Orthopaedic Rod Bender Template Curvature Replication
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Solution Overview
Problem
Existing orthopaedic rod benders require significant manual force and generate compressional, tensional, and torsional stresses during bending, making it difficult to achieve precise curvature matching with implanted spinal screws, and often necessitate multiple adjustments and rod reinsertions, which can cause stress in the rod and complicate spinal deformity correction.
Innovation Solution
An orthopaedic rod bender system that applies only tensional forces during bending by using a template rod made of work-hardening material, which is manually bent to match the curvature of implanted screws, and then used to impart a similar curvature to a second rod, minimizing stress and allowing for reduced manual effort and precise curvature replication.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If manual force is applied to bend the rod using known rod benders, then curvature can be imparted to the rod, but considerable physical force is required and multiple adjustments are needed
Solution Approach 1:
A pre-bent template rod is created beforehand to define the desired curvature. The template rod is manually bent to match the curvature defined by implanted screw heads, then used as a guide to impart the same curvature to the final rod, eliminating the need for repeated manual bending adjustments during surgery
Solution Approach 2:
The curvature defined by the implanted screw heads is copied onto a template rod, which then serves as a physical model to replicate the exact same curvature on the final rod. This copying process ensures precise curvature matching without requiring the surgeon to repeatedly apply manual force and make adjustments
2Manufacturing precision
If the rod is repeatedly removed and re-inserted for bending adjustments, then curvature can be adjusted, but the process time increases and stress is generated in the rod
Solution Approach 1:
The template rod is prepared in advance with the correct curvature, allowing the final rod to be bent in a single operation by following the template guide, eliminating the need for repeated removal and reinsertion cycles that consume surgical time
3Shape
If compressional, tensional and torsional forces are applied by the rod bender, then the rod can be bent, but stress is generated in the rod which may affect its durability
Solution Approach 1:
The bending process is designed to apply forces locally at specific contact points between the rod and the template rod, rather than applying distributed compressional and torsional forces. This localized bending minimizes stress generation in the rod while achieving the desired curvature
Solution Approach 2:
The rod bending process is transformed from applying complex multi-axial forces (compression, tension, torsion) to applying simple uniaxial bending forces by following the template rod geometry. This parameter change in the force application method reduces stress in the rod
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 system reduces stress on the orthopaedic rod during bending, enabling longer durability and easier curvature matching with implanted screws, while minimizing manual force and repetitive adjustments, thus enhancing the efficiency and precision of spinal deformity correction.
Implementation Method 1
a template rod (5) made of work-hardening material, which is manually bent to define a curvature
Implementation Method 2
manually bent to define a curvature matching a curvature defined by a plurality of implanted spinal screw heads
Data Source
Figure 1A~1C
Figure 2A
Figure 2B
AI summary
The present invention concerns an orthopaedic rod bender including: a rod receiving zone configured to receive a first rod having a predefined curvature and a second rod to which a curvature is to be imparted; a first support and a second support for contacting the first rod, the first and the second 9B supports being located on a first side of the rod receiving zone opposite the first side; and a mobile head located on a second side of the rod receiving zone; the mobile head being configured to be displaced towards the first side and in the rod receiving zone to contact the second rod and to apply a force to the second rod to push the second rod towards the first rod to impart a curvature to the second rod.