Minimally Invasive Procedure May Ease Carpal Tunnel Pain for Months

The findings make sense to Matthew Bollier, MD, a professor of orthopedic surgery at the University of Iowa in Iowa City, who was not involved in the research. “We know that the benefit from a steroid injection often wears off in the first few months,” Dr. Bollier says.

How Hydrodissection Works for Carpal Tunnel Syndrome

“The aim is not only to reduce symptoms temporarily, but to improve the mechanical environment of the nerve and restore its mobility,” says Dr. Mathieu, who was not involved in the new study. “Our goal is not simply to make patients feel better for a few weeks, but to achieve a meaningful and lasting improvement.”

Hydrodissection Provided Relief for at Least 6 Months

For the study, researchers enrolled 39 adults with carpal tunnel syndrome, all with persistent symptoms despite more than three months of conservative treatment. Because some participants had only one affected wrist, the study included 63 wrists in total. Researchers randomly assigned each wrist to receive a saline hydrodissection procedure, a corticosteroid injection alone, or hydrodissection plus a steroid shot.

All three treatments initially improved symptoms, but by six months, the benefits of the corticosteroid injection alone had worn off. Average pain scores in the hydrodissection group had fallen from about 4.6 to 0.5 on a 10-point scale. Pain in the steroid-only group, by contrast, had returned to its pretreatment level.

Nearly 86 percent of wrists treated with saline hydrodissection had a clinically meaningful improvement in symptom severity at six months. Adding corticosteroids to hydrodissection didn’t significantly improve the results.

“It actually came as a pleasant surprise that hydrodissection with saline alone gave marked relief in carpal tunnel syndrome, which lasted for six months,” Dr. Tandon says.

The results may also offer a clue about how hydrodissection works. “It indicates that the primary relief was due to mechanical separation of the nerve from surrounding adhesions rather than the drug effects,” Tandon adds.

Who Should Consider Hydrodissection for Carpal Tunnel Treatment?

Bollier says hydrodissection could be a reasonable nonsurgical option for people with less severe carpal tunnel syndrome. The best candidates are likely those who don’t have constant numbness, hand weakness, or muscle atrophy, he adds.

“Surgical release of the tight carpal tunnel is still the gold standard, because it is the most powerful way to decrease pressure on the nerve long-term by allowing more space for the nerve,” Bollier says. “Ultrasound-guided hydrodissection is a reasonable non-operative approach to try for carpal tunnel syndrome, but some patients may still need carpal tunnel release surgically.”

The study did not compare hydrodissection with surgery, so it cannot show whether the procedure is as effective as carpal tunnel release or whether it prevents people from eventually needing surgery.

More Research Is Needed

“I would call this an important proof-of-concept study rather than definitive evidence,” Mathieu says. “I would particularly like to know whether the benefit is still present after one or two years, and how many patients ultimately required additional treatment or surgery.”

The procedure was also performed by a musculoskeletal radiologist with more than 20 years of experience, so it’s unclear whether similar results would be seen in other settings. “Larger multicenter studies involving different clinicians and longer follow-up will be important to determine how reproducible and durable these results are,” Dr. Thornton says.

Hydrodissection is already performed in the United States, Thornton says, although availability varies and techniques aren’t yet standardized.

“Patients interested in the procedure should look for a physician with specific experience performing ultrasound-guided nerve procedures rather than assuming that experience with general musculoskeletal injections is equivalent,” Thornton says.