Reduction of Muscle Contractions during Irreversible Electroporation Therapy Using High-Frequency Bursts of Alternating Polarity Pulses: A Laboratory Investigation in an Ex Vivo Swine Model

Michael B Sano; Richard E Fan; Kai Cheng; Yamil Saenz; Geoffrey A Sonn; Gloria L Hwang; Lei Xing

doi:10.1016/j.jvir.2017.12.019

Reduction of Muscle Contractions during Irreversible Electroporation Therapy Using High-Frequency Bursts of Alternating Polarity Pulses: A Laboratory Investigation in an Ex Vivo Swine Model

J Vasc Interv Radiol. 2018 Jun;29(6):893-898.e4. doi: 10.1016/j.jvir.2017.12.019. Epub 2018 Apr 6.

Authors

Michael B Sano¹, Richard E Fan², Kai Cheng³, Yamil Saenz⁴, Geoffrey A Sonn², Gloria L Hwang⁵, Lei Xing³

Affiliations

¹ Department of Radiation Oncology and Division of Radiation Physics, Stanford University Medical Center, Stanford, California; University of North Carolina/North Carolina State University Joint Department of Biomedical Engineering, 4130 Engineering Building III, Campus Box 7115, Raleigh, NC 27695. Electronic address: mikesano@med.unc.edu.
² Department of Urology, Stanford University Medical Center, Stanford, California.
³ Department of Radiation Oncology and Division of Radiation Physics, Stanford University Medical Center, Stanford, California.
⁴ Department of Radiology, Stanford University, Stanford, California.
⁵ Department of Radiology and Division of Vascular and Interventional Radiology, Stanford University Medical Center, Stanford, California; Department of Radiology, Stanford University Medical Center, Stanford, California.

PMID: 29628296
DOI: 10.1016/j.jvir.2017.12.019

Abstract

Purpose: To compare the intensity of muscle contractions in irreversible electroporation (IRE) treatments when traditional IRE and high-frequency IRE (H-FIRE) waveforms are used in combination with a single applicator and distal grounding pad (A+GP) configuration.

Materials and methods: An ex vivo in situ porcine model was used to compare muscle contractions induced by traditional monopolar IRE waveforms vs high-frequency bipolar IRE waveforms. Pulses with voltages between 200 and 5,000 V were investigated, and muscle contractions were recorded by using accelerometers placed on or near the applicators.

Results: H-FIRE waveforms reduced the intensity of muscle contractions in comparison with traditional monopolar IRE pulses. A high-energy burst of 2-μs alternating-polarity pulses energized for 200 μs at 4,500 V produced less intense muscle contractions than traditional IRE pulses, which were 25-100 μs in duration at 3,000 V.

Conclusions: H-FIRE appears to be an effective technique to mitigate the muscle contractions associated with traditional IRE pulses. This may enable the use of voltages greater than 3,000 V necessary for the creation of large ablations in vivo.

MeSH terms

Animals
Electroporation / methods*
Female
In Vitro Techniques
Liver / pathology*
Models, Animal
Muscle Contraction / physiology*
Swine