Dr. Vinod Dasa, assistant professor of clinical orthopaedics at Louisiana State University Health Sciences Center in New Orleans, has scheduled a revision knee replacement for a 62-year-old female patient. But in the meantime, he’s relieved her chronic knee pain by freezing a peripheral sensory nerve with three needles through which very cold and highly pressurized liquid nitrous oxide is delivered. At the site of the target nerve, the N2O changes phase from liquid to gas, which is expelled out from the hand-held delivery device, leaving nothing behind but a frozen nerve. The degeneration of the nerve is temporary, and it eventually regenerates. The resulting pain relief can last up to three months, at which time pain signals flow once again.
This technique, trademarked as Focused Cold Therapy™, received FDA approval in 2013 for use as a reversible peripheral nerve block. According to Dr. Dasa, “Focused cold therapy offers reliable pain relief in areas such as the knee, which may allow for physical therapy to proceed and even reduce the need for systemic pain relievers.”