The Cold Hard Facts on Cryo

Pain Management

By: Jared Bilski

Published: 3/9/2021

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With a variety of applications, the demand for cryoanalgesia is increasing at outpatient facilities.


COOL COMFORT Jon Wilton, DNAP, CRNA, performs cryoanalgelsia to manage pain associated with total shoulders and knees, rib fractures and sensory nerve neuropathy.   |  Benjamin S. Nuti

Numbing nerves with local anesthetics relieves post-op pain for days at a time. Freezing them with a blast of targeted cold therapy can provide the same soothing effect for weeks or even months. "Cryoanalgesia has the potential to reduce the reliance on traditional opioid-based pain management strategies," says Jon Wilton, DNAP, CRNA, chief nurse anesthetist at Mercy Medical Center Mt. Shasta (Calif.). "Limiting opioid use reduces associated side effects, including addiction, and facilitates early post-op mobility."

Cryo is performed percutaneously by guiding a closed probe next to a nerve. Carbon dioxide or nitrous oxide is passed through the probe until the gas reaches the probe's tip and the pressure drops, which results in a drastic cooling. The end result is the creation of an ice ball that encompasses the targeted nerve, freezes and disables it, and keeps patients pain-free for extended periods.

The potency of this pain-relieving treatment is one of the major reasons facilities are increasingly looking at cryo in their quest to improve patient comfort with fewer opioids. It's also why the treatment is beginning to pique the interest of surgical professionals who want to advance the management of post-op pain with longer-lasting analgesia.

Straightforward and effective

NEW CLASS Almost all anesthesiologists coming out of residency are now trained in how to place ultrasound-guided peripheral nerve blocks.

If the process of cryo — targeting specific nerves and blocking the pain sensation in that area — sounds familiar, it's because, for all practical purposes, it's similar to placing a standard regional block. "When we say peripheral nerve block, everybody thinks local anesthesia, but cryoanalgesia is a peripheral nerve block," says Brian M. Ilfeld, MD, MS, a professor of anesthesiology in residence in the department of anesthesiology at the University of California San Diego and a leading voice in applying cryo to treat surgical pain.

That's important because there's a lot of misconceptions about what it takes to perform cryo, primarily that the procedure is overly complicated. "This is patently false," says Dr. Wilton. "The landmark-based knee application of cryo is simple to implement and is relatively easy to master if you are already ultrasound-proficient."

The latter point should apply to virtually all new anesthesia providers. "Almost all anesthesiologists coming out of residency are trained in how to place ultrasound-guided peripheral nerve blocks," says Dr. Ilfeld, "and almost all local surgery centers and hospitals have ultrasound equipment, so we don't have to fight to get the equipment like we did 10 years ago."

Even so, comprehensive training is an absolute must for any of your anesthesia providers who perform cryo. "Providers must be skilled in ultrasound-based needle placement using a targeted in-plane approach — the needle enters the skin at the side of the probe — to confirm the location of the probe's tip," says Scott Rigdon, MPH, DNAP, CRNA, NSPM-C, a anesthesia professional based in Southwest Montana. "It's also essential to undergo some formal coursework and perform several cryo procedures with a mentor or in the presence of a device rep."

Multiple applications

Cryo is FDA approved for use on any sensory nerve and has a number of practical applications that can be put to good use by innovative, forward-thinking facilities. For instance, surgeons often encourage patients to lose weight before joint replacement surgery. But if patients are suffering from severe joint pain, it's difficult for them to exercise. In these instances, anesthesia providers can use cryo about a month before procedures to reduce their pain and help them better prepare for their surgeries.

I believe all facilities have a responsibility to explore interventions based on nonopioid-based pain management.
— Jon Wilton, DNAP, CRNA

At Mercy Mt. Shasta, Dr. Wilton uses cryo multiple times per week to help patients prepare for surgery, treat chronic pain and reduce the opioid prescriptions needed following notoriously painful procedures such as total shoulders and total knees. He also regularly uses the treatment for rib fractures and occasionally for other sensory nerve neuropathies where rapid onset is desired or potential dysesthesia could be an issue. In terms of technique, Dr. Wilton prefers to use a 90mm stim needle under ultrasound guidance whenever possible. He identifies the target nerve via ultrasound and preps and numbs the skin around the planned insertion site. "A pilot hole is created with an 18-gauge needle before the stim needle is inserted and advanced to the target nerve, almost always under ultrasound guidance," explains Dr. Wilton. He then uses the stim needle to guide the cryo probe to the nerve.

Dr. Rigdon estimates he performs approximately 10 cryo procedures per month. "We use it for diagnostic and therapeutic inventions, before total knee replacements and to help increase patients' participation in physical and occupational therapies."

Like Dr. Wilton, the most common cryo procedures Dr. Rigdon performs are done via in-plane ultrasound guidance to confirm the terminal needle placement. The procedure produces a lesion in the peripheral nerve tissue by applying cold therapy to the selected site, and blocks the pain signal that the site would send to the brain. Patients are contacted soon after the procedure to ensure there are no unexpected issues. "We always follow up with patients by phone within 72 hours of their treatments," says Dr. Rigdon.

A promising future

Dr. Ilfeld is quick to point out that cryo has a highly variable duration. "Pain relief sometimes lasts multiple weeks, and sometimes is lasts multiple months," he says. "There have been cases that have lasted nine months." That variability in the consistency of duration is a limitation, notes Dr. Ilfeld.

Still, he sees a lot of potential in cryo and expects use of the treatment to increase significantly in outpatient surgical facilities moving forward, especially with the advent of minimally invasive delivery methods. Before that can happen, however, he says more data is needed to prove the effectiveness of this form of analgesia in the surgical setting. "Historically, cryo has been mainly used to treat chronic pain, so now we're looking to see how this technique can be applied to acute pain," says Dr. Ilfeld. "We currently don't have the randomized trials to provide us the information needed to optimize postoperative cryoanalgesia for our patients."

That data might not yet be available, but diligent investigators like Dr. Ilfeld are doing their part to ensure reliable and valid research is published in the near future. In fact, Dr. Ilfeld is leading a number of randomized trials to examine the potential benefits of cryo in treating acute pain. (You can download one of his papers at outpatientsurgery.net/forms.) What he's discovered thus far has been quite promising. For instance, in a recent editorial published in the British Journal of Anaesthesia, Dr. Ilfeld says current evidence suggests that ultrasound-guided percutaneous cryo holds enormous potential for making a dramatic leap forward in providing long-term analgesia far surpassing typical continuous peripheral nerve blocks, with minimal risk and a lower patient burden.

Providers who already use cryo regularly, such as Dr. Wilton, expect its usage to ramp up in the future. "There is an increase in interest for alternative targets, including the hip, shoulder, intercostal space, greater occipital nerve and many other sensory nerve neuropathies," he says.

Like all emerging interventions, the most compelling reason for adoption is improved patient care. "I believe all facilities have a responsibility to explore interventions based on nonopioid-based pain management," says Dr. Wilton. Based on the already available evidence, cryo is certainly worth exploring. OSM

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