Traditional endoscopic release directly accesses the carpal tunnel and thus carries a higher risk of nerve irritability, even nerve injury. Based on our anatomical study, the investigators developed a new endoscopic technique through a single-portal palm approach that passes superficially to palmar aponeurosis, and cut the full transverse carpal ligament. The investigators will compared the technique with the standard dual-portal endoscopic technique.

Conduct a multi-center, comparison clinical trial according to clinical Trial Reporting Standards (CONSORT). Patients in the single-portal group were treated with a single-portal palm approach that passes superficially to palmar aponeurosis and cut the full transverse carpal ligament. The comparison group were treated with Chow endoscopic technique. In order to assess efficiency of single-portal palm approach, the investigators will compared the technique with the standard dual-portal endoscopic technique. The study was approved by Shenzhen People's Hospital and informed consent was signed.

Inclusion Criteria:

• A confirmed diagnosis of carpal tunnel syndrome based on Evidence for Surgical Treatment issued by the British Society for Surgery of the Hand
• Symptoms of carpal tunnel syndrome had lasted>2 months or inadequate responses to the non-surgical treatments≥3 months
• moderate to severe symptoms.

Exclusion Criteria:

• mild symptoms or prior injuries to the extremity
• bilateral wrists involved, a combined nerve compression, gout, diabetes or chronic renal failure.