Bone Anchor Receiving Part Lateral Locking Mechanism
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Solution Overview
Problem
Existing bone anchoring devices are large in size and lack a modular system, making them unsuitable for applications like cervical spinal surgery and pediatric use, where smaller and more versatile solutions are required.
Innovation Solution
A compact bone anchoring device with a receiving part that uses a locking ring to clamp the head of the bone anchoring element laterally, reducing the device's height and outer diameter, and allowing for modular use with various receiving parts and bone anchors, facilitating easier handling and adjustment.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a locking collar and top locking nut are used to secure the rod, then reliable locking is achieved, but the device size increases significantly
Solution Approach 1:
The locking ring integrates multiple functions into a single component: it provides lateral compression to secure the head, prevents rotation through its circumferential design, and secures the rod through the receiving part. This eliminates the need for separate locking collars and top locking nuts, significantly reducing device size while maintaining locking reliability.
Solution Approach 2:
Instead of using a traditional top-down locking mechanism with a locking collar and nut that extend outward, the invention uses a lateral compression approach where the locking ring compresses the head from the sides and secures the rod from below through the receiving part. This inverted approach reduces the outward extension and overall device footprint.
2Ease of operation
If a locking collar is placed onto the coupling element from above, then the head can be locked, but the device becomes complex and difficult to secure against escaping and rotation
Solution Approach 1:
The locking ring is placed from below rather than from above, fundamentally changing the assembly sequence and securing mechanism. This inversion simplifies the operation by eliminating the need to navigate over complex structures and provides inherent security against escaping and rotation through its circumferential design that engages with the receiving part.
Solution Approach 2:
The locking ring's circumferential design with the receiving part creates self-securing features that prevent escaping and rotation automatically upon installation. The structure itself provides the security mechanisms without requiring additional components or complex assembly steps, making the device easier to operate and more reliable.
3Volume of stationary object
If the locking ring height is reduced to minimize device profile, then device dimensions are reduced, but the clamping force may be insufficient
Solution Approach 1:
The locking ring applies concentrated local pressure at the compression zone where it contacts the head, maximizing clamping force in a small volume. This localized quality approach allows the locking ring to be short while still generating sufficient clamping force through focused compression rather than distributing force over a larger height.
Solution Approach 2:
The system uses the composite interaction between the locking ring, head receiving portion, and head to achieve high clamping force. The combination of these components creates a mechanical advantage where the locking ring's compression is amplified through the head receiving portion's geometry, allowing reduced locking ring height while maintaining sufficient clamping strength.
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 safe and secure locking mechanism with reduced force requirements, enabling smaller device dimensions suitable for minimal open applications and allowing for modular system integration, enhancing usability in small-sized surgical contexts.
Implementation Method 1
The head of the bone anchoring element is locked in the receiving part by compression of a head receiving portion of the receiving part laterally surrounding the head by means of a locking ring
Implementation Method 2
The locking ring has an interior surface with a curved portion, which presses against the curved portion of the exterior surface of the head receiving portion to compress the head receiving portion so that the head is clamped
Data Source
Figure 1~2
Figure 3~4
Figure 5~9
AI summary
A receiving part for receiving a rod for coupling the rod to a bone anchoring element is provided, the receiving part including a receiving part body (5, 5') with a rod receiving portion (9) with a channel (12) for receiving the rod, and a head receiving portion (16) for accommodating a head (3, 30) of the bone anchoring element, the head receiving portion having an open end (17) and being flexible so as to allow introduction and clamping of the head, the head receiving portion having an exterior surface with a curved portion; and a locking ring (8, 8', 8") embracing the head receiving portion (16), and wherein the locking ring has an interior surface with a curved portion (8a), which presses against the curved portion of the exterior surface of the head receiving portion (16) to clamp the head.