A few studies have shown that the mini-incision release technique decreases the pathologic swelling of the median nerve at the inlet of the carpal tunnel and increases the flattening ratio of the median nerve in the carpal tunnel. However, it is unknown whether the endoscopic release technique similarly reverses these pathological changes in the median nerve along the carpal tunnel in patients with CTS compared with the mini-incision release.

Investigators therefore conducted the current study to compare the subjective outcomes and US-measured morphological changes in the median nerve in patients with CTS who received either mini-incision or endoscopic release. Investigators hypothesized that (1) subjective outcomes, as assessed by both the Boston Carpal Tunnel Questionnaire (BCTQ) symptom/function scores and the DASH scores, would be similar 24 weeks after either mini-incision or endoscopic carpal tunnel release; (2) changes in the morphology of the median nerve at each level of the carpal tunnel, as measured under high-resolution US, would be similar 24 weeks after either mini-incision or endoscopic carpal tunnel release; and (3) morphological changes would be correlated with improvements in subjective outcomes 24 weeks after mini-incision or endoscopic carpal tunnel release.

Inclusion Criteria:

• Patients who are 20 years or older.
• Patients with idiopathic CTS that was confirmed by electrodiagnostic tests
• Patients with idiopathic CTS who were scheduled for carpal tunnel release

Exclusion Criteria:

• Patients with a history of wrist-area fracture or dislocation
• Patients with previous carpal tunnel release
• Patients with associated cervical radiculopathy, cubital tunnel syndrome, thoracic outlet syndrome, diabetes mellitus, hypothyroidism, arthritis, or Burger's disease
• Patients with cognitive impairment that affected the patient's ability to complete the questionnaires
• Patients with worker's compensation issues
• Patients with inadequate follow-up (i.e., less than 24 weeks post-operation)