3D Spinal Correction Planning for Deformation-Aware Rod Contours
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Solution Overview
Problem
Existing spinal rods used for correcting spinal deformities, such as adolescent idiopathic scoliosis, deform due to in vivo impact forces, complicating the treatment process.
Innovation Solution
A method and system for planning patient-specific spinal correction surgery by transforming 2D pre-operative spinal images to 3D representations, applying mathematical formulas to determine a rod design that accounts for deformation, and bending rods during surgery to achieve a thoracic kyphosis goal using biocompatible materials.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If standard spinal rods are used for correcting spinal deformities, then the surgery can be performed with conventional implants, but the rods deform due to in vivo impact forces, complicating the treatment process
Solution Approach 1:
The rod contour is pre-calculated and pre-bent to account for the expected deformation that will occur after implantation. The planning system computes the required bend-out amount based on patient-specific deformity characteristics and rod material properties, so that when the rod deforms in vivo, it achieves the desired spinal alignment rather than deviating from it
Solution Approach 2:
The rod is intentionally bent beyond the target correction angle during surgery (excessive action), with the excess bend compensating for the anticipated deformation. This ensures that after the rod deforms under physiological loads, the spinal correction remains at or near the desired target angle
2Manufacturing precision
If rod contour is designed without accounting for deformation, then the initial spinal alignment can be achieved, but the rod deforms under in vivo forces, leading to loss of correction
Solution Approach 1:
The planning system performs preliminary calculations to determine the exact bend-out contour required before surgery. This pre-planning incorporates patient-specific anatomical measurements, deformity characteristics, and rod material properties to compute the optimal pre-bent contour that will result in the desired post-deformation alignment
Solution Approach 2:
The system uses iterative computational methods to refine the rod contour design. The planning software simulates the expected deformation and adjusts the pre-bent contour accordingly, creating a feedback loop between predicted deformation and required initial configuration to achieve accurate final alignment
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
The solution allows for precise correction of spinal deformities by designing rods that account for in vivo deformation, ensuring effective treatment outcomes.
Implementation Method 1
transforming the 2D pre-operative spinal image to a three-dimensional (3D), pre-operative spinal image representation. The transforming may include performing segmentation of spine elements in the 2D pre-operative spinal image, and applying a mathematical formula based on the thoracic Cobb angle and the thoracic kyphosis to the spine elements
Implementation Method 2
These spinal rods, however, can deform based on in vivo impact forces. The spinal rod curvature can be a key factor in the treatment of a spinal deformity
Implementation Method 3
These spinal rods, however, can deform based on in vivo impact forces
Data Source
AI summary
Systems and methods are provided to plan a spinal correction surgery. The method includes measuring parameters of a spine in a two-dimensional (2D) spinal image including a thoracic Cobb angle and a thoracic kyphosis (TK) and transforming the 2D image to a three-dimensional (3D), spinal image representation. The transforming includes performing segmentation of spine elements in the 2D image, and applying a formula based on the thoracic Cobb angle and the TK to the spine elements. The method includes identifying a TK goal having a post-operative TK value to selected spine elements, transforming a gap of the spine elements representative of a difference between the pre-operative TK in 3D spinal image representation and the TK goal to create a 3D post-operative spinal image representation, and determining a first rod design based on the 3D post-operative spinal image representation to achieve the post-operative TK value in the spine elements.