Polyaxial Bone Anchoring Device Sequential Locking Mechanism
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Solution Overview
Problem
Current polyaxial bone anchoring devices require multiple tools and complex procedures for securing the head and rod, leading to cumbersome handling and unreliable fixation.
Innovation Solution
A polyaxial bone anchoring device with a single-tool, single-drive locking mechanism using a deformable locking member that sequentially clamps and locks the head and rod, allowing for adjustable clamping force and easy revision.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If multiple locking elements and tools are used to secure the head and rod, then the fixation reliability is improved, but the device complexity and ease of operation deteriorate
Solution Approach 1:
The patent combines multiple locking functions into a single locking member that can sequentially clamp and lock both the head and the rod. This merging of functions reduces the number of separate locking elements and tools needed, thereby reducing device complexity while maintaining fixation reliability through the integrated sequential locking mechanism.
Solution Approach 2:
The single locking member is designed to perform multiple functions: it can clamp the head, clamp the rod, and lock both components in sequence. This multi-functionality eliminates the need for separate specialized tools for each locking step, addressing the contradiction between reliability and device complexity.
2Manufacturing precision
If multiple tools with multiple drive portions are used, then the locking precision is improved, but the ease of operation deteriorates
Solution Approach 1:
The patent merges multiple drive portions into a single drive portion that engages the locking member. This single drive portion controls the sequential clamping and locking of both the head and rod, maintaining locking precision while significantly improving ease of operation by reducing the number of tools required.
Solution Approach 2:
The locking member is designed with a deformable first portion that dynamically adapts during the locking process. The deformable section allows the single drive portion to control the sequential locking mechanism, ensuring precise clamping and locking while simplifying the operation to a single tool action.
3Reliability
If a complex sequential locking procedure is used, then the fixation reliability is improved, but the loss of time increases
Solution Approach 1:
The sequential locking mechanism allows continuous action through a single locking member that performs multiple locking steps in sequence without requiring tool changes or interruptions. The deformable first portion enables continuous deformation and locking action, maintaining reliability while reducing the time loss associated with multiple separate locking procedures.
Solution Approach 2:
The locking member is designed with pre-configured deformable sections that automatically engage and deform in the correct sequence during insertion. This preliminary configuration of the locking mechanism ensures reliable sequential locking while minimizing the time required for the procedure, as the sequence is built into the component design rather than requiring complex manual coordination.
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
Facilitates simplified and reliable fixation of the head and rod with reduced parts, enabling efficient sequential locking and adjustment, and allows for revisions without additional tools.
Implementation Method 1
first the deformable first portion comes into contact with the pressure member and is deformed resulting in a load applied to the pressure member
Implementation Method 2
a load applied to the pressure member that clamps the head
Implementation Method 3
thereafter the second portion comes into contact with the rod and clamps the rod
Data Source
AI summary
A polyaxial bone anchoring device is provided comprising a bone anchoring element having a shank to be anchored in the bone and a head; a receiving part coupled to the shank and configured to pivotably receive the head, and having a channel for receiving a rod and a longitudinal axis; a pressure member arranged in the receiving part and configured to exert pressure onto the head to lock the head; a locking member that is insertable into the channel, the locking member comprising a top end and a bottom end facing the pressure member; a deformable first portion and a second portion provided at the bottom end; wherein, when the locking member is advanced into the channel along the longitudinal axis the deformable first portion is deformed resulting in a load applied to the pressure member that clamps the head, and the second portion clamps the rod.