Welcome to a very exciting POTD inspired by our research extraordinaire and pain management expert Dr. Sergey Motov!
He recently enlightened me on the topic of cryoneurolysis as a pain management modality, and my first response was: what is that? So let's learn together!
What is it?
The use of cold temperature to treat pain using nitrous oxide contained within the cryoneurolysis probe/cannula. Nitrous oxide enters a low-pressure chamber at the end of the cryoneurolysis probe, which causes a precipitous decline in temperature. This decline in temperature leads to axonal injury and analgesia at the intended site. Because cryoneurolysis relies on axonal injury for analgesia, pain control can be achieved for weeks to months.
For our surgical colleagues, this may be done with direct visualization of the nerve in the OR. For the EM folks, this can be done using an ultrasound-guided approach with a percutaneous cryoneurolysis probe.
What's the evidence?
A systematic review by Cha et al. (2021) noted that cryoneurolysis may be useful for chest wall pain after surgery or trauma, however many studies are of low quality, and more research is needed. Similarly, a case series published by Wang et al. (2024) showed promising results for cryoneurolysis as pain management after rib fractures.
Other preliminary data suggest efficacy in pain control following total knee arthroplasty, rotator cuff injuries, limb amputations, and lower limb burn injuries.
However, as previously mentioned, many studies are not the highest quality (lots of case reports and case series) and more research is needed. But, so far the results are promising!
What's the downside?
Because analgesia can be achieved for weeks-months, this modality is less useful for nerves that have both motor and sensory function, as it can impair someone's motor function for a long time.
Other potential side effects are similar to those of nerve blocks, including bleeding, infection, and (longer than intended) nerve damage.
Also - this requires a specialized cryoneurolysis probe to do, so you'd potentially be limited by the resources of your practice setting.
Is this helpful for us in the ED?
Much of the literature that has come out about cryoneurolysis has been from our surgery and anesthesia colleagues. However, given that nerve blocks are becoming more and more common in EM (and certainly in the Maimo ED), doing ultrasound-guided cryoneurolysis can certainly be a pain control modality that EM providers can do.
Given that a lot of what we see in the ED relates to pain, cryoneurolysis can be an additional pain control option for patients that require long-term pain control. Many of the studies are reporting multiple weeks of pain control after cryoneurolysis. If you're giving pain control after surgery or trauma, the hope is that maybe after the weeks of cryoneurolysis wear off, the patient's injury/surgery will have healed enough that their pain will be tolerable.
Also, given the public health push to reduce routine opioid use, cryoneurolysis can aid us in providing another option to patients who are in pain.
In conclusion...
Cryoneurolysis is an old technique that has newly become a feasible pain management option in the era of modern cryoneurolysis probes and ultrasound-guided nerve blocks. While more research is needed and more training is needed for EM providers, this may be an up and coming option for longer term pain management.
References:
John J. Finneran IV & Brian M. Ilfeld (2021) Percutaneous cryoneurolysis for acute pain management: current status and future prospects, Expert Review of Medical Devices, 18:6, 533-543, DOI: 10.1080/17434440.2021.1927705
Cha PI, Min JG, Patil A, et al. Trauma Surg Acute Care Open 2021;6:e000690.
Finneran Iv JJ, Gabriel RA, Swisher MW, et al. Ultrasound-guided percutaneous intercostal nerve cryoneurolysis for analgesia following traumatic rib fracture -a case series. Korean J Anesthesiol. 2020;73(5):455-459. doi:10.4097/kja.19395
Gabriel RA, Seng EC, Curran BP, Winston P, Trescot AM, Filipovski I. A Narrative Review of Ultrasound-Guided and Landmark-based Percutaneous Cryoneurolysis for the Management of Acute and Chronic Pain. Curr Pain Headache Rep. Published online July 4, 2024. doi:10.1007/s11916-024-01281-z
Wang S, Earley M, Kesselman A, et al. Percutaneous Cryoneurolysis for Pain Control After Rib Fractures in Older Adults. JAMA Surg. Published online August 7, 2024. doi:10.1001/jamasurg.2024.2063
Ilfeld BM, Gabriel RA, Trescot AM. Ultrasound-guided percutaneous cryoneurolysis for treatment of acute pain: could cryoanalgesia replace continuous peripheral nerve blocks?. Br J Anaesth. 2017;119(4):703-706. doi:10.1093/bja/aex142