Snap-Lock Implant Screw Sleeve for Tulip Alignment
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Solution Overview
Problem
Existing polyaxial implant screws face challenges in aligning the tulip relative to the pedicle screw shaft during distraction and compression maneuvers, leading to potential thread failure and misalignment issues, which can result in reduced locking force or deformation of the tulip sections.
Innovation Solution
A mounting sleeve designed for polyaxial implant screws that can be quickly and easily attached via a snap or bayonet lock, featuring predefined contact areas for distraction and compression instruments to automatically align the tulip with the coupling rod, reducing tilting moments and ensuring secure fixation without thread damage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the tulip is manually aligned during distraction and compression maneuvers, then the alignment precision may be insufficient, but the operation time is reduced
Solution Approach 1:
The mounting sleeve is pre-equipped with defined contact areas that automatically guide the tulip into the correct alignment position when force is applied during distraction or compression maneuvers, eliminating the need for manual alignment adjustments and ensuring precise positioning from the start
Solution Approach 2:
The mounting sleeve acts as an intermediary device between the distraction/compression instrument and the tulip, transferring the applied force through its defined contact areas to achieve automatic alignment while protecting the tulip from direct mechanical stress
2Ease of operation
If the tulip is fixed without a mounting sleeve, then the surgical access is unobstructed, but the locking force may be reduced due to misalignment
Solution Approach 1:
The mounting sleeve serves as a temporary intermediary structure that maintains precise alignment between the tulip and coupling rod during critical operations, ensuring maximum locking force while being transparent to surgical access due to its minimalistic design
Solution Approach 2:
The mounting sleeve is a temporary device that is discarded after serving its alignment and protection function during distraction/compression maneuvers, allowing the final fixed structure to achieve full strength without the sleeve's interference
3Device complexity
If the tulip is aligned without a mounting sleeve, then the device complexity is reduced, but thread failure may occur due to tilting moments
Solution Approach 1:
The mounting sleeve acts as a protective intermediary that absorbs and distributes tilting moments and radial forces during alignment maneuvers, preventing these harmful forces from reaching the thread connection between the grub screw and tulip, thereby ensuring thread reliability
Solution Approach 2:
The mounting sleeve provides beforehand cushioning by absorbing potential misalignment forces and tilting moments before they can affect the thread connection, protecting the grub screw-tulip interface from damage during the alignment process
Data Source
Figure 1~3
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Figure 6~8
AI summary
Disclosed is a sleeve (2) for a body (6) of an implant screw (1), in particular for spinal surgery, and an implant screw (1) with a body/tulip (6) onto which the sleeve (2) can be placed and secured, for example, by a snap connection. The sleeve (2) serves as a defined attachment (16, 20) for a compression instrument or for a distraction instrument, or the sleeve (2) has at least one such attachment (16, 20). According to a first principle, four nose-shaped attachments (16) and further attachments (20) spaced apart along a central axis can be provided. Or, according to a second principle, the sleeve (2) has inclined, e.g., flattened regions (19), so that free spaces are created on the outer circumference of the sleeve (2), which allow the forceps (12) to approach the central axis (11) of the sleeve (2) and the body (6) in an inclined position.