Bone Cutting Instrument with Expandable Blades
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Solution Overview
Problem
Conventional surgical instruments for bone cutting and tunneling have large exterior projections and gaps that can lead to clogging with bone fragments and debris, limiting their effectiveness in creating sockets and tunnels for various orthopedic procedures.
Innovation Solution
A surgical bone cutting instrument with radially expandable cutting blades housed in a hollow shaft, featuring a piercing tip and an activation rod that rotates to expand the blades outwardly through apertures in the shaft, allowing for efficient cutting and tunnel formation with reduced risk of debris accumulation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If conventional cutting instruments have large exterior projections and gaps for blade deployment, then cutting functionality is achieved, but bone fragments and debris become lodged in these areas interfering with operation
Solution Approach 1:
The cutting blades are nested within the hollow shaft in a retracted position, similar to a nested doll structure. The blades can be deployed outward through apertures in the shaft wall when needed, but otherwise remain contained within the shaft, eliminating large exterior projections that would catch debris.
Solution Approach 2:
The cutting blades are made dynamically deployable rather than statically fixed. An activation mechanism allows the blades to transition between a retracted state (smooth exterior surface) and a deployed state (cutting functionality), enabling the instrument to adapt its configuration based on operational needs.
2Adaptability or versatility
If cutting blades are deployed through large openings in the shaft, then bone cutting capability is enabled, but the large openings cause bone fragments to become clogged
Solution Approach 1:
Instead of having large continuous openings, the shaft has multiple small discrete apertures distributed along its length. Each aperture is just large enough to allow the cutting blade to pass through, minimizing the opening size while maintaining cutting functionality. This local optimization reduces debris accumulation compared to large continuous openings.
Solution Approach 2:
The cutting blade deployment mechanism is segmented into multiple discrete apertures rather than one large opening. The activation mechanism can selectively deploy blades through individual apertures, allowing controlled deployment while maintaining a mostly closed shaft structure that prevents debris entry.
3Reliability
If the instrument has a smooth exterior surface without large projections, then debris accumulation is minimized, but the ability to deploy cutting blades is compromised
Solution Approach 1:
The instrument maintains a dynamically changeable exterior surface. The apertures remain closed and the surface stays smooth during insertion and advancement to prevent debris accumulation. When cutting is required, the activation mechanism opens the apertures and deploys the blades, temporarily transforming the surface geometry to enable cutting functionality.
Solution Approach 2:
The cutting blades are pre-positioned within the shaft in a retracted state before deployment is needed. This preliminary positioning allows the shaft to maintain its smooth exterior surface during insertion and tunnel formation, and the blades are only deployed when the instrument reaches the target location and cutting is required.
Data Source
AI summary
An instrument for cutting bone includes a hollow shaft having a sidewall. A cutting element is at least partially housed in the hollow shaft. The cutting element can include one or more cutting blades that are radially expandable through the sidewall. The instrument can also include a piercing tip on a distal end of the hollow shaft is located distally of the one or more cutting blades. In addition, the instrument can include an expansion element for radially expanding the one or more cutting blades through the sidewall.