Vagus Nerve StimulationFinite Element Model

Kris CarlsonArle Lab Med Device Consulting Group

BIDMC/Harvard Medical SchoolNovember 2015

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The Vagus Nerve• Stimulator is implanted near the larynx for seizure control

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Finite Element Model Features

– Geometry built with COMSOL CAD, not 3rd party CAD program• Meshes and solves faster than with 3rd party CAD• Can do longer time dependent studies• Can do broader parameter sweeps

– Over a dozen parameterized variables are easily changed

– Thin layers and contact impedance solved programmatically

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Finite Element Model Vagus nerve embedded in ambient medium

Finite element analysis software: COMSOL Multiphysics

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Finite Element Model Closeup of helical cathode (top) and anode (bottom)

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Finite Element Model Mesh with mesh quality legend

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Finite Element Model Mesh – View into center of nerve

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Finite Element Model Electric potential – mid-cathode – 2.25 mA

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Finite Element Model Multislice plot of electric potential

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Finite Element Model Contour plot of electric potential on fascicles

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Finite Element Model Electric potential on recurrent laryngeal fascicle

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Finite Element Model Slice plots of electric potential in fascicles at cathode and anode

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Finite Element Model Electric potential in fascicles between cathode and anode

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Finite Element Model Slice plots of electric potential in fascicles at cathode

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Finite Element Model Electric potential along axon in superficial epineurium (left) and recurrent laryngeal fascicle (right)