Virtual Constraint Boundaries for Moving Objects in Robotic Surgery

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Solution Overview

Problem

Existing robotic surgery systems face challenges in accurately tracking dynamic virtual boundaries for anatomical features and objects that move relative to the anatomy being treated, leading to potential damage to the end effector or displacement of retractors.

Innovation Solution

A surgical system incorporating a robotic manipulator, navigation system, machine vision system, and control system to detect and associate virtual boundaries with moving objects, controlling the manipulator to avoid these objects by dynamically tracking their movement.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If virtual boundaries are fixed with respect to the bone model prior to surgery, then the navigation system can track movement of the virtual cutting boundary by tracking movement of the bone, but the system cannot accurately track dynamic virtual boundaries for objects that move relative to the anatomy being treated

Engineering Contradiction:

Improvetracking accuracy of virtual boundariesVSAvoidability to track moving objects

Core Design Contradiction:

Measurement precisionVSAdaptability or versatility

Solution Approach 1:

The system transitions from static virtual boundaries fixed to the bone model to dynamic virtual boundaries that can track moving objects in real-time. The machine vision system continuously updates the position and orientation of retractors and other movable objects, allowing the virtual boundaries to adapt dynamically during surgery rather than remaining fixed preoperatively.

Inventive Principle:

Principle #15Dynamics

Solution Approach 2:

The system implements continuous feedback through the machine vision system that monitors the positions of movable objects and feeds this information back to the navigation system. This feedback loop enables real-time adjustment of virtual boundaries to match the actual positions of retractors and other objects, ensuring accurate tracking throughout the surgical procedure.

Inventive Principle:

Principle #23Feedback

2Productivity

If the end effector is allowed to move freely without dynamic constraint boundaries, then the surgical procedure can proceed efficiently, but the end effector may inadvertently strike moving retractors causing damage or displacement

Engineering Contradiction:

Improvesurgical efficiencyVSAvoidsafety of surgical instruments

Core Design Contradiction:

ProductivityVSReliability

Solution Approach 1:

The constraint boundaries transition from static preoperative plans to dynamic real-time boundaries that move with the retractors. This allows the end effector to move freely within safe zones while automatically adapting constraints when retractors are repositioned, maintaining surgical efficiency without compromising instrument safety.

Inventive Principle:

Principle #15Dynamics

Solution Approach 2:

The system proactively prevents potential collisions by establishing virtual constraint boundaries before the end effector can inadvertently strike retractors. The machine vision system continuously monitors retractor positions and preemptively adjusts boundaries to guide the end effector away from potential hazard zones, preventing damage before it occurs.

Inventive Principle:

Principle #9Preliminary anti-action

3Device complexity

If traditional navigation systems are used without machine vision, then the system is simpler, but it cannot detect and track moving objects like retractors to create dynamic virtual boundaries

Engineering Contradiction:

Improvesystem complexityVSAvoiddetection capability of moving objects

Core Design Contradiction:

Device complexityVSMeasurement precision

Solution Approach 1:

The system merges traditional navigation systems with machine vision technology to create an integrated solution. The machine vision system detects and tracks movable objects, while the navigation system processes this information to create and update virtual boundaries, combining the strengths of both approaches to achieve accurate dynamic tracking.

Inventive Principle:

Principle #5Merging (Combining)

Solution Approach 2:

The machine vision system acts as an intermediary between the physical retractors and the navigation system. It captures images of the surgical field, identifies retractor positions, and translates this visual information into coordinate data that the navigation system can use to create accurate virtual boundaries, bridging the gap between optical detection and navigational control.

Inventive Principle:

Principle #24Intermediary (Mediator)

Data Source

PatentUS20250345126A1Systems And Methods For Establishing Virtual Constraint Boundaries

Publication Date: 2025.11.13 STRYKER CORP

AI summary

Surgical systems and methods of operating the same involve controlling a robotic manipulator to move a cutting instrument to manipulate a bone at a surgical site. A navigation system has a localizer to track poses of a tracker coupled to a bone at a surgical site. A machine vision system has a vision camera. A control system is coupled to the robotic manipulator, the navigation system, and the machine vision system. The control system detects, with the machine vision system, an object at, or in proximity to, the surgical site and associate a virtual boundary with the detected object. The control system controls the robotic manipulator to move the cutting instrument to manipulate the bone based on the tracked poses of bone. The control system controls the robotic manipulator to constrain movement of the cutting instrument based on the virtual boundary such that the cutting instrument avoids the object.