Typing with numb fingers, having trouble holding a pen, or waking up with a sore hand can make daily life exhausting for people with carpal tunnel syndrome.
The disease develops when a nerve supplying the hand becomes trapped in a narrow passage in the wrist. Pressure can disrupt nerve signals, causing pain, tingling, numbness and weakness.
Now a small trial has found that injecting saline around the trapped nerve can relieve symptoms for longer than a steroid injection.
The relief persisted for six months after the saline procedure, by which time the initial benefits of the steroid injection alone had largely worn off.
Saline is used to open the space between tissues. In this procedure called hydrodissection, a clinician uses ultrasound to guide a thin needle along the nerve. The sterile saline solution is injected around him, separating him from the tissues that restrict his movements.
This aims to help the nerve move more freely. A steroid injection relieves symptoms by reducing inflammation and swelling.
“This relieves pressure on the nerve and improves patients’ symptoms,” radiologist Anupama Tandon, from the University College of Medical Sciences and Guru Teg Bahadur Hospital in India, told ScienceAlert.
The researchers wanted to determine the benefits of tissue separation. Most previous hydrodissection studies included drugs in the injected fluid, so it was difficult to say whether the procedure or the drug deserved this credit.
Led by radiologist Anindita Bose of Mahatma Gandhi Medical College and Hospital, the team studied 39 adults whose symptoms persisted for more than three months, despite treatments such as medication or wrist splints.
Some suffered from this disease in both hands, so the trial included 63 wrists.
Each wrist was randomly assigned to one of three treatments. One group received hydrodissection with saline alone. Another received a steroid injection without a tissue separation procedure. The third received a hydrodissection with a steroid added to the saline solution.
All treatments were guided by ultrasound. Injections containing steroids also included a local anesthetic. The researchers then tracked the progression of pain, numbness and difficulty using the hand, with ultrasounds checking for nerve swelling over the first three months.
All three treatments helped at first. The difference became apparent over the following months: pain returned in the steroid-only group, while relief continued in the saline-only hydrodissection group.
Adding steroids to hydrodissection did not clearly improve results.
Ultrasound images supported the patients’ reports. Nerve swelling decreased more in both hydrodissection groups than in the group receiving steroid injections only.
These findings support the researchers’ explanation that separating the nerve from surrounding tissue contributes to relief. However, the trial did not include any groups that received a sham injection, so the contribution of patients’ treatment expectations could not be assessed separately.
Tandon described a young typist whose pain and numbness had become so disruptive that her job was threatened. Medication and a wrist brace failed to help.
“After the hydrodissection, her symptoms improved and she was able to return to work,” Tandon said.
The treatment lasted approximately 15 minutes and did not require any hospitalization. No major complications were observed. Some participants experienced mild pain and swelling that resolved within a few days. One person experienced tingling during needle placement, with no lasting neurological effects reported.
Larger studies are needed to establish the reliability of the procedure and the duration of relief. This trial involved a small number of people in one center, with follow-up ending at six months. She did not directly compare hydrodissection to surgery.
“It is beneficial for mild to moderate carpal tunnel syndrome,” Tandon said, “while severe cases require surgery.”
The team began a longer study comparing saline solution to dextrose, a type of sugar, to determine which liquid provided longer-lasting relief.
The research was published in Radiology.
This article was fact-checked by Peter Dockrill and edited by Peter Dockrill. Although we are proud of our process, we are only human. If you spot an error, please let us know.
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