Spinal Stabilization Sleeve Assembly Preventing Screw Detachment
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Solution Overview
Problem
Conventional minimally invasive spinal stabilization systems face challenges with the detachment of polyaxial screws from inner sleeves during surgery, requiring large incisions and using delicate, prone-to-breakage securing screws, which complicates the procedure and prolongs recovery time.
Innovation Solution
A novel inner and outer sleeve assembly that slides over the coupling between a polyaxial screw and an inner sleeve, featuring a longitudinal slot and register keys for proper orientation and alignment, preventing detachment and allowing easy manipulation with a handle, eliminating the need for separate screws and drivers.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional securing screws and drivers are used to attach the sleeve to the polyaxial screw, then the sleeve can be secured during surgery, but the screws are delicate and prone to breakage, requiring large incisions for retrieval and complicating the procedure
Solution Approach 1:
The patent removes the delicate securing screws and driver from the system entirely. Instead, the outer sleeve itself performs the securing function through its interference fit with the polyaxial screw, eliminating the need for separate fastening components that could break and require complex retrieval procedures.
Solution Approach 2:
The outer sleeve serves multiple functions: it provides structural support, maintains alignment of the inner sleeve and polyaxial screw, and acts as the securing mechanism itself through its interference fit. This multi-functionality eliminates the need for separate securing screws and drivers, simplifying the overall procedure.
2Reliability
If separate securing screws and drivers are used, then the sleeve can be attached to the polyaxial screw, but the procedure becomes cumbersome and time-consuming
Solution Approach 1:
The patent combines the securing function with the structural support function into a single component - the outer sleeve. By integrating these functions, the procedure is streamlined as surgeons no longer need to separately attach securing screws and manipulate drivers, reducing surgical time while maintaining reliable attachment.
3Reliability
If the sleeve design requires separate screws and drivers, then attachment is possible, but tissue trauma increases and recovery time extends due to cumbersome procedure
Solution Approach 1:
By removing the separate securing screws and drivers from the system, the procedure becomes less invasive. The outer sleeve's interference fit mechanism allows for secure attachment without requiring additional incisions or manipulations that would increase tissue trauma, thus reducing harmful effects on patient tissue while maintaining reliable attachment.
Data Source
AI summary
The present invention is a one or two-part sleeve assembly for use during minimally invasive spinal stabilization surgery. An outer sleeve is designed to slide over the coupling between a polyaxial screw and an inner sleeve so as to prevent the screw from becoming disengaged from the inner sleeve during surgery. The outer sleeve includes a lower generally cylindrical wall having a slot, and an upper extension having an outwardly protruding manipulation handle attached to it. The slot in the lower section extends the entire length of the cylindrical wall, giving it a generally “C” shaped cross section. This slot corresponds with a similar slot on the inner sleeve for receiving a stabilizing rod to be attached to the polyaxial screw during surgery. The interior diameter of the lower section is approximately the same as the outer diameter of the inner sleeve, so that the outer sleeve may slide snugly over the inner sleeve and the screw coupling. In addition, the edges of the cylindrical wall adjacent to the longitudinal slot are flattened so as to conform to the shape of the inner sleeve and the head portion of the polyaxial screw where it couples with the inner sleeve.