Image-Guided Spinal Disc Positioning via CT-Fluoroscopy Registration
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Solution Overview
Problem
Current methods for accurately positioning artificial spinal discs during surgery are hindered by the difficulty in interpreting fluoroscope images due to soft tissue interference, leading to potential malpositioning, radiation exposure, and reliance on surgeon skill, which can result in pain, reduced mobility, and sometimes necessitate revision surgery or nerve damage.
Innovation Solution
An image-guided surgery system using preoperative CT data to create a virtual model of the spinal region, allowing for precise registration of fluoroscope images with CT data, enabling the projection of the optimal disc position onto real-time images, and utilizing specially designed K-wires with fiduciary markers for accurate three-dimensional positioning without obstructing the surgeon's view.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If fluoroscope images are used for real-time disc positioning, then the surgeon can observe the operating region dynamically, but the images are difficult to interpret clearly due to soft tissue interference and cannot clearly delineate midline positions
Solution Approach 1:
The patent introduces an image-guided surgery system that uses preoperative CT data as an intermediary reference. The system registers fluoroscope images with the preoperative CT model, using the CT data as a mediator to provide clear anatomical landmarks and midline positions that are not visible in fluoroscope images alone. This allows the surgeon to benefit from both real-time fluoroscopic observation and precise positioning guidance from the registered CT model.
Solution Approach 2:
The system creates a virtual copy of the patient's spinal anatomy from preoperative CT data. This virtual model is then registered with real-time fluoroscope images, providing a clear reference framework that copies the precise anatomical structures and midline positions. The surgeon can observe the operating region on fluoroscope images while simultaneously referencing the accurate anatomical copy from the registered CT model to achieve precise disc positioning.
2Ease of manufacture
If visual estimation from fluoroscope images is used for disc positioning, then the procedure is simple to perform, but the positioning accuracy is compromised leading to potential malpositioning
Solution Approach 1:
The registered preoperative CT model serves as an intermediary reference system that bridges the gap between simple fluoroscopic observation and precise positioning requirements. The system automatically registers the CT model with fluoroscope images, providing clear anatomical landmarks and midline positions without requiring complex manual navigation systems. This maintains procedural simplicity while significantly improving positioning accuracy through the intermediary CT reference.
3Measurement precision
If traditional navigation systems with optical reflectors on vertebrae are used, then positioning accuracy improves, but the system complexity increases and clear lines of sight must be maintained throughout the operation
Solution Approach 1:
The system performs the complex navigation setup work beforehand by acquiring preoperative CT data and creating a detailed virtual model of the patient's spinal anatomy. This preliminary action eliminates the need for complex intraoperative navigation hardware such as optical reflectors and continuous line-of-sight requirements. The preprocessed CT model is then registered with fluoroscope images, providing accurate positioning guidance without the complexity of traditional navigation systems during the actual surgery.
4Ease of operation
If the disc is not accurately positioned, then the surgical procedure is simpler, but excessive forces are applied to facet joints causing pain and potential nerve damage
Solution Approach 1:
The image-guided surgery system provides real-time feedback by registering fluoroscope images with the preoperative CT model. This feedback mechanism allows the surgeon to continuously monitor disc position relative to the accurate anatomical reference, ensuring proper positioning that avoids excessive forces on facet joints and nerves. The registered CT model serves as a feedback reference, guiding the surgeon to achieve optimal disc placement that maintains spinal biomechanics and prevents complications.
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 system significantly enhances the accuracy of disc placement, reduces radiation exposure, and minimizes strain on facet joints, ensuring optimal biomechanical positioning and reducing the risk of complications such as pain and nerve damage.
Implementation Method 1
at least one target having radio-opaque markers adapted to be attached to at least one of the vertebrae to define the position of the vertebra in at least one intra-operative fluoroscope image
Data Source
AI summary
A tracking and positioning system and method to enable the precise positioning of an object or tool relative to its surgical surroundings, and in accordance with preoperative CT images of the operating site. When used for artificial spinal disc positioning, the system comprises a computing system incorporating in memory the preoperative CT data showing the two vertebrae and the predetermined disc position between them; a 3-D target having radio-opaque markers for attaching to one of the vertebrae to define the position of the vertebra in an intra-operative fluoroscope image of the spine; a tool for intra-operative insertion of the artificial disc, and a registration system for relating the intra-operative fluoroscope image to the preoperative CT data, such that the predetermined disc position is displayed in the fluoroscope image of the subject, thereby enabling the surgeon to place the artificial disc accurately in its intended position.