Spinal Rod Connector with Dual-Stage Clamp Fixation

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Solution Overview

Problem

Existing rod connectors for spinal rods lack a secure and adjustable mechanism for cross-connection, particularly in orthopedic operations where precise alignment and fixation are crucial, and existing solutions either provide insufficient stability or are cumbersome to use.

Innovation Solution

A rod connector with two partial clamps that securely fasten to spinal rods using a spring mechanism for initial adjustment and a locking device for final fixation, featuring a crossbar with adjustable and rotatable legs for precise alignment, and a dual-function clamp with a spring bar for secure attachment and adjustment.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a clamping jaw is pressed against the rod with the aid of a screw (US Pat. No. 7,029,474 B2), then the rod connector provides stable fixation, but the device complexity increases and the ease of operation decreases

Engineering Contradiction:
Improvefixation stabilityVSAvoidconnector structure
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The rod connector is divided into two separate clamps that can be independently attached to each rod, rather than a single complex connector. Each clamp is a simplified component that can be independently positioned and secured, reducing overall device complexity while maintaining fixation stability.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The clamps are designed with dynamic adjustment capabilities, allowing the surgeon to adjust the position and clamping force during the procedure. This dynamic design replaces rigid screw mechanisms with more flexible adjustment systems that are easier to operate while providing reliable fixation.

Inventive Principle:
Principle #15Dynamics

2Ease of operation

If an expandable clamp is snapped onto the rod (US Pat. No. 7,066,938B2), then the ease of operation improves, but the reliability of fixation decreases

Engineering Contradiction:
Improveclamp installationVSAvoidfixation stability
Core Design Contradiction:
Ease of operationVSReliability

Solution Approach 1:

The design merges the ease of snap-fit installation with the reliability of secure fixation by combining an expandable clamp mechanism with a locking feature. The clamp can be quickly snapped onto the rod like an expandable clamp, but then locked into place to provide stable, reliable fixation that doesn't compromise structural integrity.

Inventive Principle:
Principle #5Merging (Combining)

3Ease of operation

If the spring force is designed to be low for manual snapping, then the ease of operation improves, but the holding force decreases

Engineering Contradiction:
Improvemanual installationVSAvoidholding force
Core Design Contradiction:
Ease of operationVSForce

Solution Approach 1:

The spring mechanism is designed to provide preliminary holding force that is sufficient for manual installation and initial positioning, but a separate locking mechanism is then engaged to provide the final secure fixation. This two-stage approach allows low spring force for easy installation while ensuring high holding force for stable fixation.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The spring acts as an intermediary between the manual installation process and the final locking mechanism. It provides enough force to hold the clamp in place during positioning, but the locking mechanism then takes over to provide the primary holding force, allowing the spring to remain weak for ease of operation.

Inventive Principle:
Principle #24Intermediary (Mediator)

4Manufacturing precision

If the crossbar is rigid for fixed orientation, then the manufacturing precision improves, but the adaptability decreases

Engineering Contradiction:
Improveclamp alignmentVSAvoidrod position adjustment
Core Design Contradiction:
Manufacturing precisionVSAdaptability or versatility

Solution Approach 1:

The crossbar is designed with adjustable or movable features that allow it to adapt to different rod positions and orientations during surgery. This dynamic design enables the crossbar to maintain precise alignment of clamps while accommodating variations in rod placement, combining manufacturing precision with surgical adaptability.

Inventive Principle:
Principle #15Dynamics

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

Enables secure, adjustable, and precise cross-connection of spinal rods, allowing for easy initial placement and final locking without tools, ensuring stability and flexibility during orthopedic procedures.

Implementation Method 1

spring means for the clamp. In other words, the clamp is designed to be resilient so that it can be snapped onto the spinal rod or removed from it again

Methodology Applied
Scientific EffectElasticity: Elasticity

Implementation Method 2

If the fixing device is actuated, it generates an additional holding force, which the clamp exerts on the spinal rod, which supplements or replaces the spring force. The holding force is so great that the clamp is firmly fixed to the spinal rod in the assembled state

Methodology Applied
Scientific EffectFriction: Friction

Data Source

PatentEP2480149B1Rod connector for cross-connecting of two spinal rods
Publication Date: 2017.05.03 KRAUS KILIAN
  • EP2480149B1 patent drawingFigure 1
  • EP2480149B1 patent drawingFigure 2
  • EP2480149B1 patent drawingFigure 3

AI summary

The invention relates to a rod connector (2) for transversely connecting two vertebral column rods (4a, b), comprising: two clamps, each partially enclosing and fastening a vertebral column rod (4a, b) in an installed state, a transverse stay (11) fixing the location of the clamps (14) relative to each other, a spring device (47) for the clamp (14), the spring force (F) thereof being low enough, such that the clamp (14) can be manually snapped onto the vertebral column rod (4a, b), can be slid onto same in the installed state, and can be released from same, an attaching device (53) for the clamp (14), independent of the spring device (47), the retaining force (H) thereof being high enough, such that the clamp (14) is solidly attached on the vertebral column rod (4a, b) in the installed state.