Intervertebral Spacer Locking Member for Screw Backout Prevention
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing intervertebral spacers face issues with bone screws loosening and backing out over time, necessitating improved stabilization mechanisms.
Innovation Solution
The intervertebral spacer assembly features a locking member with anti-backout members and a rotatable locking mechanism, including a collet and annular ridge, to securely fasten bone screws in place, preventing them from backing out.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If bone screws are used to stabilize the intervertebral spacer during fusion, then stabilization is improved, but the screws may become loose and back out over time
Solution Approach 1:
The locking member is pre-configured with engagement features (recesses and protrusions) that automatically engage with the bone screws upon insertion. This preliminary configuration ensures that when the locking member rotates to the locked position, the anti-backout members are already positioned to prevent screw backout, eliminating the need for separate locking steps and ensuring immediate retention.
Solution Approach 2:
The locking member acts as an intermediary component between the intervertebral spacer and the bone screws. It provides a mechanical interface that translates rotational motion into linear locking action, mediating the connection between the spacer body and the screws while preventing direct backout through its anti-backout members.
2Reliability
If a locking mechanism is added to prevent screw backout, then screw retention is improved, but device complexity increases
Solution Approach 1:
The locking member combines multiple functions into a single component: it provides the locking interface for bone screws, incorporates anti-backout members to prevent screw loosening, and integrates with the intervertebral spacer body through the collet mechanism. This merging reduces the need for separate locking components and simplifies the overall assembly.
Solution Approach 2:
The locking mechanism is designed to be self-locking through the interaction between the stop protrusions and recesses. Once the locking member rotates to the locked position, the anti-backout members automatically engage with the bone screws without requiring additional actuators, springs, or complex locking mechanisms. The system serves itself by using the rotational motion to automatically engage the retention features.
3Stability of the object's composition
If multiple fastener channels are used to secure the spacer, then fixation stability is improved, but the risk of fastener backout increases
Solution Approach 1:
The locking member divides the retention function into multiple anti-backout members, each associated with specific fastener channels. This segmentation allows each bone screw to be independently secured by its corresponding anti-backout member, providing targeted retention for each fastener while maintaining overall system stability through the collective action of all locking features.
Data Source
Figure 1A~1B
Figure 1C~1D
Figure 1E~1F
AI summary
An intervertebral spacer may include a fastener channel configured to receive a fastener, a locking member channel, and a locking member. The locking member channel may include an inner wall and one or more inner wall engagement features. The locking member may include an anti-backout member, a collet retainable within the locking member channel, and one or more collet engagement features. The locking member may be rotatable within the locking member channel between an unlocked position and a locked position. The one or more collet engagement features may engage the one or more inner wall engagement features in order to retain the locking member in either the unlocked position or the locked position, such that the anti-backout member may selectively obstruct the fastener channel and prevent the fastener from backing out of the fastener channel.