in or tap-in actions, eliminating the need for torque wrenches and complex engagement procedures.
3Reliability
If threaded locking components are used, then secure rod attachment is achieved, but cross-threading risks and surgical difficulty increase
Solution Approach 1:
The patent replaces the threaded connection system with a tapered friction-based locking mechanism. This substitution eliminates threads entirely, removing the risk of cross-threading and the need for precise threading alignment, while maintaining secure rod attachment through geometric constraint and friction.
Solution Approach 2:
The tapered interface provides self-aligning properties that guide the rod into proper engagement without requiring precise manual alignment or threading. The geometric constraint of the taper automatically positions the rod correctly, making the locking operation simple and error-free during surgery.
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 solution provides a secure, compact, and efficient locking mechanism that minimizes soft tissue irritation, reduces surgical complexity, and maintains known tolerances, eliminating the need for torque wrenches and threaded locking, thereby simplifying the instrumentation and reducing the risk of cross-threading.
Implementation Method 1
a biasing device seated in the biasing device seat for biasing a rod against a rod seat
Data Source
AI summary
A locking mechanism including a non-threaded, self-adjusting locking device for locking a rod in place within a screw and rod assembly. A non-threaded, self-adjusting locking device for locking a rod in place within a screw and rod assembly. A spring for locking a rod in a screw and rod fixation assembly. A assembly including an implant body including a rod seat for seating a rod therein, a biasing device seat for seating a biasing device therein, and a biasing device seated in the biasing device seat for biasing a rod against a rod seat. A method of biasing a rod against a rod seat in a screw and rod fixation assembly.