Micro-force guided cooperative control for delicate tissue manipulation
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Solution Overview
Problem
Retinal microsurgery is challenging due to human sensory-motor limitations, imprecise instruments, physiological hand tremor, poor visualization, and the difficulty of applying forces below sensory thresholds, leading to complications such as retinal damage and vision loss, as surgeons rely solely on visual cues for delicate maneuvers.
Innovation Solution
A cooperative control system for surgical tools that measures interaction forces between the tool tip and tissue, and between the surgeon and the tool handle, actively guiding the tool towards a path of least resistance by limiting directional forces and providing haptic feedback to prevent excessive force application.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If surgeons rely solely on visual cues to avoid excessive forces on retinal tissue, then they can perform delicate maneuvers, but surgical errors and complications may occur due to inability to sense imperceptible micro-force cues
Solution Approach 1:
The patent implements force feedback control where a robotic manipulator measures micro-forces applied to retinal tissue through a surgical tool and provides real-time feedback to the surgeon. This allows the surgeon to sense forces below human sensory thresholds through the robotic system, enabling continuous monitoring and adjustment to prevent retinal damage while maintaining intuitive control.
Solution Approach 2:
The robotic manipulator serves as an intermediary between the surgeon's hand and the retinal tissue. It measures forces at the tool-tissue interface and translates these imperceptible micro-forces into perceivable feedback signals, allowing the surgeon to indirectly sense tissue interaction forces that would otherwise be undetectable.
2Productivity
If surgeons manually perform peeling maneuvers with visual feedback only, then they can delaminate epiretinal membrane, but task completion time increases and continuous peel is interrupted
Solution Approach 1:
The robotic system provides real-time force feedback that enables continuous monitoring of tissue interaction during peeling. This allows the surgeon to maintain continuous peel without interruptions by detecting force changes that indicate membrane detachment status, enabling smoother and faster completion of the peeling procedure.
3Adaptability or versatility
If long thin surgical tools are inserted through sclera for retinal access, then surgical accessibility is achieved, but tool-sclera interference complicates measurement of tool-to-retina forces
Solution Approach 1:
The patent extracts the force measurement function from the surgical tool itself and places it in the robotic manipulator. By measuring forces at the tool handle rather than at the distal tip, the system eliminates interference from tool-sclera interactions, obtaining accurate retinal force measurements without requiring modification of the surgical tool.
4Ease of operation
If first generation steady-hand robot with ±30% tool rotation limit is used, then basic surgical tasks can be performed, but ergonomic limitations restrict tool rotation range
Solution Approach 1:
The patent employs dynamic control strategies that adapt the robot's motion constraints based on surgical task requirements. The control system dynamically adjusts tool rotation limits and motion parameters to maximize the effective workspace while maintaining surgical precision, allowing the system to achieve greater operational flexibility without physical hardware modifications.
Data Source
AI summary
A method and system for micro-force guided cooperative control that assists the operator in manipulating tissue in the direction of least resistance. A tool holder receives a surgical tool adapted to be held by a robot and a surgeon. A first sensor measures interaction forces between a tip of the surgical tool and tissue of a region of interest. A second sensor measures interaction forces between the surgeon and a handle to the surgical tool. A data processor is configured to perform an algorithm to actively guide the surgical tool by creating a bias towards a path of least resistance and limit directional tool forces of the surgical tool as a function of handle input forces and tip forces. This function offers assistance to challenging retinal membrane peeling procedures that require a surgeon to delicately delaminate fragile tissue that is susceptible to hemorrhage and tearing due to undesirable forces.