3D 2D Registration for Spinal Localization

Solution Overview

Problem

Wrong-site surgeries, particularly in spinal surgery, are common due to difficulties in localizing vertebrae in the mid-thoracic region using visual impressions, palpation, and fluoroscopic imaging, leading to errors and excessive radiation exposure for surgeons.

Innovation Solution

A method involving preoperative CT imaging, preprocessing to create a volume image, and intraoperative 2D X-ray imaging, followed by 3D/2D registration to generate a digitally reconstructed radiograph for correlation with the 2D image, allowing for automatic localization of structures like vertebrae, independent of the surgeon's ability to identify the target level.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If fluoroscopic counting is used to localize vertebral levels, then localization accuracy is improved, but radiation exposure to the surgeon increases and time consumption increases

Engineering Contradiction:

Improvelocalization accuracyVSAvoidradiation exposure

Core Design Contradiction:

Measurement precisionVSObject-affected harmful factors

Solution Approach 1:

The system performs preoperative CT imaging and 3D model creation before surgery, allowing the vertebral levels to be pre-identified and marked on the patient's body. This preliminary localization eliminates the need for repeated fluoroscopic counting during surgery, thereby reducing radiation exposure while maintaining accuracy.

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The invention introduces an optical tracking system and registered 3D model as an intermediary between the surgeon and the patient anatomy. Surgeons can visually identify pre-marked vertebral levels through optical guidance without direct fluoroscopic exposure, acting as a mediator that reduces harmful radiation while preserving measurement precision.

Inventive Principle:

Principle #24Intermediary (Mediator)

2Measurement precision

If fluoroscopic counting is used to localize vertebral levels, then localization accuracy is improved, but surgical time increases

Engineering Contradiction:

Improvelocalization accuracyVSAvoidsurgical time

Core Design Contradiction:

Measurement precisionVSLoss of time

Solution Approach 1:

The system performs preoperative CT imaging and 3D model creation before surgery, allowing the vertebral levels to be pre-identified and marked on the patient's body. This preliminary localization eliminates the need for repeated fluoroscopic counting during surgery, thereby reducing radiation exposure while maintaining accuracy.

Inventive Principle:

Principle #10Preliminary action

3Productivity

If visual impression and palpation are used to localize vertebrae, then surgical time is reduced, but localization accuracy deteriorates

Engineering Contradiction:

Improvesurgical efficiencyVSAvoidlocalization accuracy

Core Design Contradiction:

ProductivityVSMeasurement precision

Solution Approach 1:

The system performs preoperative CT imaging and 3D model creation before surgery, allowing the vertebral levels to be pre-identified and marked on the patient's body. This preliminary localization eliminates the need for repeated fluoroscopic counting during surgery, thereby reducing radiation exposure while maintaining accuracy.

Inventive Principle:

Principle #10Preliminary action

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

Significantly reduces the number of wrong-level surgeries and minimizes radiation exposure by enabling precise automatic localization of structures within 2D fluoroscopic images, improving surgical accuracy and safety.

Implementation Method 1

acquiring an intraoperative two dimensional (2D) X-ray image

Methodology Applied

Scientific EffectX-ray: X-Ray

Implementation Method 2

acquiring a preoperative computer-tomography (CT) image

Methodology Applied

Scientific EffectX-ray attenuation: X-Ray

Data Source

PatentUS11284846B2Method for localization and identification of structures in projection images

Publication Date: 2022.03.29 SIEMENS AG

AI summary

A method for localization and identification of a structure in a projection image with a system having a known system geometry, includes acquiring a preoperative computer-tomography or CT image of a structure, preprocessing the CT-image to a volume image, acquiring an intraoperative two dimensional or 2D X-ray image, preprocessing the 2D X-ray image to a fix image, estimating an approximate pose of the structure, calculating a digitally reconstructed radiograph or DRR using the volume image, the estimated pose and the system geometry, and calculating a correlation between the generated DRR and the fix image, with a correlation value representing matching between the generated DRR and the fix image. The method significantly decreases the number of wrong-level surgeries and is independent of the surgeon's ability to localize and/or identify a target level in a body.