Dual Pectus Bar Stabilization for Chest Deformity Correction

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Solution Overview

Problem

The Nuss procedure for correcting pectus excavatum faces challenges in stabilizing the pectus bar against restoring forces and preventing displacement, which can lead to correction errors and organ damage due to variations in restoring forces and external physical forces.

Innovation Solution

A medical apparatus comprising two curved pectus bars with elastic restoring force, brackets, and coupling units that include slides and bolts to securely fix the pectus bars to the ribs, allowing for flexibility and stability during correction, with bridges maintaining distance between the bars to prevent upward or downward displacement.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If a single pectus bar is used to correct pectus excavatum, then the surgical procedure is simpler and operation time is reduced, but the pectus bar becomes unstable against restoring forces and may displace from correction range

Engineering Contradiction:

Improveoperation timeVSAvoidstability of pectus bar

Core Design Contradiction:

ProductivityVSReliability

Solution Approach 1:

The correction apparatus is divided into multiple independent pectus bars (typically two bars: upper and lower) that work together to correct the deformity. Each bar is independently supported by ribs and coupling units, distributing the correcting force and improving overall stability while maintaining surgical efficiency

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The patent introduces vertical spacing between upper and lower pectus bars, adding a vertical dimension to the correction system. This multi-level arrangement creates a more stable structural configuration that better resists restoring forces compared to a single-bar approach

Inventive Principle:

Principle #17Another dimension (Dimensionality change)

2Stability of the object's composition

If pectus bars are firmly fixed to prevent displacement, then correction stability is improved, but flexibility and resilience of the chest wall are reduced

Engineering Contradiction:

Improvecorrection stabilityVSAvoidflexibility of chest wall

Core Design Contradiction:

Stability of the object's compositionVSAdaptability or versatility

Solution Approach 1:

The coupling units incorporate movable connections between pectus bars and ribs, allowing dynamic adjustment and movement. This enables the chest wall to maintain flexibility and resilience while the pectus bars provide stable correction, resolving the contradiction between firm fixation and physiological flexibility

Inventive Principle:

Principle #15Dynamics

Solution Approach 2:

The patent uses elastic materials for the pectus bars that can change their mechanical properties. The bars have controlled elasticity that allows them to flex under physiological loads while maintaining corrective force, adapting to varying restoring forces during the correction process

Inventive Principle:

Principle #35Parameter changes

3Force

If pectus bars are made with high elastic restoring force to counteract strong restoring forces early in correction, then correction effectiveness is improved, but displacement and correction errors increase due to excessive force variations

Engineering Contradiction:

Improveelastic restoring force of pectus barVSAvoidcorrection accuracy

Core Design Contradiction:

ForceVSManufacturing precision

Solution Approach 1:

The correction force is distributed across multiple pectus bars rather than concentrated in a single bar. This segmentation of force application reduces the elastic restoring force required per bar, preventing excessive force variations that could cause displacement while maintaining overall correction effectiveness

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The patent employs multiple pectus bars positioned at different locations (upper and lower) that work together to balance and counteract the restoring forces. This distributed counterbalancing approach provides more stable and controlled correction forces compared to a single high-force bar

Inventive Principle:

Principle #8Anti-weight (Counterweight)

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 apparatus provides stability and flexibility to maintain the corrected chest shape by dispersing restoring forces and preventing displacement of the pectus bars, ensuring accurate correction and minimizing risk to internal organs.

Implementation Method 1

two curved pectus bars with elastic restoring force

Methodology Applied

Scientific EffectElasticity: Elasticity

Data Source

PatentUS9872708B2Medical device for pectus excavatum deformity correction surgery

Publication Date: 2018.01.23 PARK HYUNG JOO

AI summary

A pectus excavatum correction apparatus includes two pectus bars each made of a stick plate. Each bracket of the apparatus has a plate shape with a length-direction bent part. The first side of the bent part is hooked onto an upper or lower part of a rib and a second side of the bent part faces an outer surface of the pectus bar. Each of a first and second bridge has through-holes provided in two length-direction ends of the bridge. Each coupling unit includes a supporting part provided between the rib and the pectus bar, a slide protruding from an outer surface of the supporting part, and a second coupling part coupled to the first coupling part to press and fix the pectus bar, the bracket, and the bridge. The second distance is greater or less than the first distance within a preset range.