Image-Guided Spinal Surgery Tool Tracking via 3D-2D Registration
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Solution Overview
Problem
Current spinal surgery techniques rely heavily on fluoroscopic guidance, which exposes patients and staff to significant radiation, and require expensive Computer Aided Surgery (CAS) systems that limit tool selection and increase procedural costs due to the need for location sensors and calibration.
Innovation Solution
A method and apparatus that utilize 3D image data acquired pre-intervention and 2D radiographic images during intervention to register the location of surgical tools relative to the spine, using radiopaque markers and a computer processor to overlay tool paths on 3D images without the need for real-time tracking or calibration, allowing for precise tool placement and reduced radiation exposure.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If fluoroscopic guidance is used for real-time imaging during surgery, then surgical guidance is improved, but radiation exposure to patient and staff increases significantly
Solution Approach 1:
The system performs pre-operative 3D imaging (CT or MRI) to create a detailed anatomical model of the patient's spine and pathology. This preliminary action captures all necessary surgical planning information before the patient enters the operating room, eliminating the need for continuous fluoroscopic imaging during the procedure and thereby reducing radiation exposure while maintaining surgical guidance accuracy.
Solution Approach 2:
The system creates a virtual copy of the patient's anatomy through 3D reconstruction from pre-operative images. This digital twin includes the spine, pathology, and planned instrumentation trajectories. Surgeons interact with this virtual model instead of relying on real-time fluoroscopy, achieving the same guidance function without radiation exposure.
2Measurement precision
If Computer Aided Surgery (CAS) systems with location sensors are used for navigation, then surgical precision is improved, but system cost and procedural complexity increase
Solution Approach 1:
The system extracts and eliminates the complex tracking infrastructure required by traditional CAS systems. Instead of using electromagnetic trackers, optical cameras, and location sensors attached to tools and anatomy, this invention uses purely 2D fluoroscopic images registered to the pre-operative 3D model, removing all associated hardware and calibration requirements while maintaining navigation precision.
Solution Approach 2:
The system replaces expensive, reusable CAS navigation equipment with a simpler, image-based approach that uses standard fluoroscopic imaging equipment already present in most operating rooms. The navigation solution is generated software-based from existing images, eliminating the need for costly proprietary hardware systems.
3Measurement precision
If CAS systems require location sensors and calibration procedures, then tool tracking accuracy is improved, but procedural time and cost increase
Solution Approach 1:
All calibration and registration work is performed pre-operatively when creating the 3D anatomical model and planning the surgery. The system pre-calculates transformation matrices between the patient's anatomy and the surgical coordinate system. During the actual surgery, no calibration is needed—surgeons simply acquire fluoroscopic images that are automatically registered to the existing plan, eliminating time-consuming setup procedures.
Solution Approach 2:
The system uses the fluoroscopic images themselves as the tracking reference, eliminating the need for separate location sensors on surgical tools. The tools appear naturally in the fluoroscopic images, and their positions are determined directly from the image geometry and pre-calculated transformation matrices, making the system self-sufficient without external tracking infrastructure.
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
This approach enables precise and cost-effective spinal surgery by reducing radiation exposure and eliminating the need for expensive CAS systems, while allowing for accurate tool placement and visualization of tool paths within the surgical field.
Implementation Method 1
generating a plurality of 2D projections from the 3D image data, and identifying a 2D projection that matches the 2D radiographic image of the skeletal portion
Data Source
AI summary
3D image data of a skeletal portion is acquired. While a portion of a tool is disposed at a first location along an insertion path, first and second x-rays are acquired from first and second image views. A processor registers the x-rays with the 3D image data, identifies a location of a tool within the x-rays, and computes an anticipated forward path of the tool within the 3D image data from the x-rays. The tool is moved to a second location along the insertion path and an additional x-ray is acquired from a single image view. The processor facilitates identifying if the tool has deviated from the anticipated forward path by registering the additional x-ray to the 3D image data and identifying a location of the portion of the tool within the additional x-ray. Other embodiments are also described.