Ultrasound-Guided Percutaneous Cryoneurolysis to Treat Postoperative Pain After Mastectomy

Cryoneurolysis of the 2nd-6th thoracic intercostal nerves will be treated on the ipsilateral surgical side (bilaterally for bilateral surgical procedures): for each nerve the cryoneurolysis device will be triggered using 2 cycles of 2-minute gas activation separated by 1-minute defrost periods (Epimed) or 1 cycle of 5.5 minutes \[all but 4 participants: 064-067\] or 3 minutes \[only 4 participants 064-067; change based on new laboratory data, then changed back based on inadequate freeze\] of argon and 30 seconds of helium (Varian). For active probes, the gas will be deployed to the tip where a drop in temperature to approximately -70°C will result in cryoneurolysis.

Sham cryoneurolysis of the 2nd-6th thoracic intercostal nerves will be applied on the ipsilateral surgical side (bilaterally for bilateral surgical procedures): for each nerve the cryoneurolysis device will be triggered using 2 cycles of 2-minute gas activation separated by 1-minute defrost periods (Epimed) or 1 cycle of 5.5 minutes \[all but 4 participants: 064-067\] or 3 minutes \[only 4 participants 064-067; change based on new laboratory data, then changed back based on inadequate freeze\] of argon and 30 seconds of helium (Varian). However, for sham probes, the gas is not deployed to the tip and therefore there is no drop in temperature resulting in cryoneurolysis.