Anesthesiology. 2026 Mar 23. doi: 10.1097/ALN.0000000000006059. Online ahead of print.
ABSTRACT
BACKGROUND: Cryoneurolysis provides analgesia by reversibly ablating peripheral nerves using gas-induced exceptionally low temperature. The desired therapeutic temperature is between approximately -20°C and -100°C. Warmer temperatures can induce a neuropraxia that may itself induce pain; and colder temperatures can result in permanent nerve injury. Therefore, it is imperative that the target nerve reach but not exceed the therapeutic window.
METHODS: A convenience sample of participants undergoing mastectomy (n=3) received a high-thoracic paravertebral nerve block, while subjects being treated for traumatic rib fractures (n=3) did not. All participants had ultrasound-guided cryoneurolysis of multiple intercostal nerves with a percutaneous thermocouple inserted approximately 3 mm adjacent to the cryoprobe shaft. The returning argon gas and tissue temperatures were correlated. Due to the limited sample size, the data are presented and not statistically analyzed.
RESULTS: Although in all cases (31 nerves) the returning gas was ultimately colder than -80°C, the tissue adjacent to the probe did not reach -20°C after 3 and 5 min in 71% (n=5) and 42% (n=10) of treatments, respectively. The coldest mean temperature in adjacent tissue was 60 degrees warmer than the returning gas without a nerve block, and 95 degrees warmer with a concurrent nerve block. When treating adjacent intercostal nerves, the gas temperature remained unchanged while the tissue became colder with each consecutive treatment.
CONCLUSIONS: During percutaneous cryoneurolysis, the temperature of tissue is frequently deceptively warm relative to the returning gas and tissue frequently does not reach an adequately cold temperature; prolonging gas treatment from 3 to 5 min improves the success of reaching therapeutic temperatures; the presence of a peripheral nerve block appears to lessen the chance of reaching therapeutic temperatures; and caution is warranted when treating consecutive intercostal nerves as tissue temperature may decrease with each level.
PMID:41870345 | DOI:10.1097/ALN.0000000000006059
