Removal Forces of a Helical Microwire Structure Electrode

Area of Science:

• Biomedical Engineering
• Materials Science
• Neurosurgery

Background:

• Medical device explantation can cause significant tissue trauma and device fracture due to removal forces.
• The device's interaction with surrounding tissue is a key factor influencing removal forces.
• Helical and linear electrode structures were investigated to study atraumatic removal.

Purpose of the Study:

• To test the hypothesis that a device's form factor impacts removal force.
• To compare the removal forces of helical versus linear electrode structures.
• To evaluate the safety and efficacy of helical designs for medical device removal.

Main Methods:

• Fabrication of ductile linear and helical microwire electrodes using Gold (Au) and Platinum-Iridium (Pt-Ir).
• Measurement of removal forces using synthetic gel models.
• Assessment of removal forces in rodent and porcine models following chronic implantation (1 year).

Main Results:

• Helical devices demonstrated significantly lower maximal removal forces than linear devices in both synthetic and rodent models.
• Chronic implantation showed helical devices had maximal removal forces under 7.30 N.
• The Platinum-Iridium helical device exhibited a safety factor of 4.50, with a tensile failure force of 32.90 ± 2.09 N.

Conclusions:

• An open-core helical structure design reduces removal forces for medical devices.
• This helical design promotes atraumatic removal, minimizing tissue trauma and device damage.
• The findings support the use of helical structures for safer and more efficient medical device explantation.