Pedicle Screw Locking Sleeve with Segmented Flank Positioning
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Solution Overview
Problem
Existing securing sleeves for pedicle screws with extended flanks lack defined positioning and stability, leading to potential premature breakage and tissue damage during minimally invasive spinal surgery, and are difficult to clean due to complex structures.
Innovation Solution
A locking sleeve with sliding blocks and a stop ring that securely positions the flanks without narrowing the instrument-accessible passage, featuring conical sliding blocks for maximum separation and an alignment groove for correction rod insertion, reducing tissue damage and facilitating alignment of multiple screws.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If a simple ring flank protection sleeve with smooth inner peripheral surface is used, then the structure is simple and easy to manufacture, but the flanks can move uncontrollably along the smooth surface and the position is not firmly defined
Solution Approach 1:
The securing sleeve has a smooth inner peripheral surface in the axial direction for easy manufacture, but includes transverse protrusions that create localized rough surfaces. These localized rough areas firmly engage with the flanks to prevent unwanted movement, while the overall simple structure remains easy to manufacture.
2Manufacturing precision
If receiving openings completely enclose the flanks to define position, then the flanks are securely positioned, but the instrument-accessible passage between the flanks narrows making positioning difficult
Solution Approach 1:
Instead of using a single continuous receiving opening that completely encloses the flanks, the invention uses multiple discrete transverse protrusions spaced along the axial direction. These segmented engagement points securely position the flanks while leaving the space between them open, maintaining an instrument-accessible passage for surgeon positioning.
3Manufacturing precision
If the securing sleeve structure is complex with multiple engagement features, then the flanks are firmly positioned, but the sleeve becomes difficult to clean due to undercuts and blind spots
Solution Approach 1:
Instead of creating complex internal structures with undercuts and blind spots to achieve firm positioning, the invention uses simple transverse protrusions that extend from the inner peripheral surface. This inverted approach achieves secure flank engagement while maintaining a simple, cleanable structure without hard-to-reach areas.
4Ease of operation
If the correction rod is inserted close to the patient's tissue for alignment, then the alignment function is achieved, but the tissue can be unnecessarily damaged by deformation of the correction rod
Solution Approach 1:
The securing sleeve acts as an intermediary structure that provides alignment features (such as transverse alignment grooves or protrusions) spaced away from the patient's tissue. The correction rod engages with these intermediary alignment features on the sleeve rather than requiring direct insertion close to the tissue, reducing the risk of tissue damage from rod deformation.
Data Source
Figure 1
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Figure 4~5
AI summary
A locking sleeve (1) for receiving and securing the flanks (8) of a pedicle screw, with a stop ring (7) on the inside of the locking sleeve, which rests on the upper edge of the flanks and limits the receiving depth of the flanks into the locking sleeve, and a plurality of T-nuts (2) on the inside of the locking sleeve, which can be inserted between the flanks of the pedicle screw to define a fixed distance between the flanks.