Oct. 15, 1999 (New York) -- Injecting steroid drugs near -- but not in -- the carpal tunnel of the wrist can lead to a long-term improvement of symptoms in people with carpal tunnel syndrome, according to Dutch researchers. They conclude that the therapy should be considered as an option before surgery in people with the repetitive motion injury. Among patients with carpal tunnel syndrome who received a single injection of steroids, 77% had improvement in symptoms at one month and 50% continued to benefit one year later. The report is published in a recent issue of the British Medical Journal.
Injection of the steroid drug methylprednisolone into the carpal tunnel is one recommended treatment for carpal tunnel syndrome. However, this method is associated with complications such as infection and nerve damage. In some studies, this method also has been associated with a short duration of benefit. The authors of the new study say injecting the drug near the carpal tunnel reduces the risk of complications and is technically easier to perform than injection into the narrow carpal tunnel itself.
Carpal tunnel syndrome is caused by compression of the median nerve that runs through the carpal tunnel in the wrist. People with carpal tunnel syndrome typically have pain, weakness, and numbness or tingling in the hand and arm. The syndrome is generally thought to be caused by repetitive motion such as typing, operating equipment, or any type of work that requires chronic repetitive motion of the fingers, wrist, and arm.
J.W.H.H. Dammers, MD, and colleagues from the Academic Medical Center at the University of Amsterdam studied 60 patients who each had a three-month or longer history of carpal tunnel syndrome. Patients were divided into two groups: control and intervention. People in the control group received an injection of the anesthetic lidocaine and people in the invention group received lidocaine plus methylprednisolone. The injections were given in the forearm about 4 cm from the wrist crease. Following the injection, the fluid was gently massaged toward the carpal tunnel area.
At one month, 77% of patients in the intervention group had few or no symptoms, compared with only 20% of patients in the control group. Twenty-eight patients in the control group were subsequently offered the steroid injection and of these, 86% responded to treatment. However, half of those who responded to treatment did eventually require carpal tunnel surgery.
None of the patients experienced side effects, and the authors say the duration of benefit seen in patients who initially received methylprednisolone is longer than previously reported.
However, an expert who reviewed the study for WebMD says that although the authors conclude that the results are better than what has previously been reported, multiple studies indicate that in the long term, regardless of whether the injection is in or near the carpal tunnel, steroid injection is not a permanent solution since less than 10% of patients sustain benefits from a single steroid injection. "A lot of people have improvement with cortisone but it doesn't resolve anything," says Michelle Gerwin Carlson, MD.
"Yes, they will get temporary improvement, but it doesn't get rid of the problem and in almost all people, the improvement seen after the injection eventually goes away. To answer this question about long-term benefit you would need hundreds of patients, not 60. But overall, the number of people who can be cured with cortisone is very, very small." Carlson is an orthopedic and hand surgeon at the Hospital for Special Surgery in New York. She is also an assistant professor at the New York Hospital-Cornell Medical Center.
She adds that the swelling near the carpal tunnel that the researchers describe is unusual in patients with carpal tunnel syndrome and may have been a sign of tendonitis, a condition in which the tendons become inflamed as a result of injury. "If tendonitis is the problem, the injection can cure the tendonitis and as long as you don't revamp the tendonitis, you may be cured and that may be what happened in these patients. But most people with carpal tunnel don't have much swelling. The hand feels swollen from the pressure, but we don't usually see patients with noticeable swelling."