Spinal Implant Flexible Screw Lock for Easy Inserter Removal
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Solution Overview
Problem
Existing spinal implants face challenges with threaded connections that can lead to inserters sticking in situ, making removal difficult, and require additional steps or components for locking mechanisms, which complicate the surgical procedure.
Innovation Solution
A spinal implant with a 3D printed, passive locking mechanism featuring deflectable latches and integrated threads provides tactile feedback for secure screw insertion and retention, while inserters use a barrel-cam mechanism for efficient attachment and removal without threads, and drivers employ cam surfaces or flexible tabs for easy screw engagement and detachment.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If threaded connections are used for bone screw fixation, then secure retention is achieved, but inserters may stick in situ making removal difficult
Solution Approach 1:
The fixation aperture is divided into distinct functional zones: a threaded distal portion for secure screw retention and a smooth proximal portion for easy inserter passage. This segmentation allows the inserter to pass through the aperture without threading engagement, then disengage at the transition zone, enabling simple removal while maintaining reliable screw fixation.
Solution Approach 2:
A transition zone acts as an intermediary between the threaded fixation portion and the smooth passage portion. This intermediate region allows the inserter to smoothly transition from engaged to disengaged state, facilitating easy removal while preserving the threaded connection's retention capability for the bone screw.
2Reliability
If additional locking mechanisms are added to prevent screw backout, then retention reliability improves, but device complexity increases
Solution Approach 1:
The anti-backout retention function is merged with the existing threaded aperture structure. The threads themselves provide both fixation and prevention of backout, eliminating the need for separate locking mechanisms. The solid wall containing the threads integrates multiple functions into a single structural element.
Solution Approach 2:
The threaded aperture structure is self-sufficient, providing both initial screw capture and prevention of backout through the same threaded engagement. The structure serves multiple retention functions without requiring additional active components or complex locking mechanisms.
3Reliability
If multiple components are used for locking mechanisms, then retention is improved, but surgical procedure time increases
Solution Approach 1:
The complex multi-component locking mechanisms are extracted and replaced with a simplified single-piece solid wall containing integrated threads. This extraction of unnecessary complexity reduces the number of components that need to be assembled and manipulated during surgery, thereby reducing procedure time while maintaining retention reliability.
4Strength
If threaded connections are used for implant attachment, then secure fixation is achieved, but removal becomes difficult requiring additional devices
Solution Approach 1:
The aperture structure is segmented into a threaded distal portion for strong screw fixation and a smooth proximal portion for easy inserter/drive passage. This allows the implant to be securely attached through threaded engagement while enabling simple removal by passing the drive through the smooth portion and disengaging at the transition zone.
Data Source
AI summary
The present disclosure includes bone screws, spinal implant, drivers, and their assemblies thereof for surgical procedures of the spine including but not limited to anterior lumbar interbody fusion (ALIF) procedures.