Robotic Surgical Saw Control to Prevent Bone Cutting Skiving
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Solution Overview
Problem
Conventional surgical saws experience undesirable skiving during initial cuts on non-flat hard tissue surfaces, such as the ends of a femur, leading to inaccuracies and increased cutting times, especially when using cutting guides or robotic systems.
Innovation Solution
A robotic cutting system with a manipulator, robotic arm, and control system that autonomously aligns and moves a saw tool along a defined cutting plane, constrained by virtual boundaries to prevent skiving, using haptic feedback and navigation systems for precise bone cuts.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If a cutting guide is used to hold the saw blade in place, then skiving is reduced, but the cutting time increases due to the need to secure the guide to the bone
Solution Approach 1:
The patent removes the cutting guide from the system entirely, replacing it with a robotic arm that autonomously positions and moves the saw blade along the cutting plane. This extraction eliminates the time-consuming step of securing a cutting guide to the bone while maintaining cutting accuracy through robotic control
Solution Approach 2:
The robotic system performs self-positioning and self-guiding functions that previously required external cutting guides. The robotic arm autonomously aligns itself with the cutting plane and maintains precise positioning throughout the cutting process without requiring separate guiding apparatus to be attached to the bone
2Manufacturing precision
If cutting guides are used, then blade positioning is improved, but longer blades are required which still introduce skiving effects
Solution Approach 1:
The patent eliminates cutting guides entirely and replaces them with a robotic positioning system. This removes the need for longer blades that were required when using cutting guides, thereby eliminating the skiving effects associated with extended blade lengths while maintaining precise blade positioning through robotic control
Solution Approach 2:
The patent replaces the mechanical cutting guide system with a robotic control system. The robotic arm uses sensors, actuators, and control algorithms to position and guide the blade, substituting mechanical guidance with an automated control system that achieves superior positioning accuracy without the drawbacks of physical guides
3Ease of operation
If conventional surgical saws are used on non-flat bone surfaces, then basic cutting function is maintained, but skiving occurs leading to deviation from intended cut plane
Solution Approach 1:
The robotic system dynamically adjusts the blade position and orientation in real-time to accommodate non-flat bone surfaces. The robotic arm can move in multiple degrees of freedom, allowing it to adapt to the complex geometry of bone surfaces while maintaining precise alignment with the intended cutting plane throughout the cutting process
Solution Approach 2:
The robotic system incorporates sensors that provide real-time feedback on blade position, bone surface geometry, and cutting progress. This feedback loop allows the control system to make continuous adjustments to maintain accurate cutting plane alignment, preventing skiving even on irregular bone surfaces
Data Source
AI summary
A surgical system and method of operating the same include a manipulator with a base, a robotic arm coupled to the base, and a saw tool coupled to the robotic arm to perform a cut of a bone. A control system is coupled the manipulator and obtains data defining a cutting plane for the bone and a pre-determined depth of the bone to be cut by the saw tool along the cutting plane. The control system associates a virtual planar boundary with the bone along the cutting plane and controls the manipulator to autonomously align the saw tool to the cutting plane. The control system controls the manipulator to activate and autonomously move the saw tool along the cutting plane to perform the cut. Autonomous movement of the saw tool is constrained to remain within the virtual planar boundary and not exceed the pre-determined depth.