Abstract No. 269 Cryoablation Probe with Thermoelectric Cooling for Cryoneurolysis

Cryoneurolysis is a percutaneous technique that offers long-term pain relief in interventional pain therapy. The procedure aims to achieve second degree nerve injury by exposing the nerves to temperatures between -20°C and -100°C. This injury disrupts the axon but maintains the integrity of other nerve structures, allowing for potential nerve regeneration over 3 to 24 months. Modern cryoablation devices rely on the Joule-Thomson effect that involves handling of volatile, pressurized gasses. These gases require specialized handling and storage conditions, which pose safety and cost challenges. The study explores an alternative method using thermoelectric cooling, mitigating the limitation of existing devices. We leveraged the Peltier effect, the temperature difference created by an electric current flowing through two distinct semiconductors to achieve thermoelectric cooling. Our cryoprobe design incorporated these semiconductors between ceramic plates, facilitating efficient heat transfer. Importantly, we integrated a heat pipe into the probe as the needle, which transported the cryogenic temperatures from the thermoelectric module to the needle tip. This design allowed rapid and effective transfer of cold temperatures to the target site. The methodological advantage of thermoelectric cryoneurolysis lies in its reversibility. By simply altering the direction of the current flow, the hot and cold surfaces of the probe can be switched, thus enabling rapid tissue freezing and thawing during the procedure. This flexibility may enhance the clinical applicability of cryoneurolysis, providing more control over the procedure. Initial experimental evaluations demonstrated its ability to regulate and fluctuate the temperature of the cryoprobe tip in the therapeutic ranges. The cooling phase reached suitable freezing temperatures, adequate to induce axonotmesis. Subsequently, the probe tip was able to thaw the affected area and further facilitate effective treatment. The repeatable cycles of freezing and warming showed the system's capability in managing precise temperature control, proving the potential for a consistent, targeted approach in pain management therapy. The proposed cryoablation device utilizing the thermoelectric effect shows promise for providing enhanced, efficient, and controlled pain relief in interventional pain therapy.