Embolization Coil With Waveform Stretch-Resistant Member
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Solution Overview
Problem
The challenge in manufacturing indwelling devices for embolization is that the size of the coil portion changes during sterilization when a stretch-resistant member with a small spring constant is disposed, making it difficult to maintain an appropriate size.
Innovation Solution
The indwelling device incorporates a coil portion with a lumen and a stretch-resistant member having a specific waveform and spring constant, where the wave height is larger than the inner diameter of the coil portion, and the wavelength is between 280 µm and 400 µm, to minimize size changes during sterilization.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a stretch-resistant member with a small spring constant is disposed inside the coil portion, then the coil portion can be prevented from stretching unlimitedly, but the size of the coil portion changes during sterilization
Solution Approach 1:
The patent specifies precise parameter ranges for the stretch-resistant member: spring constant of 0.01 to 0.5 N/mm, wave height of 35-70 μm, and wavelength of 280-400 μm. By optimizing these parameters, the member provides sufficient stretch resistance while maintaining coil size stability during sterilization
Solution Approach 2:
The stretch-resistant member is designed with a waveform structure that allows dynamic deformation. The wave height and wavelength create a flexible structure that can accommodate sterilization-induced dimensional changes while preventing excessive stretching during use
2Manufacturing precision
If the wave height of the stretch-resistant member is increased, then the suppression of coil portion size change is improved, but the member may become too rigid
Solution Approach 1:
The patent defines an optimal wave height range of 35-70 μm that balances rigidity and flexibility. This parameter range provides sufficient structural support to prevent coil size change during sterilization while maintaining the flexibility needed for safe deployment
Solution Approach 2:
The stretch-resistant member is made from materials with specific mechanical properties that complement the waveform geometry. The combination of material selection and wave height optimization creates a structure that is rigid enough for size stability but flexible for deployment
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
This configuration effectively suppresses changes in the coil portion's size during sterilization, allowing for the production of indwelling devices with consistent dimensions suitable for embolization, ensuring the coil portion remains appropriately sized for its intended application.
Implementation Method 1
a spring constant of the coil portion is 1.0 N/mm or less, the stretch-resistant member has a waveform, and a wave height, which is a distance between peaks on an inner side of the waveform of the stretch-resistant member, is 35 μm or larger and smaller than an inner diameter of the coil portion
Data Source
Figure 1~2
Figure 3
AI summary
In an indwelling device for embolization comprising a coil portion (11) having a proximal side and a distal side and having a lumen extending in a longitudinal direction, and a stretch-resistant member (20) disposed in the lumen, a spring constant of the coil portion (11) is 1.0 N/mm or less, the stretch-resistant member (20) has a waveform, and a wave height, which is a distance between peaks on an inner side of the waveform of the stretch-resistant member (20), is 35 µm or larger and smaller than an inner diameter of the coil portion (11), in order to provide the indwelling device for embolization that suppresses changes in dimension of the coil portion (11) during sterilization.