US 12,433,668 B1
Impedance stoppage mitigation during radiofrequency tissue ablation procedures
Brian W. Donovan, San Jose, CA (US); and Alexander Pruitt, San Jose, CA (US)
Assigned to Relievant Medsystems, Inc., Edina, MN (US)
Filed by Relievant Medsystems, Inc., Edina, MN (US)
Filed on Nov. 7, 2022, as Appl. No. 18/053,284.
Claims priority of provisional application 63/277,100, filed on Nov. 8, 2021.
Int. Cl. A61B 18/14 (2006.01); A61B 18/12 (2006.01); A61B 18/00 (2006.01)
CPC A61B 18/148 (2013.01) [A61B 2018/00434 (2013.01); A61B 2018/00577 (2013.01); A61B 2018/00702 (2013.01); A61B 2018/00714 (2013.01); A61B 2018/00732 (2013.01); A61B 2018/00755 (2013.01); A61B 2018/00761 (2013.01); A61B 2018/00791 (2013.01); A61B 2018/126 (2013.01)] 20 Claims
OG exemplary drawing
 
1. A radiofrequency tissue ablation system configured to reduce occurrences of impedance-related stoppages of radiofrequency energy delivery during a radiofrequency tissue ablation procedure, the system comprising:
a radiofrequency probe comprising one or more electrodes and one or more temperature sensors;
a radiofrequency generator comprising a power source electrically coupled to the one or more electrodes and one or more processors operatively coupled to the power source and to the one or more temperature sensors,
wherein the one or more processors are configured to execute program instructions stored in memory of the radiofrequency generator that, when executed:
cause the power source to deliver radiofrequency energy to the one or more electrodes, the radiofrequency energy being sufficient to provide controlled heating of tissue surrounding the one or more electrodes; and
cause the radiofrequency generator to transition between a steady-state phase of operation and an impedance-limiting phase of operation so as to reduce temperature and tissue impedance prior to initiation of an automated impedance-related stoppage of radiofrequency energy delivery during a radiofrequency tissue ablation procedure,
when operating in the steady-state phase, the one or more processors are configured to:
receive temperature measurements from the one or more temperature sensors;
calculate a magnitude and a rate of change of tissue impedance based on signals received from the one or more electrodes; and
automatically transition to the impedance-limiting phase of operation when one or more trigger criteria are met; and
when in the impedance-limiting phase of operation, the one or more processors are configured to:
cause the power source to temporarily reduce power output to reduce temperature to a lower threshold temperature and to ramp power output back up after achieving the lower threshold temperature.