Cryoanalgesia or cryoneurolysis is a technique that produces prolonged analgesia by applying cold to peripheral nerves. The analgesic effects of cold or freezing have been historically documented as far back as Hippocrates (460-377 BCE). The earliest written records reveal the use of ice as cold packs applied to tissue prior to surgery. Medieval physicians such as Avicenna of Persia (982-1070 AD) and Severino of Naples (1580-1656) also used cold as a means of freezing tissue prior to surgery. Even during wartime in 1812, Napoleon's surgeon general (Baron Dominique Jean Larre) recognized that limbs of soldiers frozen in ice and snow could be amputated without significant pain. In 1851, Dr. James Arnett noted that a mixture of ice and salt at -20°C could produce hemostatic and anesthetic effects on tumors.1 The modern era of cryoneurolysis began with the development of effective and controllable cold delivery systems. In 1962, Dr. Irvine Cooper developed a cryotherapy unit in which liquid nitrogen was circulated through hollow cryoprobes that were thermally insulated except at the tip. Cryoprobe tip temperature could achieve a nadir of -190°C. At about the same time, Dr. S. Amoils developed a simple hand-held instrument in which highly pressurized gas (carbon dioxide or nitrous oxide) could be used to achieve tip temperatures of -70°C. These devices were the prototypes for the current generation of cryo probes.