Northwestern researchers develop dissolving, nerve-cooling device for drug-free pain relief

As the opioid epidemic rages on, healthcare providers and scientists are still searching for a less addictive alternative to the drugs for pain relief.

A group of researchers from Northwestern University may be close to cracking the code. A study published Friday in the journal Science describes a new device they’ve developed that is implanted near the nerves to cool them down, blocking pain signals from reaching the brain.

The implant is designed to be completely absorbed into the body once it’s no longer needed, and its makers have suggested that it could be put in place during a surgical procedure that would typically require a post-op pain relief regimen—together, eliminating the need for additional procedures to implant and remove the device.

The researchers said the new device also represents a more targeted treatment than existing methods built on electrical stimulation or cryotherapy, which may cause additional pain or muscle contractions before easing them.

The implant—approximately the thickness of a sheet of paper—is soft and flexible, allowing a cuff on one end to wrap around a single nerve at a time. Once in place, separate channels of liquid coolant and dry nitrogen flow into a shared chamber, immediately causing the coolant to begin evaporating. The cooling process of evaporation lowers the temperature of the nerve, numbing it enough to stop the transmission of pain signals to the brain.

“The technology reported here exploits mechanisms that have some similarities to those that cause your fingers to feel numb when cold. Our implant allows that effect to be produced in a programmable way, directly and locally to targeted nerves, even those deep within surrounding soft tissues,” said John Rogers, Ph.D., an engineering professor at Northwestern who led development of the device and is an author of the study.

The temperature drop is monitored by a tiny sensor embedded in the device, which transmits information to an external receiver. Patients and their healthcare providers can control the therapy using that pump, ensuring that the temperature doesn’t drop too far, to levels that could potentially cause tissue damage.

“By monitoring the temperature at the nerve, the flow rates can be adjusted automatically to set a point that blocks pain in a reversible, safe manner,” Rogers said. “Ongoing work seeks to define the full set of time and temperature thresholds below which the process remains fully reversible.”

When the treatment period is complete, the implant’s completely water-soluble components are fully and safely absorbed by the body’s biofluids over the span of days and weeks.

Aside from the many neurostimulation devices already on the market, a handful of other technologies under development are taking similarly creative approaches to opioid-free pain relief. At the end of last year, for example, the FDA approved a system from AppliedVR that treats chronic lower back pain via virtual reality headsets, providing cognitive behavioral therapy in games, lessons and exercises for pain reduction.