Polyaxial Bone Anchoring Device with Modular Sleeve Insert
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Solution Overview
Problem
Existing polyaxial bone anchoring devices with 360° pivot angles face challenges in ease of insertion and flexibility, particularly in areas with complex geometries or limited space, and lack modularity for combining different implant components.
Innovation Solution
A polyaxial bone anchoring device with a sleeve-like insert piece and pressure member that allows pre-assembly onto a bone anchoring element already implanted in the bone, enabling easy assembly and combination with various shanks and receiving parts, providing an enlarged pivot angle of at least 45° and 360° adjustability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If the receiving part is pre-assembled with pressure member and insert piece, then the assembly flexibility is improved, but the device complexity increases
Solution Approach 1:
The receiving part is divided into separate components (receiving part, pressure member, insert piece) that can be pre-assembled in different configurations. This segmentation allows the components to be prepared separately and then combined with the bone anchoring element in situ, providing assembly flexibility while managing complexity through modular design
Solution Approach 2:
The receiving part can be pre-assembled with the pressure member and insert piece before surgery. This preliminary preparation allows the components to be ready for immediate use, improving surgical efficiency and flexibility in different surgical scenarios without requiring complex intraoperative assembly procedures
2Ease of operation
If the bone anchoring element is inserted first, then the ease of insertion is improved, but the device complexity increases
Solution Approach 1:
The bone anchoring element can be inserted into the bone first, and then the receiving part with pre-assembled components is attached to the head of the anchoring element. This sequence simplifies the insertion process by avoiding the need to assemble all components before insertion, making the procedure easier to perform
Solution Approach 2:
The insert piece is positioned around the head of the bone anchoring element, creating a nested configuration where the insert piece surrounds the anchoring element head. This nested design allows the receiving part to be attached after insertion, providing ease of insertion while integrating multiple components in a compact arrangement
3Adaptability or versatility
If the pivot angle is enlarged to at least 45°, then the adaptability is improved, but the structural complexity increases
Solution Approach 1:
The insert piece and head interface are designed with spherical or curved surfaces that enable pivoting motion. This curved geometry naturally provides a range of motion including pivot angles of at least 45°, improving adaptability for different anatomical configurations without requiring complex mechanical joints or multiple articulation points
Solution Approach 2:
The connection between the bone anchoring element and the receiving part is designed to be dynamic rather than fixed. The insert piece allows the head to pivot relative to the shank body, providing adaptability for different surgical needs while maintaining a relatively simple structural design through controlled mobility
Data Source
AI summary
A polyaxial bone anchoring device includes a receiving part configured to be pivotably connected to a head of an anchoring element, the receiving part having a channel for receiving a rod and an accommodation space having an opening for accommodating the head, and a sleeve-like insert piece having a sleeve axis and a spherical segment-shaped outer surface portion. The insert piece is configured to be positioned around a portion of the head in the receiving part and to pivot in the receiving part, and includes a first part and a separable second part configured to be connected with the first part by a connection structure configured to permit translational movement between the first part and the second part in a direction transverse to the sleeve axis, while preventing movement between the first part and the second part in a direction parallel to the sleeve axis.