Twisted Pair Conductors for EMI Noise Attenuation in Implantable Leads
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Solution Overview
Problem
Implantable medical leads and lead extensions are susceptible to electromagnetic interference (EMI) noise, which can hinder the ability of implantable medical devices to effectively sense physiological signals and deliver stimulation therapy.
Innovation Solution
Incorporating at least one twisted pair of electrical conductors within the implantable medical lead, where the twisted pair connects proximal and distal electrodes, to attenuate EMI noise through field cancellation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If traditional conductors are used in implantable medical leads, then the lead structure is simple and easy to manufacture, but the lead is susceptible to electromagnetic interference (EMI) noise that hinders sensing and stimulation functions
Solution Approach 1:
The patent applies the twisted pair configuration to convert the harmful EMI noise into a beneficial shielding effect. By twisting two conductors together, the electromagnetic interference induced on each conductor is equal in magnitude but opposite in polarity, causing the noise to cancel out. This transforms the previously harmful EMI into a useful noise-cancellation mechanism that protects the sensing and stimulation functions while maintaining simple lead construction.
2Length of moving object
If lead extensions are used to extend the lead length, then the lead can reach the implantable medical device, but the extended lead is exposed to more EMI noise sources
Solution Approach 1:
The twisted pair configuration in lead extensions converts the increased EMI exposure from extended length into a beneficial shielding effect. As the lead extension travels through the body, it encounters more EMI sources, but the twisted pair structure ensures that noise induced on both conductors cancels out, allowing the lead to achieve necessary length without proportionally increasing noise susceptibility.
3Object-affected harmful factors
If twisted pair conductors are used to reduce EMI noise, then EMI attenuation is improved, but the lead construction becomes more complex
Solution Approach 1:
The patent segments the lead construction into twisted pair bundles, where conductors are grouped in pairs and twisted together. This segmentation approach allows the complex EMI shielding function to be achieved through simple, repetitive twisting of conductor pairs rather than requiring complex overall lead architecture. Each twisted pair independently provides noise cancellation, making the complexity modular and manageable.
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 use of twisted pairs effectively reduces EMI noise, improving the ability of implantable medical devices to sense physiological signals and deliver stimulation therapy by minimizing interference.
Implementation Method 1
EMI noise that reaches the twisted pair is attenuated at least by virtue of field cancellation produced by the twisted pair
Data Source
AI summary
Implantable medical systems that include an implantable medical lead coupled to an implantable medical device for purposes of electrical stimulation therapy and/or sensing of physiological signals includes at least one twisted pair of conductors within the implantable medical lead. The twisted pair corresponds to a stimulation or sensing channel of the implantable medical device. The twisted pair provides attenuation of electromagnetic interference noise that is present at the lead or lead extension. The twisted pair may be present in a lumen of the implantable medical lead or encapsulated by the lead body. The twisted pair, along with any other conductors of the lead, may be of a linear configuration or may be coiled.