Over 50 million American adults suffer from chronic pain, and many use opioids to help manage their symptoms.
A research team at Northwestern University has developed an implantable device that wraps around peripheral nerves and cools them to prevent signaling.
The implant delivers treatment in a more targeted manner and absorbs into the body after a period of weeks.
Americans struggle with pain. According to data gathered in the CDC’s 2019 National Health Interview Survey, 50.2 million adults in the US have chronic pain.
But hope may be in sight for those suffering with such pain. A 2022 study published by researchers at Northwestern University describes the development of a new implantable device designed to alleviate pain without the use of any prescription medications.
This soft, flexible device is the first of its kind. While it is not yet approved for use in humans, it may ultimately provide an effective alternative to opioids and other potentially addictive drugs.
Sources of chronic pain
According to the CDC data, over a 3-month time period, 4.4% of adults with chronic pain used only opioids for symptom relief. A full 10.7% used a combination of opioids and other nonopioid therapies, such as complementary therapies.
In many cases, chronic pain results from acute injury, accidents, or planned surgical procedures.
While analgesics like opioids provide pain relief, their regular use may lead to dependency, addiction, accidental overdose, and death.
Alternative pain therapies, such as cryotherapy and nerve blockers, have been investigated and included in various treatment plans. However, these alternative pain management methods often have limitations, and they may not be as effective as opioids for chronic pain management.
For these reasons, researchers have investigated alternative pain-relief methods such as the recently developed implant.
Device wraps around nerves to cool them
The new implant uses evaporation to directly cool down peripheral nerve fibers, eventually stopping pain signals traveling to the brain.
The device contains two microfluidic channels. One contains the liquid coolant perfluoropentane, which is already clinically approved for use in pressurized inhalers and as an ultrasound contrast agent. The other channel contains dry nitrogen, a chemically inactive gas.
An external pump enables the patient to activate the implant. When activated, the contents of both channels combine, causing a chemical reaction in which the liquid coolant quickly evaporates.
While this occurs, a small sensor integrated into the implant monitors the temperature of the target nerve, preventing it from becoming damaged by the cold. The device’s intensity can be increased or decreased by the patient, depending on preference and medical need.
The device has one end that curls into a soft cuff and gently wraps around a single peripheral nerve. At its widest point, the implant is 5 millimeters (mm) wide. Since it physically wraps itself around a nerve, sutures are unnecessary.
The implant biodegrades over a period of weeks. Researchers believe it can be placed during planned surgical procedures to help manage postoperative pain without the need for surgical extraction.
Benefits include more localized response
Other pain management treatments, such as cryotherapy, can mitigate symptoms, but often not without risk.
Cryotherapy, for example, is delivered via injection and does not target specific tissues. Instead, large areas of tissue are cooled at once, potentially leading to inflammation or tissue damage.
Other therapies, such as electrical nerve stimulation, can also provide pain relief, but they may also result in unwanted side effects. Electrical nerve stimulation works by preventing a nerve from sending impulses to the brain. However, this technology often first activates the nerve, causing additional pain or muscle contractions at the target area.
Since the implantable device physically wraps around target nerves, treatment is delivered in a much more precise manner. The external pump, which is controllable by the user, can dial the device’s effects up or down, making treatment much more personalized to each individual’s unique needs.
And because the device is water-soluble and biocompatible, it naturally absorbs into the body after a specified period of time, much in the same manner as absorbable sutures.
To date, the device’s efficacy has only been tested in animal models.
Further research, including testing in human subjects, will be necessary to determine its true effectiveness and safety profile.
What this means for you
Researchers at Northwestern University have developed a first-of-its-kind implantable device which provides targeted, cooling pain relief directly to peripheral nerves. The device is not yet approved for use in humans, but it may eventually provide an alternative to opioids and other highly addictive drugs.