Curved Cutting Teeth Rotary Surgical Instruments
Solution Overview
Problem
Conventional rotary surgical instruments with cutting teeth require high torque and force, experience non-uniform shearing action, and are prone to trauma and misalignment due to fragile tips and inadequate strength, leading to inefficiencies in cutting anatomical tissue.
Innovation Solution
The design features elongate tubular members with cutting teeth that have convex sides and staggered tips, formed by laser cutting to create a knife-sharp edge along the entire length, allowing for uniform and continuous shear cutting action with reduced trauma and increased rigidity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If cutting teeth are made with traditional designs, then they can cut anatomical tissue, but they require high torque and force and experience non-uniform shearing action
Solution Approach 1:
The cutting teeth are designed with convexly curved sides instead of flat or concave surfaces. This curvature allows the teeth to engage with anatomical tissue more effectively, distributing the cutting load uniformly across the tooth surface and reducing the peak torque and force requirements while maintaining continuous shearing action throughout the rotation cycle.
Solution Approach 2:
The geometric parameters of the cutting teeth are optimized by forming convex sides with specific curvature radii and angles. This parameter optimization ensures uniform engagement with tissue, creating consistent shearing forces throughout the rotation cycle and eliminating the non-uniform loading patterns of traditional designs.
2Reliability
If cutting teeth have traditional geometries, then they can perform cutting function, but they are prone to trauma and misalignment due to fragile tips and inadequate strength
Solution Approach 1:
The convex curvature of the cutting teeth provides both strength and sharpness. The curved geometry distributes stress uniformly across the tooth structure, eliminating fragile tips while maintaining the ability to cut tissue effectively. This curvature also ensures consistent engagement with tissue, preventing misalignment during operation.
Solution Approach 2:
The cutting teeth are formed through laser cutting of tubular members, creating a composite structure with optimized wall thickness and geometric profile. This manufacturing process produces teeth that combine the strength needed for reliable operation with the sharp edges required for effective cutting, reducing both trauma and misalignment.
3Force
If conventional cutting elements are used, then cutting can be performed, but they cause non-uniform shearing action and require high force
Solution Approach 1:
The convexly curved cutting teeth maintain continuous contact with anatomical tissue throughout the rotation cycle, ensuring uniform shearing action from start to finish. This continuous engagement eliminates the intermittent loading patterns of traditional designs, providing consistent cutting force and improved productivity.
Solution Approach 2:
The convex curvature ensures that the cutting teeth engage with tissue in a uniform manner throughout rotation, creating consistent shearing forces. This geometric design distributes the cutting action evenly over time and space, eliminating non-uniform loading while reducing the peak force requirements.
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
This design enhances cutting effectiveness by distributing torque uniformly, reducing the need for high force and minimizing tissue trauma, while maintaining alignment and reducing the size of the incision required.
Implementation Method 1
The cutting teeth are formed in the inner member by normal laser cutting, resulting in formation of a knife-sharp cutting edge
Data Source
AI summary
A rotary surgical instrument includes an outer member having an aperture in a distal portion thereof, and an inner member for being rotatably disposed within the outer member to move a cutting element on the inner member past the aperture to cut anatomical tissue. The inner member has an aperture, and the cutting element comprises first and second rows of cutting teeth extending longitudinally along opposite sides of the inner member aperture. Each cutting tooth is convexly curved, the cutting teeth of one row curving in opposition to the cutting teeth of the other row. The rows of cutting teeth have their tips staggered.