Pedicle Screw Trajectory Planning Using 3D Spine Imaging
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Solution Overview
Problem
Current spinal surgery methods lack a reliable and automated method for accurately determining pedicle diameter, length, and trajectory for instrument or screw placement, which is crucial for procedures like vertebroplasty, kyphoplasty, and pedicle screw placement, often relying on manual determination and radiographic imaging.
Innovation Solution
A system that uses CT or MRI scans to generate three-dimensional images of the spine, allowing for automatic calculation of maximum pedicle diameter and screw length, and provides schematic diagrams for precise instrument or screw placement, offering manual, semi-automated, or fully automated methods, including extraosseous options, to ensure safe and reproducible access to vertebral bodies.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If manual determination methods are used for pedicle diameter, length and trajectory, then device complexity is reduced, but measurement precision and manufacturing precision deteriorate
Solution Approach 1:
The patent creates a digital 3D copy of the patient's spine anatomy from CT or MRI scans. This virtual model allows automated measurement of pedicle dimensions and trajectory without requiring complex physical measurement devices during surgery. The digital model serves as a precise replica that can be analyzed repeatedly with high accuracy.
Solution Approach 2:
The patent replaces manual mechanical measurement methods with computer-automated digital measurement systems. The 3D imaging software automatically calculates pedicle diameter, length, and trajectory parameters from volumetric data, eliminating the need for manual radiographic analysis and physical trial instruments.
2Measurement precision
If extensive radiographic imaging is performed to ensure accurate placement, then measurement precision improves, but loss of time and loss of energy increase
Solution Approach 1:
The patent performs all necessary measurements and planning actions before the surgical procedure using preoperative CT or MRI scans. The 3D model is created and measured in advance, allowing the surgeon to plan the exact approach, entry point, and instrument length before entering the operating room, thereby eliminating the need for extensive intraoperative imaging.
Solution Approach 2:
The patent uses a digital 3D copy of the spine anatomy from preoperative scans to perform all necessary measurements and trajectory calculations. This virtual model provides persistent, repeatable access to anatomical data without requiring repeated radiographic imaging during the procedure.
3Manufacturing precision
If automated calculation methods are used for pedicle parameters, then manufacturing precision improves, but device complexity increases
Solution Approach 1:
The patent creates a digital 3D copy of the patient's spine from standard CT or MRI scans. This virtual model serves as the basis for automated calculation of all pedicle parameters including diameter, length, and trajectory angles, enabling precise instrument and screw selection without requiring complex specialized equipment.
Solution Approach 2:
The patent uses a universal 3D imaging software platform that can process various input formats (CT, MRI) and perform multiple functions including measurement, trajectory calculation, and surgical planning. This multi-functional approach reduces overall system complexity compared to having separate specialized devices for each measurement task.
4Ease of operation
If transpedicular approach is used for vertebral body access, then ease of operation improves, but object-affected harmful factors increase due to risk of iatrogenic injury
Solution Approach 1:
The patent performs comprehensive preoperative planning using 3D imaging and automated measurement to determine the optimal transpedicular approach parameters before surgery. By calculating the precise entry point, angle, and instrument length in advance based on the patient's unique anatomy, the surgeon can execute the procedure with greater confidence and precision, reducing the risk of cortical breach and spinal cord injury.
Solution Approach 2:
The patent incorporates the ability to review and verify calculated parameters against the 3D anatomical model before proceeding with the procedure. The system allows verification of trajectory and depth measurements, providing a feedback mechanism that ensures the planned approach is safe and appropriate for the patient's specific anatomy, thereby reducing iatrogenic harm.
Data Source
AI summary
A method of determining the size and/or placement of screws or other instruments in pedicles during surgery in a selected spinal area, comprising generating a dimensionally true three-dimensional image of the bony spine in the selected spinal area; hollowing out the vertebra in the three-dimensional image with cortical wall thicknesses selected by a surgeon performing the surgery; determining the narrowest cross section (isthmus) within each pedicle; generating a straight line starting at the center of the isthmus and extending inwardly to a point centered within the anterior cortex so that it is positioned concentrically within the pedicle without touching the walls thereof, the line terminating inside the vertebral body a predetermined distance from the anterior inner cortical wall and extending outwardly in the opposite direction to penetrate the posterior pedicle cortex; expanding the line concentrically and radially to a cross sectional size that is less than that of the isthmus, the line being expanded into a cylinder that stops growing when any portion thereof contacts the inner cortical wall of the hollowed out vertebral body, with the exception of the posterior pedicle cortex; and calculating the ideal pedicle screw or instrument diameter, length and/or trajectory based on the dimensions and trajectory of the cylinder generated for each pedicle. Also, a new and improved method for providing access to the interior of a pedicle for a desired transpedicular procedure, and a new and improved pedicle cannula construction are disclosed herein.