Beta-Titanium Temporary Lead Coil for High-Strain Electrode Stability
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Solution Overview
Problem
Existing medical electrical leads for sacral nerve stimulation face challenges in maintaining electrode fixation during high strain levels, leading to potential migration or dislodgement of the distal end electrode during the trial period, and require complex fixation components for stability.
Innovation Solution
A temporary medical electrical lead with a single conductor coil that can be strained up to 400% without transmitting a force greater than 0.4 N, utilizing a beta-titanium alloy coil with a 1x19 configuration, which absorbs strain without dislodging the electrode, and a system including an introducer needle, stylet, and grip tool for secure implantation and removal.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a temporary medical electrical lead is subjected to high strain levels during implantation and patient movement, then the lead can accommodate body movement and positioning, but the electrode may migrate or dislodge from the sacral nerve stimulation site
Solution Approach 1:
The patent applies beforehand cushioning by incorporating a strain relief coil constructed from beta-titanium alloy that absorbs mechanical strain before it reaches the electrode. The coil is designed with specific mechanical properties (spring constant k ≤ 0.005 N/mm) to cushion and dissipate forces generated during implantation and patient movement, preventing these forces from dislodging the electrode at the sacral nerve stimulation site.
2Reliability
If fixation components are added to prevent electrode migration, then electrode stability is improved, but the device complexity and difficulty of implantation increase
Solution Approach 1:
The patent applies the taking out principle by removing complex fixation components from the lead design. Instead of adding anchors, screws, or other fixation mechanisms, the invention extracts the fixation function and replaces it with a passive strain relief coil that relies on its mechanical properties (low spring constant, high elasticity) to prevent electrode migration. This simplifies the overall device while maintaining reliability.
3Strength
If the lead coil is made more rigid to maintain structural integrity, then lead strength is improved, but the lead cannot accommodate high strain levels during implantation and patient movement
Solution Approach 1:
The patent applies parameter changes by selecting beta-titanium alloy with specific mechanical properties and designing the coil with a spring constant k ≤ 0.005 N/mm. This parameter optimization allows the lead to achieve both strength and flexibility: the beta-titanium alloy provides sufficient structural integrity while the low spring constant enables the coil to accommodate high strain levels (≥300%) during implantation and patient movement without transmitting excessive force to the electrode.
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 ensures stable electrode placement during high strain conditions, reduces lead migration, and facilitates easy removal without fixation components, enhancing the effectiveness and longevity of the lead.
Implementation Method 1
The single conductor coil may be strained at least 300% or 400% and may not transmit a force greater than 0.4 N (0.1 Ibf)
Data Source
Figure 1
Figure 2A
Figure 2B~2C
AI summary
A temporary medical electrical lead includes a connector pin and a single conductor coil. The coil being close-wound and having no turns of the coil distal portion being mechanically coupled together. The coil distal portion translates a force of no greater than 0.4 N (0.1 Ibf) when strained 400%.