By Kathryn Doyle
NEW YORK (Reuters Health) - Steroid shots for carpal tunnel syndrome may help some sufferers in the short term, but most people end up having surgery whether or not they get the shots, according to a small new study.
Researchers in Sweden found that one year after diagnosis, three quarters of carpal tunnel patients who tried steroid shots and other treatments first had opted for surgery while more than 90 percent of those who did not get the shots had the surgery.
"We did not know how effective steroid injections are so we were not expecting any particular result," said lead author Dr. Isam Atroshi of Hässleholm Hospital.
According to this study, steroids usually don't help enough to avoid surgery, which is "somewhat surprising" since many doctors routinely order the shots, Atroshi told Reuters Health.
It's estimated that one in 20 adults in the U.S. will experience carpal tunnel syndrome, as a result of pressure on the median nerve that runs from the arm into the hand, through the so-called carpal tunnel formed by bones and ligaments of the wrist.
If ligaments forming the tunnel, or tendons that also run through the tunnel, become swollen, pressure on the nerve can cause tingling, weakness or pain in the wrist and hand.
The condition, which can affect one or both hands, is initially treated with wrist splints, then if rest doesn't bring improvement, with steroid shots.
When neither splints nor steroids seem to help, the next step is surgery, an effective but costly remedy.
Atroshi and his coauthors gave injections of 80 milligrams methylprednisolone, or 40 milligrams of the steroid or a dummy shot to 111 carpal tunnel syndrome patients between 18 and 70 years old who had already tried wrist braces with no luck.
Ten weeks later, patients who had received the steroids were less likely to report pain, numbness or tingling than those who got a placebo.
At the one-year mark, however, 73 percent of the patients who got the 80 mg steroid shots had the surgery, as did 81 percent of patients who got the lower steroid dose and 92 percent of those who had a placebo shot.
Though patients who got the highest dose of steroids were less likely to have surgery by one year, there were no differences between the three groups in reported pain at that point, according to the results published in the Annals of Internal Medicine.
Complications are unlikely with either treatment, Atroshi said.
"Surgery is effective because, by dividing the ligament that forms the roof of the tunnel, or ‘opening' the carpal tunnel, there will be a rapid dramatic decrease in the pressure and symptom relief, and the effect is usually durable," he said.
The cause of carpal tunnel syndrome is not completely known, but it's not surprising that surgery is more effective than shots, according to Dr. Charles Leinberry, a hand surgeon at the Rothman Institute in Philadelphia.
Steroids temporarily reduce local swelling and relieve pressure in the tunnel, but surgery actually makes the tunnel bigger and is a permanent solution, said Leinberry, who was not involved in the study.
"Surgery adds approximately 25 percent to the volume of the carpal tunnel area and provides more room for the tendons and nerves present in the tunnel," he said.
Experts didn't think the new study's results would change the way carpal tunnel syndrome is treated.
Most doctors first recommend splints, which can be very effective when used early, and take a medical image of the wrists to determine how severe the diseases is, Leinberry said.
Steroids can help control pain for a short while if the disease is not severe, but can probably be skipped if the carpal tunnel syndrome is severe and requires surgery, he said.
Dr. José Luis Andreu, a rheumatologist at Hospital Universitario Puerta de Hierro Majadahonda in Madrid, published a similar study in 2005 that found only 42 percent of patients who had received steroid shots ended up getting surgery. In his study, the patients could have a second shot if the first failed, and researchers used triamcinolone, a different steroid.
Steroids can be safe and effective, and are much simpler than surgery, but patients with moderate to severe carpal tunnel should be treated with surgery, he said.
In the U.S., doctors may charge up to $500 to administer a single steroid shot, while carpal tunnel surgery done on an outpatient basis can run $3,000 or more.
"You should consider that a proportion of patients will need surgery after the injection because of lack of adequate response, but a proportion of patients will not need surgery and a lot of time and money will be saved," Andreu told Reuters Health by email.
Surgery is always more expensive than steroid injections, "however surgery is usually a permanent solution and therefore in the long run is more cost effective since it provides a cure," Leinberry said.
SOURCE: http://bit.ly/15wpbjP Annals of Internal Medicine, online September 3, 2013.