Repair of severed recurrent thenar branch of median nerve after open carpal tunnel release.

An anatomical understanding of median nerve variation is essential for successful decompression of carpal tunnel syndrome (CTS). Although iatrogenic injury of the thenar branch after carpal tunnel release (CTR) has not been reported in many cases, it can cause serious damage to the patient. In case of rapidly progressing thenar atrophy after CTS surgery, thenar branch of median nerve injury should be suspected. Nerve conduction examination and ultrasound before surgery can be a useful tool for diagnosis.