Injectable Ice Slurry Cooling Technology for Treatment of Postoperative Pain

Project SummaryTotal knee arthroplasty (TKA) is one of the most commonly performed orthopedic surgeries to relieve
joint pain in patients with end-stage osteoarthritis or rheumatic arthritis. In the United States, over 700,000 TKA
procedures are performed each year. Most patients experience significant pain after TKA. To manage this
pain, patients are commonly prescribed opioids, contributing to a spiraling opioid epidemic. The misuse and
addiction to opioids is a national public health crisis with an estimated economic burden of $78.5 billion per
year. As opioid addiction has become a national emergency, novel non-opioid and non-pharmacological
treatments for postoperative pain have become a top scientific priority. There is an urgent need for a long-
lasting, drug-free means of relieving post-TKA pain–which is the overall goal of this project. Cryoneurolysis is
an opioid-sparing, perioperative intervention used to reduce postoperative pain. Current cryoneurolysis
methods apply very low-temperature cryoprobes to freeze peripheral nerves, resulting in reversible and long-
lasting pain relief. However, due to the use of extremely cold temperatures (–60oC and below) in direct contact
with a nerve and surrounding tissues, these methods are not nerve-selective nor easy to administer. They also
are not injectable, making the treatments time-consuming and challenging to adopt in clinic. We aim to develop
a novel, injectable method of cryoneurolysis to reduce postoperative pain from TKA, significantly reducing or
eliminating the use of opioids.We invented and developed a novel injectable and nerve-selective method of cryoneurolysis that
overcomes the limitations of currently available treatments. Our proprietary technology employs a formulated,
biocompatible ice-slurry consisting of small ice particles suspended in solution that can be injected around
sensory peripheral nerves that transmit pain. We have shown in a rat model that injection of our formulated ice-
slurry extracts enough heat to reversibly disrupt nerve structure and reduce pain sensation for up to 8 weeks
without damage to surrounding tissue. The advantages of this innovative technology stem from the use of an
ice-slurry mixture containing injectable ice particles, which upon melting extracts large amounts of tissue heat.
The temperature attained with the formulated ice-slurry is cold enough to cause cryoneurolysis but is not
damaging to surrounding tissues.We propose to develop a commercial prototype device that can produce proprietary on-demand,
injectable, biocompatible, and sterile ice-slurry “coolant” at the point-of-care. Proposed Phase I will establish
the technical merit, feasibility and performance of this device. We will establish that the design for custom-
made syringes can generate injectable ice-slurry and will test performance in reproducibly extracting heat.
Next, we will test both the feasibility of consistent injection through a standard clinical needle and in-vivo tissue
cooling using the rat sciatic nerve model. The results of these studies will lay groundwork for the development
of a novel, long-lasting and non-opioid treatment for patients with post-TKA pain. If successful, this new pain
management therapy will deliver on the important and urgent goal of reducing opioid use.Project Narrative
The use of opioids after knee replacement surgery to control pain is a major contributor to the opioid epidemic.
We developed a cooling solution technology that, with one injection, reduces pain for up to 8 weeks. Our goal is
to develop a device that makes the injectable solution at point-of-care to allow clinicians to treat postoperative
knee pain. A non-opioid, long-lasting therapy that reduces post-surgery pain will significantly stem opioid use.