End Effector Collision Modeling for Low-Latency Surgical Tracking

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Solution Overview

Problem

Existing surgical navigation systems face computational challenges in accurately tracking non-spherical surgical instruments relative to patient boundaries in real time, leading to undesirable latency and potential compromises in precision.

Innovation Solution

A surgical navigation system that includes a handheld surgical instrument with an end effector, a localizer, and a control system to associate an end effector model with a security margin, allowing for precise tracking and collision detection with patient boundaries, using a modified end effector model to provide real-time alerts through an alert module.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If a detailed end effector model is used for accurate tracking, then measurement precision is improved, but computational expense increases causing latency

Engineering Contradiction:
Improvetracking precisionVSAvoidcomputational latency
Core Design Contradiction:
Measurement precisionVSLoss of time

Solution Approach 1:

The end effector model is segmented into a collision sphere and a collision capsule, each handling different aspects of collision detection. The collision sphere represents the distal tip for precise boundary interaction, while the collision capsule extends along the longitudinal axis for efficient volumetric collision checks, dividing the complex modeling task into manageable geometric primitives

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

A simplified collision capsule geometry is created as a computational copy of the actual end effector. This capsule version maintains the essential longitudinal extent for collision detection purposes while using a simpler geometric representation that enables faster real-time computational processing compared to detailed mesh models

Inventive Principle:
Principle #26Copying

2Reliability

If real-time collision detection is implemented, then surgical safety is improved, but computational resources are consumed

Engineering Contradiction:
Improvesurgical safetyVSAvoidcomputational energy
Core Design Contradiction:
ReliabilityVSUse of energy by moving object

Solution Approach 1:

Collision detection is segmented into two hierarchical levels: first, a fast bounding volume check using the collision capsule to quickly eliminate non-colliding configurations, and second, a more precise but computationally intensive check using the collision sphere only when the capsule indicates potential overlap, reducing overall computational energy consumption while maintaining safety

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The system performs partial collision detection by using the simplified collision capsule for routine safety monitoring and only activating the more computationally demanding precise detection algorithms when the capsule indicates a potential collision event, avoiding excessive computational energy expenditure while maintaining adequate safety monitoring

Inventive Principle:
Principle #16Partial or excessive action

Data Source

PatentEP4652950A1System for reducing latency during tracking a handheld surgical instrument using mesh to mesh collisions and a modified end effector model
Publication Date: 2025.11.26 STRYKER EUROPEAN OPERATIONS LIMITED
  • EP4652950A1 patent drawingFigure 1
  • EP4652950A1 patent drawingFigure 2
  • EP4652950A1 patent drawingFigure 3

AI summary

A surgical navigation system is provided, which includes a handheld surgical instrument configured to receive an end effector, a localizer configured to determine a pose of the handheld surgical instrument, an alert module for providing notifications to a user, and a control system in communication with the localizer and the alert module. The control system configured to receive a selection of the end effector, associate an end effector model with the handheld surgical instrument based on the selection of the end effector, receive a selection of a security margin, modify a spatial dimension of the end effector model based on the selected security margin, determine a pose of the modified end effector model, determine a pose of a patient boundary associated with a target anatomical feature, and control the alert module based on the pose of the patient boundary and the pose of the modified model of the end effector.