Cold blast treatment relieves phantom limb pain, study finds

For the 85 percent of amputees who suffer from phantom limb pain, finding relief may seem hopeless. But a new study from Emory University has found a technique that significantly reduces the painful sensations amputees feel in their removed limbs.

“It was amazing, the very next day, all that aching and pain were gone,” study participant Charles “Thom” Presley, 59, told FoxNews.com. “I still had the sensation that my foot was there— I could still wiggle my toes that weren’t there— but I have had no trouble since with the pain at all. It’s just brilliant, absolutely brilliant.”

Presley is one of 20 patients who were part of the Emory University study on the use of cryoablation therapy, a minimally invasive targeted treatment that uses cold blasts to reduce phantom limb pain. The study, which was presented Wednesday at the Society of Interventional Radiology’s 2016 Annual Scientific Meeting, was led by Dr. J. David Prologo, an assistant professor in the division of interventional radiology at Emory University School of Medicine.

“Essentially what we see is for a great majority of patients, if we had 100 patients undergo therapy, we can expect 85 of them to respond,” Prologo told FoxNews.com of the three studies the team has done on phantom pain and cryoablation therapy, which uses a pen-tip sized needle to shut down the nerve responsible for the pain.

For this study, the participants rated their pain on a 10-point scale before treatment, seven days post-treatment and again at 45 days after. Prior to cryoablation, the average pain score was 6.4. By day 45, the average score was 2.4 points.

According to the Amputee Coalition, 2.1 million people live with limb loss and 185,000 people have an amputation each year.

What is phantom limb pain?
For individuals with amputations, phantom limb pain seems to arise from the part of the limb which has been removed. The sensation occurs when there is an interruption of the nerve that supplied the removed body part. Normally, it would send signals from that body part to the brain, but when there is amputation, several things may occur: A scar may form at the end of the nerve, other nerves may be confused by the missing limb and send out false signals, the brain may reorganize itself in response to missing input from the amputated limb, or other nerves may get “ramped up” and feed into the pathway.

Patients present with well-defined pain, Prologo said, specifying, for example, a stabbing pain on the bottom of the foot or the outside of the pinky toe. Since nerves are all assigned to certain parts of the body, researchers are able to trace the nerve responsible for the phantom pain.

The condition is hard to treat because each phantom limb patient is unique and input from each of the points on the neural pathway is different, making it difficult to create a treatment that works for all patients, researchers noted.

Standard treatments for phantom limb pain include psychological interventions, anti-depressants, anti-anxiety medications and opioids, as well as mirror therapy, where the patient looks in the mirror at his remaining limb and watches the reflection, so it appears that both the good limb and remaining stump are moving.

“Current treatments are from stem-to-stern— psychological to psychiatric and everywhere in-between— but none are particularly effective,” Prologo said.

With cryoablation, the probe is placed in proximity to, or next to the responsible nerve— which has been located by image guidance and CT-scan guidance— and the temperature is dropped for 25 minutes, shutting down nerve signals in the targeted area.

For the study, patients first described their symptoms in an office consultation to confirm they had phantom limb pain as opposed to residual limb pain in the remaining stump. During that visit, the team determined which nerve was responsible for the pain described. Then, the patient was administered numbing medicine and a small amount of steroid around the nerve in order to temporarily shut down the nerve to confirm it was related to the pain. The patient was then scheduled for cryoablation and, after undergoing treatment, was monitored for 24 hours for safety and 45 days proceeding.

The Emory study included 20 patients and overall the pain averages came down, but two of the patients reported their pain remained the same.

Moving forward, the team has applied for a grant to study if they can predict who will best respond to cryoablation therapy. They plan to design a multi-center trial, including the San Antonio Military Medical Center — Prologo added that it is the largest military hospital in the U.S. to treat the greatest number of amputees— to study 140 participants.

This next step will take three years, during which time researchers will evaluate whether their treatment is effective and safe on a large scale, then disseminate it for use. The team has already appealed for a American Medical Association procedure code, which is important because it ensures a medical practitioner will be reimbursed by health insurance, Prologo said.

As for any risks with cryoablation therapy, Prologo said they had a few cases of swelling, but no complications that required additional treatment. Undergoing any procedure is a risk, he added.

“When I talk to patients, I tell them from my experience, the biggest risk is undergoing a procedure that may not help, even with that it’s a 10 percent risk,” he said.

“It was such a blessing”
For study participant Presley, cryoablation therapy has been a “blessing,” he said.

The Cherry Log, Georgia, man’s left foot was amputated below the knee around Easter 2015. By July, as he was starting to prepare for physical therapy, he felt stabbing pain that kept him awake at night.

“The phantom pain was unbelievable. I had a dull ache in my absent foot behind the toes. Once I got a prosthetic and was learning in PT how to use it, it became extremely painful,” Presley said. “It really interfered with my learning to walk again.”

Presley’s primary care physician had recommended Lyrica, but Presley was only able to afford the generic form under Medicaid and the medication didn’t help his pain and made him “feel very goofy all day,” he said. Plus, taking four daily doses was a hassle and he was getting up in the middle of the night and walking— without his prosthetic— and therefore falling on the floor.

“Really there was nothing anybody could offer other than to say, ‘Live with it or don’t take the [medication] and the pain will be worse,’” he said. “When I discovered Dr. Prologo, it was such a blessing, I swear.”

Presley underwent cryoablation therapy on October 31. The worst part was the freezing blasts that made his muscles contract like a painful cramp, but since he was under anesthesia, it wasn’t that bad, he said.

Since undergoing the therapy, he hasn’t experienced any side effects from the cryoablation therapy. While he remains in a wheelchair due to diabetes-related issues in his right foot, his goal is to walk again and ride an electric bicycle again.

“Don’t let anybody tell you it doesn’t exist, because it does,” Presley said. “It’s hard to think something not here hurts so bad, but it does; your brain remembers.”