Reciprocating Rasping System for Surgical Precision
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Solution Overview
Problem
Current surgical instruments with rotational cutting surfaces, such as shavers and burrs, lack precision and control when removing osteophytes or chondrocytes, especially in confined spaces, due to moment forces that pull the cutting end off track, and can damage adjacent soft tissues.
Innovation Solution
A reciprocating rasping system with a flat cutting surface and suction capability, converting rotational motion into axial reciprocation for improved control and efficient debris removal, featuring a rasp head with uni-directional teeth oriented towards a suction opening to facilitate precise tissue removal and minimize soft tissue injury.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If rotational cutting surfaces (shavers and burrs) are used to remove hard tissues, then cutting efficiency is improved, but control precision and ability to create flat surfaces deteriorate due to moment forces pulling the cutting end off track
Solution Approach 1:
The patent inverts the conventional rotational cutting approach by using a reciprocating linear motion instead. The rasp head moves back and forth in a linear reciprocating motion driven by a cam mechanism, eliminating the moment forces that cause rotational tools to pull off track. This inversion of the cutting motion paradigm enables precise flat surface preparation while maintaining effective tissue removal.
Solution Approach 2:
The patent employs dynamic motion conversion through a cam mechanism that transforms continuous rotational handpiece motion into reciprocating linear motion of the rasp head. This dynamic transformation allows the cutting element to oscillate rapidly back and forth along a controlled linear path, providing both efficiency and precision in tissue removal and surface preparation.
2Productivity
If rotational cutting surfaces are used in confined spaces, then cutting capability is maintained, but ease of operation and control deteriorate as adjacent soft tissues are easily grabbed by rotating cutting surfaces
Solution Approach 1:
By inverting from rotational to reciprocating linear motion, the cutting tool presents a non-rotating profile that does not grab soft tissues. The linear back-and-forth motion of the rasp head allows the surgeon to precisely control the cutting action in confined spaces without the dangerous grabbing effect of rotating surfaces, significantly improving safety and ease of operation.
Solution Approach 2:
The rasp head is designed with a compact structure featuring segmented cutting teeth arranged on a flat surface. This segmentation allows the cutting function to be concentrated in a small, controlled area that can be precisely positioned in confined joint spaces, improving both control and safety compared to larger rotating instruments.
3Manufacturing precision
If a flat cutting surface is used to improve control and surface preparation, then manufacturing precision is improved, but device complexity increases due to motion conversion mechanism
Solution Approach 1:
The cam mechanism provides an elegant dynamic solution for motion conversion. The cam profile is designed to convert the simple rotational motion of the handpiece into the desired reciprocating linear motion of the rasp head. This dynamic approach achieves precise flat surface preparation without requiring complex multi-component mechanisms, maintaining relative simplicity while delivering superior control and precision.
Data Source
AI summary
A surgical rasping system functional in multiple orthopedic applications, including but not limited to shoulder, knee, hip, wrist, ankle, spinal, or other joint procedures. The system comprises a rasping head which may be low profile and offer a flat cutting/rasping surface, and is configured to be driven by an attached hub that translates a rotational movement into a reciprocating motion. Suction for removal of bone fragments or other tissues is provided through an opening spaced apart from or adjacent to the rasping surface.