Steroid shots can temporarily relieve the painful symptoms of carpal tunnel syndrome, but three-quarters of patients who are initially helped by these injections will eventually require surgery, new Swedish research says.
About 5% of Americans suffer from carpal tunnel syndrome, which occurs due to pressure on a key nerve that runs from the forearm into the palm of the hand. It is a repetitive-motion injury that tends to affect people performing assembly line or data entry work.
The median nerve is housed within the tight confines of the carpal tunnel, a narrow corridor of ligament and bones at the base of the hand. Tendons located in the carpal tunnel can swell and squeeze the median nerve if they become irritated and inflamed. Sufferers feel pain, tingling and numbness in the affected hand and wrist, with pain sometimes shooting up their arm.
Steroid shots frequently are used to reduce tendon swelling and ease pressure on the nerve, said Dr David Ruch, chief of orthopaedic hand service at the Duke University Medical Center and practice division director for the American Society for Surgery of the Hand. Mild cases can be treated with splints worn to keep the wrists straight until swelling inside the carpal tunnel goes down.
However, surgery to open up the carpal tunnel and relieve pressure on the nerve remains the most effective treatment for moderate to severe cases, so much so that carpal tunnel release is one of the most common surgical procedures in the United States, according to the US National Institute of Neurological Disorders and Stroke.
The new study affirms the common perception among doctors that steroid shots serve as only a temporary fix for patients with moderate or severe cases of carpal tunnel syndrome, Ruch said.
"The long-term ability of carpal tunnel syndrome to be treated with an injection is really based upon the severity of your symptoms, how long the symptoms have been in place and how old you are," he said.
The new research, from doctors at Hassleholm Hospital in Sweden and published in the September 3 issue of the journal Annals of Internal Medicine, involved 111 patients aged 18 to 70 with carpal tunnel syndrome who had no previous steroid injections. Doctors treated two-thirds of the patients with injections of methylprednisolone, a type of steroid.
Within 10 weeks, people who received steroid injections were less likely to report pain, numbness, tingling or other symptoms.
Three out of four patients who received steroids, however, needed surgery within one year.
Those most likely to benefit from steroid shots are people under 30 with mild symptoms and less pressure on their median nerve. "You have a reasonable chance of having your symptoms go away and stay gone with the cortisone shot," Ruch said.
But steroid shots will improve symptoms for only about six months in people over 35 who have moderate to severe carpal tunnel syndrome, he said.
First line treatment
Despite these findings, doctors will continue to use steroid shots as a first-line treatment for carpal tunnel syndrome, said Dr Leon Benson, of the Illinois Bone & Joint Institute in Glenview, Illinois.
Steroid shots help doctors rule out other potential causes for the symptoms patients are experiencing. If the steroid shots don't work, then the patient probably has something other than carpal tunnel syndrome.
"Injection is a crucial and important part of treating patients with carpal tunnel syndrome initially, because it helps confirm the diagnosis," Benson said. "I never operate on anyone unless I've given them a steroid injection first."
The patient's response to a steroid injection also serves as a good prediction for how well they'll respond to surgery, Ruch added.
"It does a very nice job of delineating who is going to have a good response to surgery," he said. "If you had good relief from your cortisone shot, chances are very, very high you're going to get good results from surgery."
To avoid carpal tunnel syndrome, you can:
- Perform stretching exercises on your wrists.
- Take frequent breaks.
- Wear splints or braces to keep your wrists straight.
- Ask your employer to rotate your job or perform an ergonomic assessment of your work space.
For more information on carpal tunnel syndrome, visit the National Institute of Neurological Disorders and Stroke.