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Abstract & Commentary
Source: Wong SM, et al. Local vs. systemic corticosteroids in the treatment of carpal tunnel syndrome. Neurology 2001;56: 1565-1567.
The most frequent form of entrapment neuropathy is carpal tunnel syndrome (CTS). Patients present with median nerve paresthesias, which may progress or recur enough to interrupt sleep, dexterity, or employment. Several nonoperative therapies are available for CTS, although surgical decompression is regarded as definitive for cure. Occupational disability frequently occurs, escalating this condition to one of major clinical and economic importance.
To evaluate two conservative options for this neuropathy, Wong and colleagues studied 60 patients in Hong Kong with CTS. These patients had: 1) sensory symptoms over the median nerve distribution, 2) nerve conduction velocity (NCV) and electromyographic (EMG) studies of median and ulnar nerves that confirmed CTS by American Academy of Neurology criteria, and 3) failed splinting for two months. Cases were excluded if they had received prior steroids for CTS, had disorders associated with CTS (diabetes, rheumatoid arthritis, pregnancy, hypothyroidism), or had severe CTS requiring surgical decompression based on the presence of thenar wasting or fibrillation on EMG.
Patients were randomized to oral placebo for 10 days plus carpal tunnel injection of 15 mg of methylprednisolone, or oral prednisolone 25 mg daily for 10 days plus saline injection into the carpal tunnel. A single investigator performed all injections with opaque, taped syringes to ensure double blinding. Global symptom score (GSS) ratings from 0 (no symptoms) to 10 (severe) were determined at baseline, two weeks, eight weeks, and 12 weeks in each of five categories—paresthesia, pain, numbness, weakness, and nocturnal awakening. Average age was 50 years. Females comprised 70% of cases. Baseline GSS averaged 25.7 (maximum score: 50).
Significant advantages were observed for steroid injection over placebo at two of three assessment periods. At eight weeks, GSS was 13.7 vs. 20.8 (P = 0.002), and at 12 weeks GSS was 14.3 vs. 21.4 (P = 0.004), for steroid injection vs. placebo, respectively. At two weeks, GSS for steroid injection vs placebo was 13.6 vs. 17.8, a nonsignificant (P = 0.07) difference. Side effects were minimal. Injection pain occurred in two patients in each group, and seven patients in the oral steroid group reported bloating, polyphagia, and insomnia. The authors conclude that local steroid injection was superior to oral steroids over a three-month period in patients with mild to moderate CTS.
Comment by Michael Felz, MD
Many clinicians are familiar with splints, diuretics, non-steroidal anti-inflammatory drugs (NSAIDs), and prednisone for the management of CTS. This study by Wong and colleagues is the first published randomized, controlled study comparing steroid injection to oral therapy in a cohort of typical patients with confirmatory NCV/EMG data. Symptomatic improvement was statistically impressive at weeks eight and 12 after injection. The trend at two weeks also favored injection. Duration of injection effect persisted for 12 weeks, again with persuasive statistical significance. In contrast, oral steroid therapy was associated with steadily worsening GSS scores over time, and more side effects.
How can physicians apply these data in the ED or office? First, the clinical diagnosis of CTS is based on paresthesias of the three radial digits, sparing the 5th finger. Symptoms worsen at night. Clinical reproduction is possible by percussion over the flexor retinaculum (Tinel’s sign), extreme palmar wrist flexion (Phalen’s sign), or dorsiflexion (reverse Phalen’s). Second, management consists of splints, diuretics, and NSAIDs, with oral prednisone for poorly responsive symptoms. I am aware of two recent studies demonstrating benefit for low-dose oral prednisone (20 mg/d) for CTS.1,2 Yet recurrences are common, and some patients seek treatment in the ED due to refractory symptoms, sleepless nights, or desire for more effective medication. For such patients, ED clinicians trained in wrist injection may choose to perform steroid injection for refractory CTS, based on the data from Wong et al, or may refer patients to colleagues experienced in injection techniques. It is no longer acceptable to tell patients that oral medications, splints, and surgery are "all we have" for CTS. Injection of the wrist is in widespread use in many practices. My own experience with carpal tunnel injection spans 15 years and more than 200 cases. Patient satisfaction seems high, especially after failed attempts at splinting and medication. One executive banker phoned me days after CTS injection with methylprednisolone, so excited that he had slept through the night for the first time in months. He insisted that I inject the contralateral wrist as soon as possible. Several of my patients have returned to work or avoided CTS surgery after timely steroid injection every 3-6 months. Hence, I join Wong et al in supporting the role of steroid injection for CTS. It’s a helpful twist for the problem wrist.
1. Herskovitz S, et al. Low dose, short term oral prednisone in the treatment of carpal tunnel syndrome. Neurology 1995;45:1923-1925.
2. Chang MH, et al. Oral drug of choice in carpal tunnel syndrome. Neurology 1998;51:3909-3913.