Pedicle Screw Placement Using 3D CT Reconstruction

Resolve Bottlenecks,
Find Innovative Solutions
Generate Solutions

Solution Overview

Problem

Current methods for determining the optimal direction and sizing of pedicle screws in pedicle arthrodesis surgeries lack precision, leading to potential irreversible damage due to incorrect placement, as they either rely on user-defined sections or fail to accurately identify the maximum bone material points for screw insertion.

Innovation Solution

A computer-aided method using three-dimensional CT or NMR reconstructions to identify the optimal direction and maximum diameter of pedicle screws by selecting a point P on the pedicle, generating a spherical cap, and calculating the centroid and minimum distance for screw placement, which is then used to create a personalized template for precise surgical guidance.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of operation

If user-defined sections or conventional methods are used to determine screw placement, then the process is simpler, but the precision and accuracy of screw placement deteriorates

Engineering Contradiction:
Improvesimplicity of screw placement determinationVSAvoidprecision of screw placement
Core Design Contradiction:
Ease of operationVSMeasurement precision

Solution Approach 1:

The patent replaces manual measurement and visual estimation methods with a computerized system that processes 3D medical images (CT or NMR scans). The computer automatically calculates the optimal screw trajectory, diameter, and placement points by analyzing the 3D vertebral geometry, substituting the mechanical/manual process with an automated computational approach that delivers both precision and ease of use.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The system creates a digital 3D replica of the patient's vertebral anatomy from medical imaging data. This virtual model allows for precise measurement and planning of screw placement without requiring direct manual measurement on the patient's anatomy, enabling accurate pre-surgical planning that can be easily transferred to the actual surgical procedure.

Inventive Principle:
Principle #26Copying

2Loss of time

If conventional methods are used for determining optimal screw direction, then the procedure is faster, but the safety and reliability of the procedure deteriorates

Engineering Contradiction:
Improvetime for screw placement planningVSAvoidsafety of screw placement
Core Design Contradiction:
Loss of timeVSReliability

Solution Approach 1:

The system performs comprehensive screw placement planning before the actual surgery by analyzing 3D vertebral anatomy and calculating optimal trajectories, directions, and diameters in advance. This preliminary computational analysis identifies the safest placement parameters, allowing surgeons to proceed with confidence during the actual procedure without time-consuming intraoperative adjustments, thus improving both speed and reliability.

Inventive Principle:
Principle #10Preliminary action

3Device complexity

If manual methods are used to identify maximum bone material points, then the process is simpler, but the manufacturing precision of screw placement deteriorates

Engineering Contradiction:
Improvecomplexity of placement determinationVSAvoidprecision of hole placement
Core Design Contradiction:
Device complexityVSManufacturing precision

Solution Approach 1:

The patent replaces manual identification of optimal bone material points with automated computer-based analysis of 3D vertebral geometry. The system calculates precise coordinates for maximum bone engagement points by processing the digital model, eliminating the need for complex manual measurements and providing high-precision placement guidance that improves manufacturing precision without proportionally increasing operational complexity.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

Data Source

PatentEP3120797B1Method for identifying the optimal direction and maximum diameter of a pedicle screw
Publication Date: 2019.09.04 TECHNODESIGN
  • EP3120797B1 patent drawingFigure 1
  • EP3120797B1 patent drawingFigure 2

AI summary

The vertebral motor unit is, as any part of the body, exposed to the possibility of degenerative pathological conditions that may cause structural disorder. In the cases of pathological conditions in which the correction through appropriate devices or physiotherapy is not sufficient for cure, it is indispensable to carry out an operation known as "pedicle arthrodesis". Pedicle arthrodesis is a surgical technique that consists in fixation of one or more joints of the vertebral column. Usually, the operation is performed by means of implants to be fixed to the vertebral column by hooking them to pedicle screws anchored to the vertebrae. The screws are inserted by previously making in the vertebra two lateral holes, using a surgical perforating implement. The present invention has the purpose of identifying, with the aid of a computer and on an x-ray, or on a three-dimensional reconstruction by means of CT or NMR, generated by a computer, hence without ever coming into contact in vivo with the patient, the optimal direction and the maximum diameter of a pedicle screw so that the screw will not come out of the pedicle.