Antibiotic Intramedullary Nail with Removable Cement Segment

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Solution Overview

Problem

Conventional antibiotic intramedullary nails face issues with bacterial adherence and infection due to their design, leading to potential complications during removal, as the cement coating may break off and be left in the bone, and they are not effective against both gram-positive and gram-negative bacterial infections.

Innovation Solution

The development of an ultramedullary nail with a smooth transition from the metal to the antibiotic cement portion, allowing for easy insertion and removal, and the ability to customize antibiotics, which can be used to treat acute or chronic infections, fractures at risk for infection, and nonunions, while providing prophylactic antibiotics.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If the cement coating is applied to deliver antibiotics locally, then the antibiotic delivery effectiveness is improved, but the cement may break off during removal and be left in the medullary cavity

Engineering Contradiction:

Improveantibiotic delivery effectivenessVSAvoidcement fragmentation and retention in bone

Core Design Contradiction:

ReliabilityVSObject-generated harmful factors

Solution Approach 1:

The intramedullary nail is divided into distinct sections: a metal portion for structural integrity and a cement portion for antibiotic delivery. The cement portion is designed as a separate, removable segment that can be extracted without damaging the metal nail, allowing complete removal of the cement coating to prevent retention in the medullary cavity while maintaining effective antibiotic delivery during the treatment period.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The nail design incorporates a dynamic feature where the cement coating is applied only to a specific portion of the nail that can be selectively removed. This allows the nail to transition from a static structure to a dynamic system where the cement portion can be detached and removed after serving its antibiotic delivery function, preventing cement fragmentation issues during removal.

Inventive Principle:

Principle #15Dynamics

2Quantity of substance

If the cement-covered portion has a larger cross-sectional area, then the antibiotic coating is more substantial, but the removal becomes more difficult and cement may be left in the bone

Engineering Contradiction:

Improveantibiotic cement amountVSAvoidremoval ease

Core Design Contradiction:

Quantity of substanceVSEase of operation

Solution Approach 1:

The nail is segmented into a metal portion and a cement portion with distinct cross-sectional profiles. The cement portion, while having sufficient cross-sectional area for substantial antibiotic coating, is designed as a separate removable segment. This segmentation allows the cement portion to be completely extracted from the metal nail and removed from the bone, preventing cement retention despite having adequate antibiotic loading capacity.

Inventive Principle:

Principle #1Segmentation

3Reliability

If conventional antibiotic IMNs are used, then they provide stability and local antibiotic delivery, but bacteria can adhere to the IMN and become a source of continued infection

Engineering Contradiction:

Improvefracture stability and antibiotic deliveryVSAvoidbacterial adherence and continued infection

Core Design Contradiction:

ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The harmful aspect of bacterial adherence is addressed by designing the cement portion as a removable component that can be completely extracted from the bone after serving its antibiotic delivery function. This extraction removes the potential surface for bacterial adherence and eliminates the risk of continued infection, while the metal portion maintains fracture stability throughout the treatment period.

Inventive Principle:

Principle #2Taking out (Extraction)

Solution Approach 2:

The cement portion is designed as a disposable, removable component that is removed after a predetermined period. This short-living design prevents long-term bacterial adherence and infection risk, while the metal nail portion serves as the permanent, stable structure. The removable cement portion can be completely extracted without leaving debris that could serve as a infection source.

Inventive Principle:

Principle #27Cheap short-living objects (Disposable)

4Object-affected harmful factors

If the cement coating is removed completely, then bacterial adherence is reduced, but the antibiotic delivery function is compromised

Engineering Contradiction:

Improvebacterial adherence reductionVSAvoidantibiotic delivery function

Core Design Contradiction:

Object-affected harmful factorsVSReliability

Solution Approach 1:

The cement portion is pre-applied to the metal nail before insertion into the bone, ensuring that antibiotic delivery is established before the nail is placed in the patient. This preliminary action allows the cement portion to serve its antibiotic delivery function during the critical treatment period, after which it can be completely removed to prevent bacterial adherence, thus resolving the contradiction between maintaining delivery function and preventing infection.

Inventive Principle:

Principle #10Preliminary action

Data Source

PatentUS20240225703A1Antibiotic intramedulary nail apparatus, system, and method

Publication Date: 2024.07.11 HOEGLER JOSEPH

AI summary

An apparatus that can include a threaded handle and a removable sleeve for inserting concrete.