Patient-Specific Pedicle Screw Rod Shape from 3D Spine Modeling

Resolve Bottlenecks,
Find Innovative Solutions
Generate Solutions

Solution Overview

Problem

Existing methods for bending rods during spinal fusion surgeries are cumbersome and difficult to perform accurately, requiring significant time and expertise, as they rely on freehand adjustments without precise consideration of patient-specific anatomical parameters.

Innovation Solution

A method involving pre-operative planning using bidimensional and tridimensional imaging, segmentation, and virtual modeling to calculate a patient-specific rod shape, incorporating spino-pelvic parameters and screw placements, ensuring optimal curvature and alignment.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If freehand rod bending is performed during surgery, then the rod can be adapted to patient anatomy, but the surgical time increases and accuracy decreases

Engineering Contradiction:
Improverod curvature accuracyVSAvoidsurgical operating time
Core Design Contradiction:
Manufacturing precisionVSLoss of time

Solution Approach 1:

The patent performs pre-operative planning and rod shape calculation before surgery using patient-specific imaging data (CT or MRI). The optimal rod curvature and screw positions are determined in advance through virtual modeling, allowing the rod to be pre-bent or 3D-printed with the exact required shape, eliminating time-consuming intraoperative bending while maintaining high precision

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The patent creates a virtual copy of the patient's spine anatomy through imaging and segmentation to simulate and calculate the optimal rod shape in silico. This digital twin approach allows precise determination of rod curvature without requiring physical trial-and-error bending during surgery

Inventive Principle:
Principle #26Copying

2Adaptability or versatility

If freehand rod bending is performed during surgery, then the rod can be adapted to patient anatomy, but the difficulty of operation increases

Engineering Contradiction:
Improvepatient-specific rod customizationVSAvoidrod bending difficulty
Core Design Contradiction:
Adaptability or versatilityVSEase of operation

Solution Approach 1:

The patent replaces the manual mechanical skill of freehand rod bending with an automated computational system. Software algorithms automatically calculate the optimal rod curvature based on patient anatomy and screw positions, eliminating the need for surgeon expertise in manual bending techniques while maintaining high adaptability to individual patient needs

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

Solution Approach 2:

The patent introduces a computational model and virtual planning software as an intermediary between patient anatomy and the physical rod. This intermediary automatically translates anatomical data into precise rod bending parameters, removing the complexity of manual judgment and skill required for freehand bending

Inventive Principle:
Principle #24Intermediary (Mediator)

Data Source

PatentEP4489672B1Method for calculating the shape of a rod of a pedicle screw system for spinal fusion
Publication Date: 2026.04.08 MEDACTA INT SA
  • EP4489672B1 patent drawingFigure 1
  • EP4489672B1 patent drawingFigure 1
  • EP4489672B1 patent drawingFigure 2

AI summary

Method for calculating the shape of a rod of a pedicle screw system comprising: a) acquiring (10) at least one bidimensional image of a spine; b) acquiring (20) a tridimensional image of a spine; c) obtaining (30; 40, 50) a tridimensional model of the spine; d) performing (60) a sagittal balance analysis to calculate spino pelvic parameters and comparing them with predetermined values; e) applying (70) corrections to the tridimensional model; f) calculating (80) corrected spino pelvic parameters on the tridimensional model of the spine corrected and checking if they are within the predetermined range values, g) in negative case, repeating steps e) – f); i) in positive case, obtaining (90) a tridimensional corrected model of the spine based on such tridimensional simulated corrections including a plurality of virtual screw; j) calculating (100) the shape of the rod as mathematical function which approximates the curve passing through the virtual screw.