Multi-Position Locking Ring for Bone Anchoring
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Solution Overview
Problem
Existing bone anchoring devices face challenges in providing a compact design while ensuring safe and secure locking during surgery, particularly in applications like cervical spinal surgery and pediatric procedures, where smaller sizes are required, and there is a need for safer handling and reduced risk of inadvertent movement or removal of the bone anchoring elements.
Innovation Solution
A receiving part with a locking ring that can be arranged in three positions: an insertion position, a pre-locking position to prevent inadvertent removal and movement, and a locking position, using a single locking ring to achieve secure clamping of the bone anchoring element's head, which reduces the number of elements, minimizes manufacturing costs, and allows for a smaller device size by applying pressure circumferentially from the lateral sides.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If multiple locking elements are used to ensure secure locking and safe handling, then reliability is improved, but device complexity increases
Solution Approach 1:
The patent combines multiple locking functions into a single locking ring that can occupy different positions (first position for insertion, second position for pre-locking, third position for final locking). This single element performs what would traditionally require multiple separate locking components, thereby reducing device complexity while maintaining reliability through the multi-position locking mechanism.
2Volume of moving object
If a compact design is used to reduce device size for minimally invasive applications, then ease of operation is improved, but reliability may worsen due to space constraints for locking mechanisms
Solution Approach 1:
The patent utilizes the axial dimension (along the rod axis) to create multiple locking positions rather than relying solely on radial space. The locking ring can move along the axis to occupy different positions (insertion, pre-locking, final locking), which allows a compact radial design while maintaining reliable locking functionality through axial displacement. This dimensional approach enables secure locking in a compact overall device size.
3Ease of manufacture
If a single locking ring is used to reduce device complexity, then ease of manufacture is improved, but the ability to provide both pre-locking and final locking functions may worsen
Solution Approach 1:
The locking ring is designed as a dynamic element that can occupy at least three different axial positions along the rod axis. This dynamic multi-position capability allows a single static component to perform multiple locking functions (insertion, pre-locking, final locking) that would otherwise require multiple separate components. The versatility is achieved through the ring's ability to be positioned and locked at different locations along its travel path.
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 safer handling and secure locking of the bone anchoring device during surgery, reduces the force required for clamping, and allows for a modular system with various bone anchors, making it suitable for minimally invasive applications by maintaining a compact size and preventing jamming issues.
Implementation Method 1
The head of the bone anchoring element is locked in the receiving part body by compression of a head receiving portion of the receiving part laterally surrounding the head by means of the locking ring
Data Source
AI summary
A receiving part for coupling a rod to a bone anchoring element includes a receiving part body including a rod receiving portion having a channel for receiving a rod, and a head receiving portion for accommodating a head of a bone anchoring element, the head receiving portion having an open end and being flexible for inserting and clamping of the head; and a locking ring around the head receiving portion, wherein in a pre-locking position, a spring portion on one of the locking ring or the receiving part body engages a corresponding portion on the other one of the locking ring or the receiving part body, and the locking ring exerts a first force onto the head receiving portion, and wherein in a locking position, the locking ring exerts a second force greater than the first force onto the head receiving portion to lock the head therein.