Fiber Optic Tracking System for Surgical Tissue Deformation

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Solution Overview

Problem

Conventional fiber optic tracking systems for surgical procedures lack accuracy and high sampling rates, and are invasive, failing to robustly track tissue positions during surgeries, especially when surgical instruments with sharp edges may inadvertently damage soft tissue.

Innovation Solution

A fiber optic tracking system with optical fibers having fixed sensing points relative to a surgical port, which is inserted into an incision, allowing the system to determine tissue deformation and shape accurately, using modified optical signals to calculate the pose and location of the tissue in a working coordinate system, without the need for invasive pins or line of sight vision tracking.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If conventional fiber optic tracking systems are used, then tracking capability is provided, but accuracy and sampling rate are insufficient

Engineering Contradiction:
Improvetracking accuracyVSAvoidtracking reliability
Core Design Contradiction:
Measurement precisionVSReliability

Solution Approach 1:

The optical fiber is divided into multiple sensing sections along its length, each capable of independent strain measurement. This segmentation allows the system to track multiple points on the tissue simultaneously, improving both accuracy through multiple measurement points and reliability through redundant data

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The system transitions from conventional single-point or limited-point tracking to three-dimensional shape sensing by distributing multiple sensing sections along the optical fiber. This enables comprehensive spatial tracking of tissue deformation in three dimensions, significantly improving measurement precision

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

2Stability of the object's composition

If bone screws or invasive methods are used for coupling to hard tissue, then tracking stability is improved, but tissue damage risk increases

Engineering Contradiction:
Improvetracking stabilityVSAvoidtissue damage
Core Design Contradiction:
Stability of the object's compositionVSObject-affected harmful factors

Solution Approach 1:

The optical fiber acts as an intermediary sensing element that can be inserted through a small incision without requiring invasive anchoring to hard tissue. The fiber's flexibility allows it to conform to soft tissue contours while maintaining stable optical coupling for tracking, eliminating the need for bone screws or other invasive fixation methods

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The optical fiber serves as a flexible sensing element that can adapt to the contours of soft tissue without rigid fixation. This flexibility enables stable tracking through soft tissue deformation while avoiding the tissue damage associated with rigid invasive anchoring methods

Inventive Principle:
Principle #30Flexible shells and thin films

3Productivity

If sharp surgical instruments are used inside incision, then surgical tasks are performed, but soft tissue damage risk increases

Engineering Contradiction:
Improvesurgical task completionVSAvoidsoft tissue damage
Core Design Contradiction:
ProductivityVSObject-affected harmful factors

Solution Approach 1:

The optical fiber provides real-time feedback on the position and shape of the incision and surrounding soft tissue during surgical procedures. This continuous monitoring enables the surgical system to adjust instrument paths and avoid accidental contact with soft tissue, maintaining productivity while preventing damage

Inventive Principle:
Principle #23Feedback

Applied Scientific Principles

This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.

Function Achieved in This Case

The system provides accurate, non-invasive tracking of tissue and incision shapes, preventing damage to soft tissue by ensuring surgical instruments stay within the surgical port's central aperture, enhancing surgical precision and safety.

Implementation Method 1

One type of sensing section, called a fiber Bragg grating, reflects a certain wavelength of light depending in part upon the strain experienced by the optical fiber at the sensing section

Methodology Applied
Scientific EffectFiber Bragg grating reflection: Reflection

Implementation Method 2

each fiber core has an associated Rayleigh scatter signature and different segments of each fiber core correspond to a portion of the associated Rayleigh scatter signature

Methodology Applied
Scientific EffectRayleigh scattering: Rayleigh Scattering

Data Source

PatentEP3709922B1Fiber optic tracking system
Publication Date: 2024.10.02 MAKO SURGICAL CORP
  • EP3709922B1 patent drawingFigure 1
  • EP3709922B1 patent drawingFigure 2
  • EP3709922B1 patent drawingFigure 3

AI summary

A fiber optic tracking system includes a light source, a first optical fiber, a second optical fiber, a sensing unit, and a controller operatively coupled to the sensing unit. Each optical fiber includes a plurality of sensing sections and has a fixed sensing point located along its respective length that is fixed relative to tissue. Each optical fiber is configured to receive an optical signal from the light source. The sensing sections are configured to modify the optical signals in response to a deformation of the respective optical fiber. The sensing unit is configured to receive modified optical signals from the first optical fiber and the second optical fiber. The controller is configured to determine locations in a working coordinate system of the fixed sensing points using the modified optical signals and determine a pose of the tissue based on the locations of the fixed sensing points.