A better definition of obesity
January 14, 2025
A reliable method to treat post-amputation pain remains elusive, but a new Northwestern Medicine study conducted in collaboration with Ukrainian physicians suggests that hydrodissection — a simple procedure that injects fluid around nerves — may reduce residual limb pain and opioid dependence.
The study, published in Regional Anesthesia & Pain Medicine, is the first to evaluate hydrodissection for post-amputation pain, a condition affecting millions worldwide that is notoriously difficult to treat.
“Adding hydrodissection to opioid treatment for post-amputation pain not only appears to improve pain outcomes, but also shows mental-health benefits,” said senior study author Dr. Steven P. Cohen, a professor of anesthesiology and the vice chair of research and pain medicine at Northwestern University Feinberg School of Medicine.
For young veterans, finding safer alternatives to opioids is especially crucial, because many face a high risk of opioid dependence due to severe psychological trauma, he said.
Cohen, who traveled to Ukraine to set up the study, is a retired U.S. Army colonel who served four overseas tours in support of military operations and father to a son currently in the infantry.
A remarkably simple procedure
Hydrodissection is an ultrasound-guided procedure where fluid is injected into scar tissues around nerves to relieve pressure, reduce inflammation and promote healing. While the technique has shown promise for acute and neuropathic pain, its effectiveness for post-amputation pain, specifically, had not been previously studied.
“It’s remarkable how simple and accessible this technique is — requiring just an ultrasound and a needle,” Cohen said.
How the study was conducted
Scientists followed 74 Ukrainian soldiers and civilians who had undergone traumatic limb amputations due to war injuries. Thirty-eight patients received hydrodissection alongside opioid therapy within six months of amputation, while 36 received opioids alone.
The study showed that hydrodissection combined with opioids provided better pain relief and reduced opioid use. On a 0–10 pain scale, the hydrodissection group reported an average pain reduction of 4 points, compared to 3 points for those on opioids alone — a significant difference considered clinically meaningful in most studies.
Additionally, nearly two-thirds of patients in the hydrodissection group reduced their opioid use, while only about one-third of the opioid-only group did. Patients receiving hydrodissection also reported lower anxiety levels. However, its effects on phantom limb pain and chronic pain were more limited.
Findings are ‘highly relevant to Americans’
Post-amputation pain is a major challenge for both veterans and civilians worldwide, often preventing amputees from using prosthetics and reducing their quality of life.
An estimated 100,000 Ukrainians have suffered war-related amputations since Russia’s full-scale invasion of Ukraine. In the U.S., more than 2 million people live with limb loss, a number that is expected to rise sharply due to aging populations and increasing rates of diabetes and vascular disease.
“This research is highly relevant to Americans,” Cohen said. “Trauma is the leading cause of upper-extremity amputations worldwide, and post-amputation pain affects most amputees, limiting their reintegration into society.”
Additionally, the simplicity of hydrodissection means the procedure could be easily adopted by most community hospitals in the U.S., Cohen said.
Returning to Ukraine
Given the challenges of conducting research during wartime, the study was exploratory, not controlled. Still, Cohen intends to return to Ukraine this spring to launch new randomized trials focused on novel treatments for post-amputation pain, traumatic brain injury, and PTSD — undeterred by the dangers of working in a conflict zone.
Cohen is also analyzing data on botulinum toxin injections for amputees and examining how mental health factors, such as depression and anxiety, impact phantom limb pain and recovery outcomes.