Pedicle Screw Retractor Blade Cam Lock Against Premature Opening
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Solution Overview
Problem
Existing surgical retractors face challenges in maintaining a clear surgical field by preventing premature opening of blades due to forces generated during screw manipulation, such as distracting or compressing, which can compromise the stability and effectiveness of tissue retraction.
Innovation Solution
A retractor system with actuating members featuring arced slots and cam mechanisms that allow blades to fixedly couple and decouple from pedicle screws using button-based actuation, minimizing resistance to opening or spreading forces through strategic alignment of arcs relative to pivot points, and incorporating resilient members or rod-driven actuation for controlled blade movement.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If traditional retractors are used to maintain surgical field stability, then tissue retraction is maintained, but resistance to blade opening increases during screw manipulation
Solution Approach 1:
The retractor blade incorporates a cam mechanism with an arced slot that allows the blade to dynamically adjust its coupling state with the pedicle screw. The cam mechanism enables the blade to transition between a locked position (during screw manipulation) and an unlocked position (for tissue retraction), optimizing both stability and ease of operation at different surgical stages
Solution Approach 2:
The arced slot geometry is specifically designed to change the mechanical parameters of the blade-screw interface. As the cam rotates within the arced slot, it alters the positional parameters and force transmission characteristics, reducing resistance to blade opening while maintaining surgical field stability through strategic alignment of the arc relative to the pivot point
2Reliability
If blades are firmly coupled to prevent premature opening, then surgical field stability improves, but ease of blade decoupling deteriorates
Solution Approach 1:
The cam mechanism provides dynamic control over blade coupling strength. During screw manipulation, the cam engages the arced slot to provide firm coupling and stability. When decoupling is needed, the cam can be actuated to disengage from the slot, allowing easy blade removal without compromising previous stability
Solution Approach 2:
The arced slot is pre-configured with specific geometric parameters that prepare the cam mechanism for both locking and unlocking functions. The arc's strategic alignment with the pivot point is established in advance, enabling the blade to automatically assume the correct position and coupling strength based on cam rotation, facilitating easy decoupling when required
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The system effectively maintains a stable surgical field by reducing resistance to blade actuation, ensuring consistent tissue retraction and preventing premature opening, thereby enhancing surgical precision and efficiency.
Implementation Method 1
The blade includes a cam. The cam includes a first cam plate including a first cam slot, a second cam plate including a second cam slot, and a pin included within the first and second cam slots
Implementation Method 2
The blade includes a resilient member coupled to the button
Data Source
AI summary
An embodiment of a retractor system includes a retractor blade with actuating members at the blade tip, which allow the blade to fixedly couple to and decouple from the shank of a pedicle screw with the press of a button. The actuating members each have an arced slot that acts like a cam when the button is depressed. The button-based actuation is based, at least in part, on the shape of the arcs relative to the pivot point. When the blade is in the relaxed state with the button not depressed the slope of the arc aligns with the pivot point. This prevents the actuating members from being opened from forces that may be generated during ordinary screw manipulation. When the blade is in the actuated state with the button depressed the slope of the arc is offset from the pivot point. This allows the blades to move as needed.