Ultrasound-guided interventions in primary carpal tunnel syndrome: perineural injection to thread carpal tunnel release

Abstract

Carpal tunnel syndrome (CTS), the most common entrapment neuropathy, is compression of the median nerve deep to transverse carpal ligament at wrist. Ultrasonography and electrophysiological study are complementary in the diagnosis and grading of CTS in appropriate clinical settings. The initial management of patients with CTS is conservative with medical therapy and splinting. However, surgical interventions are indicated in patients in whom medical management has failed. With evolution of the concept of safe zone on ultrasonography and identification of the sonoanatomical landmarks of carpal tunnel in greater detail, Ultrasonography-guided interventions are safer and preferred over surgical management in CTS. The primary ultrasonography-guided interventions include perineural injection, perineural hydrodissection and ultrasonography-guided release of transverse carpal ligament. This review article presents the principles of ultrasonography-guided perineural injection, perineural hydrodissection in CTS, the merits and demerits of injectant used in perineural injection/ hydrodissection, and percutaneous ultrasonography-guided thread release of transverse carpal ligament utilizing the concept of safe zone of the ultrasonography-guided interventions for CTS.