Cryoanalgesia in interventional pain management.

Cryoneuroablation, also known as cryoanalgesia or cryoneurolysis, is a specialized technique for providing long-term pain relief in interventional pain management settings. Modern cryoanalgesia traces its roots to Cooper et al who developed in 1961, a device that used liquid nitrogen in a hollow tube that was insulated at the tip and achieved a temperature of - 190 degrees C. Lloyd et al proposed that cryoanalgesia was superior to other methods of peripheral nerve destruction, including alcohol neurolysis, phenol neurolysis, or surgical lesions. The application of cold to tissues creates a conduction block, similar to the effect of local anesthetics. Long-term pain relief from nerve freezing occurs because ice crystals create vascular damage to the vasonervorum, which produces severe endoneural edema. Cryoanalgesia disrupts the nerve structure and creates wallerian degeneration, but leaves the myelin sheath and endoneurium intact. Clinical applications of cryoanalgesia extend from its use in craniofacial pain secondary to trigeminal neuralgia, posterior auricular neuralgia, and glossopharyngeal neuralgia; chest wall pain with multiple conditions including post-thoracotomy neuromas, persistent pain after rib fractures, and post herpetic neuralgia in thoracic distribution; abdominal and pelvic pain secondary to ilioinguinal, iliohypogastric, genitofemoral, subgastric neuralgia; pudendal neuralgia; low back pain and lower extremity pain secondary to lumbar facet joint pathology, pseudosciatica, pain involving intraspinous ligament or supragluteal nerve, sacroiliac joint pain, cluneal neuralgia, obturator neuritis, and various types of peripheral neuropathy; and upper extremity pain secondary to suprascapular neuritis and other conditions of peripheral neuritis. This review describes historical concepts, physics and equipment, various clinical aspects, along with technical features, indications and contraindications, with clinical description of multiple conditions amenable to cryoanalgesia in interventional pain management settings.