Monolithic Bone Anchoring Coupling Device via Additive Manufacturing
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Solution Overview
Problem
Conventional coupling devices for polyaxial bone anchoring systems are complex and require separate fixation members, which can lead to increased part count and potential weaknesses in the connection between the receiving part and the locking member.
Innovation Solution
A coupling device with a receiving part and a locking member that are inseparably interconnected, manufactured using additive manufacturing methods such as selective laser sintering or selective laser melting, forming a monolithic unit that can be post-processed to create a secure, integrated unit without external fixation members.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If conventional coupling devices use separate fixation members to connect the receiving part and locking member, then the assembly process is simplified, but the device complexity increases and the connection strength decreases
Solution Approach 1:
The receiving part and locking member are merged into a single monolithic component manufactured using additive manufacturing. This integration eliminates the need for separate fixation members and reduces the total part count while maintaining the functional separation between the receiving part (for receiving the bone anchoring element head) and the locking member (for preventing head removal).
2Ease of manufacture
If separate fixation members are used to connect receiving part and locking member, then the assembly is easier, but the connection strength and force transfer capability are reduced
Solution Approach 1:
By merging the receiving part and locking member into a single monolithic structure, the connection strength is maximized as there are no separate fixation members creating potential weak points. The integrated structure ensures continuous load path and superior force transfer capability between the receiving part and locking member.
Solution Approach 2:
The monolithic coupling device is manufactured using additive manufacturing with metal powders (such as titanium, stainless steel, or cobalt-chromium alloys) that provide high strength and excellent force transfer properties. The additive manufacturing process creates a composite structure with optimized mechanical properties.
3Ease of manufacture
If conventional manufacturing methods are used, then the manufacturing process is simpler, but complex shapes and optimized structures are difficult to achieve
Solution Approach 1:
The manufacturing approach changes from traditional subtractive or assembly-based methods to additive manufacturing, which fundamentally changes the manufacturing paradigm. This allows for the creation of complex internal geometries, optimized structural features, and integrated components that would be impossible or extremely difficult to achieve with conventional manufacturing methods.
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 reduces the number of parts, enhances the strength and force transfer capabilities, and allows for complex shapes that are difficult to manufacture conventionally, resulting in a more reliable and efficient polyaxial bone anchoring system.
Implementation Method 1
The coupling device can be manufactured using an additive manufacturing method, more specifically, an additive layer manufacturing method. In such a method, the coupling device is built up by layer-wise deposition of a building material and solidifying or melting the material in each layer at the cross-section of the coupling device in the respective layer. A suitable method is, for example, selective laser sintering (SLS) or selective laser melting (SLM) in which the building material is a powder, such as a metal powder or a plastic powder, and a laser is used to melt the powder.
Implementation Method 2
A suitable method is, for example, selective laser sintering (SLS) or selective laser melting (SLM) in which the building material is a powder, such as a metal powder or a plastic powder, and a laser is used to melt the powder.
Implementation Method 3
Alternatively, an electron beam may be used to melt the building material.
Implementation Method 4
a laser is used to melt the powder
Implementation Method 5
Alternatively, an electron beam may be used to melt the building material.
Data Source
Figure 1~2
Figure 3
Figure 4~6b
AI summary
A coupling device for coupling a rod to a bone anchoring element is provided, the coupling device (5, 5', 5", 5'") including a receiving part (50, 50', 50", 50"') comprising a head receiving portion (61, 31, 51'; 505) for receiving a head (3) of the bone anchoring element and a rod receiving portion (54, 64; 54', 504) for receiving the rod (100) and a locking member (60, 60', 60", 60'") movable relative to the receiving part (50, 50', 50", 50"') between a first position in which the head (3) is insertable into the head receiving portion (61, 31, 51'; 505) and a second position in which the head (3) is prevented from being removed from the head receiving portion, wherein the receiving part (50, 50', 50", 50'") and the locking member (60, 60', 60", 60'") are inseparably interconnected with each other.