Disposable Intramedullary Device with Antibiotic Polymer Coating
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Solution Overview
Problem
Existing intramedullary devices for treating limb infections face issues with adhesion and stability during insertion, potential damage from locking screws, and uneven distribution of antibiotic layers, leading to reduced mechanical resistance and increased surgical time and costs.
Innovation Solution
A disposable intramedullary device with a solid core of variable cross-section, coated with a polymer and antibiotic layer, where the anchoring regions have no coating to maintain strength and the outer diameter matches the intramedullary channel, preventing sliding and ensuring homogeneous antibiotic distribution.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a disposable intramedullary device with a cover is used to treat limb infections, then antibiotic treatment capability is improved, but the device may slide or deteriorate during insertion due to insufficient adhesion
Solution Approach 1:
The patent applies local quality by creating different surface characteristics at different locations of the intramedullary nail. The anchoring regions have a roughened surface texture that provides enhanced adhesion for the polymer-antibiotic layer, while other regions maintain smooth surfaces. This localized variation in surface quality ensures the polymer layer adheres firmly at critical anchoring points without compromising the overall device function.
2Reliability
If the cover encloses the whole length of the metal core, then antibiotic distribution is improved, but the nail has reduced resistance to torsional and bending stresses in anchoring regions
Solution Approach 1:
The patent segments the intramedullary nail into distinct functional zones: anchoring regions with roughened surfaces that provide mechanical interlocking and enhanced strength, and intermediate regions with smooth surfaces covered by the polymer-antibiotic layer. This segmentation allows the device to simultaneously achieve good antibiotic distribution in covered regions while maintaining high mechanical resistance in exposed anchoring regions.
3Force
If locking screws are used for anchoring the device to the bone, then fixation capability is improved, but the screws may damage the cover
Solution Approach 1:
The roughened surface texture is specifically applied at anchoring regions where locking screws will be inserted. This localized surface modification provides enhanced grip and fixation capability at these critical points while the smooth covered regions remain protected from screw damage. The differential surface quality ensures screws engage firmly with the bone without compromising the polymer-antibiotic layer integrity.
4Strength
If a hollow metal intramedullary nail is used, then mechanical strength is improved, but the device is not prepared to cope with eventual infection in the implantation zone
Solution Approach 1:
The patent creates a composite structure by coating the hollow metal intramedullary nail with a polymer-antibiotic layer. The metal core provides the necessary mechanical strength and structural integrity, while the polymer coating infused with antibiotic agents provides infection prevention and treatment capabilities. This composite construction allows the device to simultaneously achieve both mechanical strength and antimicrobial protection.
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 solution provides enhanced mechanical resistance, reduces the risk of material dragging, and ensures uniform antibiotic distribution, minimizing surgical time and costs while maintaining structural integrity and preventing damage to the antibiotic layer.
Implementation Method 1
which is obtained through a die and the mixture of polymer and antibiotic drains in those regions of the solid core other than the anchoring regions (5)
Data Source
AI summary
A disposable intramedullary device for temporary use for treatment of limb infections comprising a solid core of variable cross-section, including a distal portion, a middle portion and a proximal portion, said proximal portion and distal portion including anchoring regions consisting of through-holes being passed through by bone anchoring means. Outside said anchoring regions, said solid core is coated with a polymer layer which also includes antibiotic, the outer diameter of the solid core and polymer layer assembly being equivalent to that of an intramedullary channel, and the outer diameter of said solid core in said anchoring regions being equivalent to that of said intramedullary channel.