Multi-Axial Screw Assembly Rotatable Base Member Angulation
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing bone fixation devices, such as screws and hooks, often require precise placement and limited angulation, which can complicate the correction of vertebral malformations or injuries, as they provide a fixed maximum angle between the fastening and receiving portions, restricting versatility and ease of use.
Innovation Solution
A multi-axial screw assembly comprising a receiver, base member, and crown, where the base member is rotatable relative to the receiver, allowing for greater angulation and versatility through the use of a channel for a rod and an aperture system that accommodates a bone anchoring member, enabling the base member to be positioned for optimal alignment and angulation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If a fixed maximum angle is provided between fastening and receiving portions, then device stability is improved, but directional versatility deteriorates
Solution Approach 1:
The base member is made rotatable relative to the receiver through a bearing mechanism, transforming the fixed angular relationship into a dynamic, adjustable one. This allows the base member to be rotated to different angular positions (e.g., 0°, 45°, 90°) while maintaining stability at each positioned, thereby resolving the contradiction between stability and directional versatility
Solution Approach 2:
The device is divided into separable components (receiver, base member, crown) with independent rotational degrees of freedom. The base member can be rotated relative to the receiver, and the crown can be rotated relative to the base member, creating multiple segments that can be independently positioned to achieve both stability and versatility
2Reliability
If precise placement is required for bone fixation, then fixation reliability is improved, but ease of operation deteriorates
Solution Approach 1:
The rotatable base member and crown allow the surgeon to adjust the orientation and angulation of the fixation device after initial placement in the bone. This dynamic adjustment capability maintains fixation reliability while significantly improving ease of operation, as precise positioning can be achieved through rotation rather than requiring extremely precise initial placement
Data Source
Figure 1
Figure 2
Figure 3
AI summary
A multi-axial screw assembly comprises a receiver, a base member, and a crown. The receiver comprises a channel for receiving a rod and an aperture extending from a bottom portion of the receiver. The base member comprises an aperture extending through the base member and an opening on a bottom portion of the base member. The base member is configured to couple to the receiver such that the aperture of the receiver is generally aligned with the aperture of the base member. The base member is rotatable relative to the receiver. The crown is received in the receiver and configured to mate to the base member. The crown has a mating feature configured to couple to the base member such that the crown rotates the base member when the crown is rotated.