ENT Shaver Cutting Assembly With Clog-Reducing Tip
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Solution Overview
Problem
Clogging of ENT shaver devices during endoscopic sinus surgery due to trapping of sinus bone and tissue at the distal tip or within the tubes, which impedes effective material removal.
Innovation Solution
A surgical instrument with a clog-reducing tip featuring a cutting assembly that includes a rotatable inner tube with a projection within its lumen, reducing the cross-sectional area and guiding material through the cutting window to minimize clogging by ensuring it is sufficiently small before entering the lumen, combined with a drive assembly that facilitates rotation and aspiration.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a conventional ENT shaver device is used with a standard tube structure, then the device can perform basic cutting functions, but clogging occurs due to trapping of sinus bone and tissue at the distal tip or within the tubes
Solution Approach 1:
The tube structure is segmented into multiple regions with different cross-sectional areas. The lumen includes a first region with a first cross-sectional area and a second region with a second cross-sectional area that is smaller than the first. This segmentation allows material to be progressively constrained and reduced in size as it passes through the tube, preventing clogging while maintaining a relatively simple overall tube structure.
Solution Approach 2:
Different regions of the tube lumen have different local qualities in terms of cross-sectional area. The first region has a larger cross-sectional area to receive cut material, while the second region has a smaller cross-sectional area to reduce material size and prevent clogging. This local variation in geometry optimizes the tube's performance for its specific function of material transport without requiring complete structural redesign.
2Reliability
If the lumen cross-sectional area is reduced to prevent clogging, then material size is controlled, but the device complexity increases due to additional structural features
Solution Approach 1:
The tube assembly is configured to be rotatable relative to the outer tube, creating a dynamic interaction between the inner and outer tube surfaces. This rotation allows the cut material to be progressively reduced in size as it passes through the lumen, enhancing the material size control function without requiring complex internal structures or additional components within the lumen itself.
Solution Approach 2:
The cutting function and material transport function are merged into a single integrated tube assembly. The inner tube with the varied cross-sectional lumen serves both as a structural component and as the material transport pathway. The interaction between the rotatable inner tube and outer tube combines cutting action with material size reduction and transport, eliminating the need for separate cutting mechanisms and transport channels.
3Ease of manufacture
If a simple tube structure is used, then the device is easier to manufacture, but clogging occurs due to inadequate material size reduction
Solution Approach 1:
The tube lumen is designed with a predetermined variation in cross-sectional area, creating a gradual transition from a larger first region to a smaller second region. This preliminary geometric configuration is built into the tube structure during manufacturing, enabling automatic material size reduction and clog prevention without requiring complex active control mechanisms or post-manufacturing adjustments. The structure itself performs the material conditioning function.
Data Source
AI summary
A cutting assembly configured to be removably coupled to a drive assembly of a surgical instrument. An inner tube is coaxially and rotatably disposed within an outer tube and defines a lumen in communication with a cutting window. A projection is disposed within the inner tube. At least a portion of the projection is positioned distal to a proximal boundary of the cutting window. The projection may define a throat having a distance between the proximal boundary of the cutting window on the outer tube and a nearest point on the projection. The throat may be narrower than a diameter of the lumen. An inner surface of the projection permits cutting action to continue until the material is sufficiently reduced to pass through the throat. The projection may be formed by an insert bonded within the inner tube.