The first-of-its-kind small flexible implant wraps around nerves to provide targeted cooling that blocks pain signals to the brain. A new device that could be an effective alternative for pain relief has been developed by researchers. The small stretchable device can be implanted under the skin to provide targeted pain relief without the need for addictive pain medication. “Although opioids are extremely effective, they also are extremely addictive,” Says Professor John Rogers, who led the device’s development in a statement. “As engineers, we are motivated by the idea of treating pain without drugs — in ways that can be turned on and off instantly, with user control over the intensity of relief. 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.” Rogers and team report their design and demonstrate its effectiveness in an animal model in the journal Science. So how does it work? It's actually a very common principle: evaporation. Similar to how sweat cools our body, the device contains a cooling liquid that can be induced to evaporate on demand at a specific target area to cool down a sensory nerve. This action can be controlled externally by a pump that allows the user to remotely increase or decrease the intensity. “As you cool down a nerve, the signals that travel through the nerve become slower and slower — eventually stopping completely,” says study co-author Dr Matthew MacEwan “We are specifically targeting peripheral nerves, which connect your brain and your spinal cord to the rest of your body. These are the nerves that communicate sensory stimuli, including pain. By delivering a cooling effect to just one or two targeted nerves, we can effectively modulate pain signals in one specific region of the body.” The illustration shows how the implant could be injected under the skin to wrap around pain conducting nerves and block their signal to the brain. Image Credit: Northwestern University The pain-treating device has the thickness of a sheet of paper and is very elastic, making it ideal for treating highly sensitive nerves. It can be inserted under the skin of an affected area, gently wrapping around the nerves responsible for the pain signals, blocking their pathway. Moreover, the device contains an integrated sensor that monitors the temperature of the nerve while in action to make sure it does not get too cold. “Excessive cooling can damage the nerve and the fragile tissues around it,” Rogers says. “The duration and temperature of the cooling must therefore be controlled precisely. 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. On-going work seeks to define the full set of time and temperature thresholds below which the process remains fully reversible.” What makes it even more useful is after the device completes the pain relief at the target area, it just dissolves into the body without the need for surgical removal, making it very patient-friendly. Although the new device could provide a much-needed approach to treating pain in the future compared to addictive pain medications such as opioids, it's worth mentioning that the current study only demonstrated effectiveness in an animal model. Future studies would need to investigate whether the device and its workings remain effective and safe in humans. Source
