Self-Actuating Growing Rods for Constant Distraction Force
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Solution Overview
Problem
Existing medical implant systems for skeletal deformities require invasive surgical interventions to adjust for natural growth, such as elongation of the spine, and are either fluid-based with leakage risks or lack a consistent distraction force.
Innovation Solution
A self-actuating growing rod system with pre-compressed compression springs and magnetic or mechanical biasing mechanisms that maintain a constant distraction force through telescopic growth, using magnetic field-based actuation to adjust the spring compression without invasive procedures.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If manual correction and affixation of medical implants is performed by a surgeon, then the corrected bony anatomy is supported initially, but repetitive invasive surgical interventions are required whenever the patient undergoes natural growth
Solution Approach 1:
The growing rod system is designed to automatically adjust and extend itself during natural growth without requiring surgical intervention. The system includes a growth rod component that telescopes out of an intermediate rod component in response to natural growth, and a spring actuation mechanism that automatically applies distraction force, making the system self-regulating and eliminating the need for repetitive manual corrections by the surgeon.
Solution Approach 2:
The system transitions from a static implant to a dynamic one that automatically adapts to natural growth. The growth rod component can telescope out of the intermediate rod component, and the spring actuation mechanism can dynamically adjust the distraction force, allowing the system to respond automatically to changes in the patient's growth without requiring manual intervention.
2Adaptability or versatility
If fluid-based systems are used to provide natural growth-friendly support, then the system is growth-friendly without surgical intervention, but fluid leakage risks increase and the system weight and cost increase
Solution Approach 1:
The invention extracts the fluid-based mechanism from the system and replaces it with a solid mechanical spring actuation mechanism. The spring-based system eliminates the need for fluids, seals, and associated leakage risks, while maintaining the ability to provide automatic distraction force during natural growth. This extraction of the problematic fluid component directly addresses the reliability issue while preserving the growth-friendly adaptability.
3Force
If the surgeon decides how much the system is to be distracted post implantation, then initial support is provided, but human error occurs and the system is not naturally growth-driven
Solution Approach 1:
The system eliminates dependence on surgeon decision-making by implementing a self-regulating mechanism. The spring actuation mechanism automatically adjusts the distraction force in response to natural growth, and the growth rod component automatically telescopes to match the patient's growth pattern. This self-service approach removes human error from the equation while ensuring the distraction force is always appropriately calibrated to the patient's current growth state.
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 provides a safe, economical, and growth-friendly solution that maintains active distraction force without repetitive surgeries, ensuring continuous support for corrected bony anatomy during natural growth.
Implementation Method 1
at least one magnetic field-based spring actuation mechanism
Implementation Method 2
causing the relaxed compression spring(s) to regain compression by means of at least one mechanism selected from the group consisting of said magnetic field-based spring actuation mechanism
Data Source
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AI summary
A constant distraction force driven self-actuating growing rod system is provided for implantation on a corrected bony anatomy. The system includes components selected from the group consisting of at least one static rod, intermediate rod, or growth rod component; at least one compression spring component; at least one magnetic field-based spring actuation mechanism; at least one mechanical biasing mechanism, at least one casing, at least one guide rod and at least one spring actuator mechanism to apply an active distraction force; at least one magnetic field-based spring actuation mechanism and at least one dynamic sealing plug. During natural growth of the corrected bony anatomy, the growth rod component telescopes out of the intermediate rod component, creating a distraction force deficit that is corrected by causing the compression spring component to get compressed by the magnetic field-based spring actuation mechanism or the mechanical biasing mechanism, thereby maintaining an active distraction force.