Nested Sleeve Surgical Screw Implantation Device
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Solution Overview
Problem
Current devices for implanting polyaxial screws in minimally invasive spinal surgery suffer from instability during use, leading to accidental decoupling under bending stresses and increased invasiveness, which can result in patient injury and procedural failures.
Innovation Solution
A device comprising an outer and inner sleeve with specific channel configurations and engagement mechanisms that securely couple and align with polyaxial screws, providing stability against bending, torsion, and traction stresses, while allowing for quick and easy use.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional devices are used for implanting polyaxial screws, then the procedure can be performed, but the devices are prone to accidental decoupling under bending stresses and cause increased invasiveness
Solution Approach 1:
The device employs a nested structure where an inner sleeve is positioned within an outer sleeve. The inner sleeve contains engagement elements that couple with the polyaxial screw, while the outer sleeve provides additional support and alignment. This nested configuration distributes mechanical stresses across multiple structural levels, preventing accidental decoupling under bending loads while maintaining a compact profile that reduces surgical invasiveness.
Solution Approach 2:
The device is divided into distinct functional segments: the outer sleeve with alignment features, the inner sleeve with engagement elements, and the polyaxial screw itself. This segmentation allows each component to perform its specific function optimally - the outer sleeve provides structural support and alignment, the inner sleeve ensures secure coupling, and the screw provides fixation - while collectively reducing the overall invasiveness compared to a monolithic device design.
2Reliability
If engagement mechanisms are added to prevent decoupling, then reliability improves, but device complexity increases
Solution Approach 1:
The device merges multiple functions into integrated components. The outer sleeve combines alignment features with structural support functions. The inner sleeve integrates engagement elements that simultaneously provide coupling security and stress distribution. The polyaxial screw head incorporates recesses that work with the engagement elements. This merging reduces the number of separate parts while maintaining high reliability against bending stresses.
Solution Approach 2:
The engagement mechanisms are designed with multi-functionality. The engagement elements on the inner sleeve not only prevent decoupling under bending stresses but also facilitate easy insertion and removal of the screw. The nested sleeve structure itself serves multiple purposes: providing structural support, enabling alignment, distributing stresses, and allowing for minimally invasive insertion. This multi-functionality reduces overall device complexity compared to having separate dedicated components for each function.
Data Source
AI summary
A device may include an outer sleeve with a hollow interior, and an inner sleeve with a hollow interior to couple axially and slidingly. The outer sleeve may include an outer central body, an outer proximal end part and an outer distal end part integrally connected to one another, and an outer channel extending along the entire outer proximal end part and along a substantial portion of the outer central body. The inner sleeve may include an inner central body, an inner proximal end part and an inner distal end part integrally connected to one another, and an inner channel extending along the entire inner proximal end part and along a substantial part of the inner central body. The inner sleeve may include, in the inner proximal end of the inner sleeve, a lateral engagement element, and an axial engagement element for releasably engaging a surgical screw.