Tele-Operated Surgery RCM Repositioning for Tissue-Safe Dexterity
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Solution Overview
Problem
Existing minimally invasive robotic surgery systems face challenges in controlling the motion of robotic manipulators and surgical instruments to prevent excessive lateral motion that can tear tissues or enlarge access sites, particularly when navigating complex or sensitive surgical environments.
Innovation Solution
Implementing software-constrained remote center of motion concepts using a processor to control the robotic manipulator assembly, allowing the remote center of motion to be located at various positions, including on the surgical instrument shaft or within patient tissue, and enabling controlled lateral and axial movements to maintain safe surgical access.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If the robotic manipulator is allowed to move freely to perform intricate surgical tasks, then the dexterity and versatility of the surgical system is improved, but the risk of tissue damage and trauma increases due to uncontrolled lateral motion
Solution Approach 1:
The system dynamically adjusts the remote center of motion (RCM) location based on surgical needs. The RCM is not fixed but can be repositioned by the processor in response to surgeon input, allowing the system to adapt between maintaining tissue safety (constrained motion) and achieving surgical dexterity (modified motion constraints) throughout the procedure
Solution Approach 2:
The system changes the motion constraint parameters by relocating the RCM to different positions. This parameter change allows the manipulator to transition between different motion regimes - from highly constrained when tissue protection is priority to more flexible when surgical manipulation is priority
2Object-affected harmful factors
If the remote center of motion is fixed to constrain lateral motion and protect tissue, then tissue stress and trauma are reduced, but the ability to modify surgical working space and enhance access is limited
Solution Approach 1:
The RCM location is made dynamic rather than fixed. The processor can reposition the RCM to different locations in response to surgeon input, enabling the system to modify the surgical working space when needed while maintaining tissue protection as the default state
Solution Approach 2:
The system incorporates feedback mechanisms where the surgeon can provide input to reposition the RCM. This feedback loop allows the system to respond to changing surgical requirements, adjusting motion constraints to enhance working space access when the surgeon determines it is safe to do so
3Ease of operation
If software constraints are used to control robotic manipulator motion instead of mechanical constraints, then the ease of operation and reconfigurability are improved, but the system complexity increases
Solution Approach 1:
The system replaces complex mechanical motion constraint mechanisms with software-based control. Instead of physical linkages and mechanical stops that would be needed to enforce RCM constraints, the system uses a processor to calculate and enforce motion constraints through control algorithms, simplifying the mechanical design while maintaining operational precision
Solution Approach 2:
The software control system serves multiple functions: it enforces motion constraints to protect tissue, allows dynamic repositioning of the RCM, and provides the interface for surgeon input. This multi-functionality consolidates what would otherwise require separate mechanical subsystems into a unified software-based control architecture
Data Source
AI summary
A computer-assisted system includes a manipulator assembly configured to couple to a cannula at a distal portion of the manipulator assembly. The cannula has a lumen configured to receive a shaft of an instrument. A cannula axis is aligned with the cannula when the cannula is coupled to the manipulator assembly. An instrument axis is aligned with the instrument when the instrument is coupled to the manipulator assembly. A controller coupled to the manipulator assembly is configured to receive an indication to reposition a remote center of motion (RCM) for the manipulator assembly while the RCM is positioned at a first location relative to the distal portion along an axis, wherein the axis is aligned with the cannula axis or the instrument axis; and in response to receiving the indication, cause the RCM to be positioned at a second location relative to the distal portion along the axis.