Optical Fiber Shape Sensing for Surgical Tool Alignment
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Solution Overview
Problem
Current methods for targeting non-visible features during orthopedic surgery, such as intramedullary nail alignment, face challenges including inaccurate positional calculations due to metallic interference in magnetic field sensing and increased costs from dual navigation systems, and expose surgical staff to radiation with x-ray-based methods.
Innovation Solution
A shape-sensing system using optical fibers with Fiber Bragg Gratings (FBGs) that provides precise 3D position and orientation data, allowing for accurate alignment of surgical tools to target features by comparing tool and target reference frames, potentially reducing radiation exposure and navigation system errors.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If magnetic field sensors are used to track the position of surgical tools, then position sensing can be achieved, but metallic objects in the magnetic field volume significantly influence data accuracy and cause positioning errors
Solution Approach 1:
The patent replaces magnetic field-based sensing with an optical fiber shape sensing system that uses light propagation and Fiber Bragg Gratings to detect position and orientation. This substitution eliminates the harmful interaction between magnetic fields and metallic surgical instruments, as the optical system is immune to metallic interference.
Solution Approach 2:
The patent introduces optical fibers with Fiber Bragg Gratings as an intermediary sensing mechanism within the intramedullary rod. These FBGs act as distributed sensors that reflect specific wavelengths of light corresponding to their strain state, providing position information without requiring external magnetic fields that would be distorted by metallic objects.
2Measurement precision
If iterative x-ray imaging with C-arm is used to target distal fixation holes, then positioning can be achieved, but surgical staff and patients are exposed to elevated radiation levels
Solution Approach 1:
The patent replaces radiation-based C-arm imaging with an optical fiber sensing system that uses light propagation through optical fibers. This substitution eliminates ionizing radiation exposure while providing continuous, real-time position data of the surgical tool relative to the implanted rod, enabling accurate targeting without repeated x-ray exposures.
Solution Approach 2:
The optical fiber shape sensing system provides self-contained position information within the surgical field. The FBGs embedded in the optical fiber automatically detect and report their position and orientation changes as the surgical tool moves, eliminating the need for external imaging equipment and radiation exposure.
3Measurement precision
If dual navigation systems are used to compensate for magnetic field interference, then positioning accuracy can be maintained, but system complexity and cost increase significantly
Solution Approach 1:
The patent replaces complex dual navigation systems with a single, integrated optical fiber shape sensing system. By substituting the magnetic field-based external navigation with internal optical sensing, the system achieves comparable or superior accuracy without requiring multiple independent navigation systems, thereby reducing overall complexity.
Solution Approach 2:
The patent combines position, orientation, and shape sensing capabilities into a single optical fiber system with embedded Fiber Bragg Gratings. This merging of multiple sensing functions into one integrated system eliminates the need for separate magnetic navigation systems and their associated complexity, while providing comprehensive positional information.
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
Enhances the accuracy and reliability of aligning surgical tools to target features, reducing radiation exposure and navigation errors, while minimizing system complexity and cost.
Implementation Method 1
A shape-sensing system using optical fibers with Fiber Bragg Gratings (FBGs) that provides precise 3D position and orientation data
Data Source
AI summary
A system for targeting a feature on a surgical device, includes a shape sensing element coupled to an interrogator and operable to provide information to related to said portion's position in a reference frame in communication with the targeted feature. The interrogator is operable to poll the shape sensing element for information related to said portion's position in the reference frame. A surgical tool is coupled to the targeting system in communication with the shape sensing element. The data processor is operable to communicate with the interrogator to output position information of the portion of the shape sensing element with respect to a calibrated position, defined as the position of the portion of the shape sensing element in the reference frame when the guide axis is aligned to the targeted feature. A display provides the user visual information comparing the position of the tool to the targeted feature.