There may be new hope, however, as scientists now report that exposing damaged nerves to a cold needle can cause them to regenerate, drastically reducing pain.

The procedure, which could be performed by an interventional radiologist, is called interventional cryoneurolysis.

In a nutshell, it involves freezing a hypodermic needle, inserting it beneath the patient's skin, then using CT-scanning technology to guide it into contact with a damaged nerve. Doing so initially causes the nerve to degenerate, losing its functionality, but then regenerate as a healthy new nerve.

"There are five grades of peripheral nerve injury which were classified by a famous neurosurgeon named Sunderland. They range from partially injured (Sunderland 1) to completely transected and beyond repair (Sunderland 5)," said the lead author of a study on the technique, Assoc. Prof. J. David Prologo of Emory University in Atlanta, Georgia.

"What happens to a nerve after a Sunderland 2 injury is that it degenerates, and then regenerates. This will not happen following a Sunderland 1 or Sunderland 3 thru 5 [...] By exposing the nerve to the right amount of cold, for the right amount of time, over the right area on purpose – the very specific Sunderland 2 nerve injury can be induced. So, we are inducing the body's ability to naturally regenerate that nerve by being able to take that diseased/damaged nerve and inducing a Sunderland 2."

Prologo and colleagues tested the treatment on eight patients with chronic nerve pain. The average time that had elapsed since the occurrence of the nerve-damaging injury was 9.5 years.

No negative side effects were observed in any of the test subjects, and all of them regained full use of the affected limb over time. According to the scientists, this fact confirms that the damaged nerve successfully regenerated. Additionally – and importantly – six of the participants reported a dramatic reduction in pain.