Surgical Robot Passive End Effector for Precise Bone Cutting
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Solution Overview
Problem
During orthopedic surgeries, such as total knee arthroplasty, the precision of bone cuts is compromised due to limited visibility, difficulty in controlling oscillating surgical saws, and vibrations, which can result in inaccurate cuts and debris generation from saw blade contact with jigs.
Innovation Solution
A passive end effector system for a surgical robot that includes mechanisms to constrain the movement of a surgical saw within a working plane, ensuring precise alignment and reducing vibrations, combined with a tracking system to determine the pose of anatomical structures and the saw blade, allowing for accurate cutting plane alignment.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If a jig is used to guide the surgical saw, then the alignment of the cutting plane can be improved, but contact between the saw blade and the jig generates debris that risks entering the patient
Solution Approach 1:
The patent removes the traditional jig from the cutting process entirely. Instead of using a jig that contacts the bone and generates debris, the system uses a robotic arm to directly position and guide the oscillating surgical saw along the pre-planned cutting path, eliminating the source of debris generation while maintaining precise alignment through robotic control and pre-operative planning
Solution Approach 2:
The patent replaces the mechanical jig-based guidance system with a robotic control system. The robotic arm, controlled by pre-operative planning software and real-time tracking, substitutes for the physical jig, providing debris-free guidance while maintaining or improving cutting plane alignment accuracy
2Ease of operation
If the surgeon manually controls the oscillating surgical saw, then the surgery can be performed, but the difficulty in controlling the saw and limited visibility create risk of inaccurate cuts
Solution Approach 1:
The system enables semi-autonomous operation where the robotic arm automatically positions and guides the saw along the pre-planned cutting path, reducing the surgeon's manual control burden. The surgeon monitors the process and can intervene when needed, while the robotic system handles the precise positioning and guidance, improving both ease of operation and cutting accuracy
Solution Approach 2:
The system incorporates real-time tracking and feedback mechanisms that monitor the position of the robotic arm and saw blade, comparing actual positions against the pre-planned cutting path. This closed-loop feedback ensures accurate cuts while reducing the cognitive and manual burden on the surgeon, as the system self-corrects deviations automatically
3Productivity
If the surgical saw is used to cut bone, then the osteotomy can be performed, but vibrations generated by the saw reduce the accuracy of the cuts
Solution Approach 1:
The system uses an oscillating surgical saw that generates controlled vibrations at high frequency, which are necessary for efficient bone cutting. The robotic arm compensates for these vibrations through precise, real-time position adjustments, maintaining cutting accuracy despite the dynamic cutting process. The oscillation frequency and amplitude are optimized to balance cutting efficiency with vibration management
Data Source
AI summary
A passive end effector of a surgical system includes a base, a first mechanism, and a second mechanism. The base attaches to an end effector coupler of a robot arm positioned by a surgical robot. The first mechanism extends between a rotatable connection to the base and a rotatable connection to a tool attachment mechanism. The second mechanism extends between a rotatable connection to the base and a rotatable connection to the tool attachment mechanism. The first and second mechanisms pivot about the rotatable connections to constrain movement of the tool attachment mechanism to a range of movement within a working plane. The tool attachment mechanism is configured to connect to a surgical saw including a saw blade for cutting.