Computer Controlled Surgical Rotary Tool for Bone Resection
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Solution Overview
Problem
Current robotic surgical systems for bone resection in total knee replacement are inefficient, requiring lengthy procedures and introducing errors due to the use of burrs, cutting guides, and traditional saws.
Innovation Solution
A computer-controlled surgical rotary tool with a tracking array, powered rotary cutting tip, and linear actuators, which maintains the cutting tip on a virtual cutting plane defined by a computer-assisted surgical system, ensuring precise bone resection.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a robotic arm with cutting guides and traditional saws is used for bone resection, then the surgical procedure can be performed with conventional tools, but the resection time is lengthy and multiple error sources are introduced
Solution Approach 1:
The patent combines the cutting guide and saw into a single integrated robotic end effector assembly. The cutting guide is built into the robotic arm structure, and the saw is directly mounted to it, eliminating the need for separate burring and guiding steps. This integration allows the robotic system to perform both guidance and cutting functions simultaneously, reducing resection time while maintaining precision through computer control.
Solution Approach 2:
The patent replaces traditional mechanical cutting guides and saws with a computer-controlled robotic system. Instead of relying on physical jigs and manual saw operation, the system uses computerized positioning and control to guide the cutting tool along predetermined paths, eliminating errors associated with manual guide placement and saw alignment while reducing overall procedure time.
2Productivity
If burrs are used for volumetric resection, then bone can be removed, but the resection rate is slow and the procedure takes excessive time
Solution Approach 1:
The patent employs a reciprocating saw mechanism that oscillates back and forth during cutting. This dynamic cutting action allows for faster material removal compared to static burring. The reciprocating motion enables the saw to efficiently cut through bone at a controlled rate, significantly increasing the resection rate while maintaining precision through robotic positioning.
Solution Approach 2:
The patent changes the cutting method from burring (grinding) to sawing (reciprocating cutting). This parameter change in the cutting mechanism fundamentally increases the resection rate. The saw blade removes bone more efficiently than burrs by shearing rather than grinding, reducing procedure duration while the robotic control maintains accuracy.
3Manufacturing precision
If cutting guides are placed using burred post holes, then bone resection can be guided, but additional errors are introduced and the process becomes more complex
Solution Approach 1:
The patent extracts the cutting guide function from separate physical jigs and integrates it directly into the robotic arm structure. Instead of placing external cutting guides on the bone, the guide is built into the robotic end effector, eliminating the need for post hole burring and guide placement steps. This reduces complexity by removing intermediate components and steps while improving precision through direct robotic control.
Solution Approach 2:
The robotic end effector assembly serves multiple functions: it provides structural support, contains the cutting guide, mounts the saw, and enables computer-controlled positioning. This multi-functional design eliminates the need for separate cutting guides and simplifies the overall system by combining what were previously separate components into a single integrated unit.
4Measurement precision
If a robotic arm directly constrains the saw to a resection plane, then cutting accuracy is improved, but the system complexity and cost greatly increase
Solution Approach 1:
The patent introduces a computer control system as an intermediary between the robotic arm and the cutting process. Rather than relying solely on complex mechanical constraints, the computer system calculates and guides the robotic arm's movements to maintain the saw on the resection plane. This software-based mediation achieves high precision while reducing mechanical complexity compared to purely hardware-based constraint systems.
Data Source
AI summary
A rotary tool includes a tool body and a powered rotary cutting tooltip that is oriented and positioned relative to the tool body by a plurality of processor-controlled actuators that provide degrees of freedom. The processor uses a surgical tracking system to identify the pose of the tool body and the tooltip relative to a patient's anatomy and controls the actuators to maintain the tooltip within a predetermined cutting plan to compensate for deviation of a surgeon's hand or a robotic arm controlling the tool body during a cutting operation.