Pedicle Screw Fixation Planning Using C-Arm Imaging
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Solution Overview
Problem
Current pedicle screw fixation planning relies on CT images, which expose patients to harmful radiation and require cumbersome image registration with C-arm images, while C-arm images are not suitable for planning due to lack of axial views, limiting flexibility and accuracy during surgery.
Innovation Solution
A system and method using a C-arm to capture spinal images, determining entry and insertion points, calculating spatial coordinates, guiding a probe, and determining screw length based on C-arm images, eliminating the need for CT images and reducing radiation exposure by enabling flexible and accurate planning during surgery.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If CT images are used for pedicle screw fixation planning, then axial view and planning accuracy are provided, but radiation exposure harm and image registration complexity increase
Solution Approach 1:
The patent creates a virtual 3D model (copy) of the patient's anatomy from preoperative CT data, then uses this model for planning. During surgery, the plan is transferred to the actual patient using surface registration, eliminating the need for intraoperative CT scans and reducing radiation exposure while maintaining planning accuracy.
Solution Approach 2:
All planning activities including screw trajectory selection, length determination, and depth calculation are performed preoperatively using CT images. This preliminary planning is then transferred to the operating room using surface registration, avoiding the need for harmful intraoperative CT scans while maintaining the benefits of accurate preoperative planning.
2Measurement precision
If CT images are used for pedicle screw fixation planning, then axial view is provided, but image registration complexity with C-arm increases
Solution Approach 1:
The patent creates a virtual 3D model from preoperative CT data and performs all planning on this model. During surgery, only surface registration is required to transfer the preoperative plan to the actual patient anatomy, dramatically simplifying the registration process compared to registering full 3D CT volumes with intraoperative C-arm images.
Solution Approach 2:
The patent extracts only the essential planning information (screw trajectories, lengths, depths) from the preoperative CT-based virtual model and transfers this extracted data to the operating room using simple surface registration, eliminating the need for complex 3D-3D or 3D-2D image registration of full volumetric datasets.
3Object-affected harmful factors
If C-arm images are used for planning, then radiation exposure is reduced and registration with C-arm is eliminated, but axial view and planning capability are lost
Solution Approach 1:
The patent performs all detailed planning activities preoperatively when CT images are available, including selecting optimal screw trajectories, determining lengths, and calculating depths. This preliminary planning captures all necessary precision information before surgery, allowing the use of simpler, lower-radiation C-arm imaging during the actual procedure without compromising planning accuracy.
Solution Approach 2:
The patent creates a complete virtual surgical plan preoperatively using CT-based 3D modeling. This virtual plan serves as a copy of the intended surgery that can be executed in the operating room using simple surface registration with C-arm imaging, transferring the precision of preoperative planning to the surgical environment without requiring intraoperative CT scans.
4Adaptability or versatility
If C-arm images are used for planning, then registration with CT is eliminated and surgical flexibility is improved, but axial view and comprehensive spinal visualization are lost
Solution Approach 1:
The patent performs comprehensive spinal visualization and planning preoperatively using CT-based 3D modeling when all anatomical structures are clearly visible. The detailed plan including screw trajectories, lengths, and depths is determined at this stage when complete anatomical information is available, then transferred to the operating room where surgical flexibility can be maximized without needing repeated imaging.
Solution Approach 2:
The patent creates a complete virtual model and surgical plan preoperatively that captures all necessary anatomical information and surgical parameters. This virtual copy contains all the spinal structure visualization information needed, allowing the surgeon to execute the plan with maximum flexibility during surgery without requiring intraoperative CT scans or complex image registration.
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 reduces patient radiation exposure, simplifies surgical procedures, and allows for real-time adjustments and improved accuracy in navigating surgical tools by using C-arm images for pedicle screw fixation planning, enhancing the surgical process.
Implementation Method 1
a C-arm configured to capture a spinal image of a patient
Data Source
AI summary
A system for planning pedicle screw fixation includes: a C-arm configured to capture a spinal image of a patient; an insertion path provider configured to provide an entry point and an insertion endpoint of a pedicle screw on a C-arm image; a registrator configured to calculate spatial coordinates of the entry point and the insertion endpoint based on a reference coordinate system; a guider configured to determine an insertion position of the pedicle screw based on the spatial coordinates of the entry point and the insertion endpoint, and guide a probe to be inserted toward the entry point according to the insertion positions; and a screw determiner configured to determine a length condition of the pedicle screw by obtaining coordinates of a start point at which the probe is inserted and becomes in contact with a bone.