Doctors freeze nerves to knock chronic pain out cold

Dr. Moore presented the results of a study, titled "Prospective Evaluation of Cryoneurolysis for Refractory Neuralgia," a Stony Brook clinical trial involving 20 patients who received cryoneurolysis for a variety of neuralgia syndromes, at the Society of Interventional Radiology's 38th Annual Scientific Meeting in New Orleans on April 14. Dr. Moore completed more than 200 cryoneurolysis procedures for neuralgia to halt nerve pain in many areas of the body, from head to toe.

In the study, 20 patients received cryoneurolysis and were evaluated using a pain scale questionnaire immediately after treatment during one-week, one-month and three-month follow-ups after the initial procedure. Prior to treatment, patients' pain plummeted from an average of 8 out of 10 on the pain scale to 2.4 one week after treatment. Pain relief was sustained for about two months after the procedure. Pain increased to an average of 4 out of 10 on the scale after six months due to nerve regeneration, Dr. Moore said.

"Neuralgia can be difficult to treat, medicines alone often do not help relieve the intense pain patients' experience, and side effects from these medicines are common," said Dr. Moore, Associate Professor of Clinical Radiology, and Chief of Thoracic Imaging. "Cryoneurolysis is an innovative treatment option with an effect that is equivalent to removing the insulation from a wire, decreasing the rate of conductivity of the nerve. Fewer pain signals means less pain, and the nerve remains intact," explained Dr. Moore, who recommends repeat cryoneurolysis treatments as needed.

Cryoneurolysis uses a small probe that is cooled to minus 50 to minus 70 degrees Celsius, creating a freezer burn along the outer layer of the nerve. This interrupts the pain signal to the brain and blunts or eliminates the pain while allowing the damaged nerves to grow back healthy, he said.

During the procedure, an interventional radiologist makes a nick in the skin near the source of pain and inserts a tiny probe. Under CT imaging guidance, the probe is advanced through the skin to the affected nerves. Cooled with pressurized gas, the probe creates ice crystals along the edge of the nerves.

Cryoneurolysis, said Dr. Moore, generally provides an analgesic effect that lasts for weeks to months without damaging the frozen structures. The effectiveness of the treatment varies with patients, depending on the location of nerve damage. Nerves that respond well to freezing include the ilioinguinal nerves, intercostal nerves and superficial femoral nerves.

"We have been able to manage some patients' chronic neuralgia by treating them as many as six or seven times over the course of several years," said Dr. Moore. "For some patients this is a long-term, safe, and effective solution and helps minimize other methods to keeping their pain under control."