Comparison of Corticosteroid Injection, Nighttime Splinting, or Their Combination for Initial Treatment of Moderate-to-Severe Carpal Tunnel Syndrome

Inclusion Criteria: 1. Patients aged no less than 18 years old with idiopathic carpal tunnel syndrome of the target side diagnosed by a specialist according to the Katz diagnostic criteria; 2. The current episode has occurred within 6 weeks without treatment before eligibility assessment, and the target side has moderate-to-severe symptoms. Exclusion Criteria: 1. Patients who have plan for surgical treatment on his or her CTS within the following 6 months; 2. Any secodary CTS caused by comorbid diseases, including rheumatoid arthritis, psoriatic arthritis, systemic lupus erythematosus, CPPD (calcium pyrophosphate dihydrate deposition disease), etc.; 3. History of fracture or surgery on the target side of the wrist; 4. Bilateral CTS with moderate or severe symptoms in both hands; 5. Received corticosteroid injections in the wrist within the past 6 months; 6. Patients who are unable to wear a splint due to trauma or other reasons; 7. Patients with clinical manifestations or electrophysiological changes indicative of significant axonal loss or denervation, including thenar muscle atrophy, sensory loss (two-point discrimination greater than 8 mm), absence of SNAP (sensory nerve action potential), absence of CMAP (compound muscle action potential) in the thenar muscles, etc.; 8. Patients who require long-term use of any form of analgesic medication, such as NSAIDs (nonsteroidal anti-inflammatory drugs), opioids, acetaminophen, etc.; 9. Patients who have used NSAIDs, opioids (e.g., tramadol), neuropathic pain medications (gabapentin, pregabalin, etc.), or oral corticosteroids within the past 2 weeks; 10. Patients who have received non-recommended wrist injection treatments (e.g., 5% glucose, platelet-rich plasma, ozone, chitosan, hyaluronic acid, etc.) within the past 6 months; 11. Patients who have undergone non-recommended physical therapies (e.g., electrotherapy, magnetotherapy, laser therapy, etc.) within the past 6 months.