The aim of our study is to determine the effectiveness of US-guided hydrodissection of the median nerve in different contents and volumes in patients diagnosed with mild to moderate carpal tunnel syndrome.

Carpal tunnel syndrome is the most common form of entrapment neuropathies. Anatomically, the roof of the carpal tunnel consists of carpal bones, it is located under the transverse carpal ligament, and there are 9 tendon packs of the forearm flexors and the median nerve. Clinically, sensory (paresthesia and hypoesthesia), motor deficits and pain occur in the distribution of the median nerve secondary to mechanical compression and local ischemia.

Conservative treatment options are available for patients diagnosed with mild and moderate CTS as a result of CTS classification. Treatment options for symptom relief include physical therapy applications, splinting, and wrist injections. Among local injection treatments; applications such as corticosteroids and local anesthetics are included.

Ultrasound-guided injections of peripheral nerves are generally superior to blind injections as they prevent damage to critical vascular structures in the surrounding tissue accompanying the nerves and reduce the risk of intraneural injections.

Ultrasound (US) guided hydrodissection of peripheral nerves (HD) is a technique that uses high-resolution ultrasound-guided fluid injection to separate nerves from a surrounding or adjacent structure, usually fascia. The aim is to restore function to the nerve and to release soft tissue adhesions that cause entrapment.

This investigation was designed double-blind prospective randomized study. Participants were randomized into 4 groups: Ultrasound-guided Hydrodissection (HD) with 5 cc 5% dextrose, Ultrasound-guided Hydrodissection (HD) with 5 cc normal saline, Ultrasound-guided Hydrodissection (HD) with 10 cc 5% dextrose, Ultrasound-guided Hydrodissection (HD) with 10 cc normal saline.

Ultrasonographic evaluation and ultrasound-guided injection were planned to be performed with the 10-18-MHz linear probe of the MyLab 70 (Esaote, Genova, Italy) device by a physician experienced in US. It was designed in such a way that the physician was blind to the clinical information of the patients and the injected material.

As evaluation parameters, Visual Analogue Scale (VAS), Boston Carpal Tunnel Syndrome Questionnaire (BCTQ), Cross-sectional Area of Median Nerve (CSA), Hand and finger grip strength assessment, and Electrophysiological assessment will be evaluated. It was planned that the evaluations were made and recorded by a blinded physician to the groups at the beginning of the treatment, at the 1st month and at the 3rd month controls.

Inclusion Criteria:

• Presence of symptoms of carpal tunnel syndrome, including nocturnal, postural, or movement-related paresthesias +/- pain in the median nerve distribution area in the hand for more than 3 months
• Presence of mild to moderate carpal tunnel syndrome proven by electrophysiological study
• Loss of sensation with numbness in the median nerve-innervated areas of the hand, weakness of the median nerve-innervated thenar muscles
• Positive Phalen test and/or Tinel sign

Exclusion Criteria:

• Patients who can mimic the diagnosis of carpal tunnel syndrome, such as cervical radiculopathy, polyneuropathy, brachial plexopathy, thoracic outlet syndrome
• Patients who have had an injection into the carpal tunnel in the last 6 months
• Patients with thenar muscle atrophy
• History of Carpal tunnel surgery
• Regular use of systemic nonsteroidal anti-inflammatory drugs and corticosteroids
• Pregnancy
• Rheumatoid arthritis, systemic lupus erythematosus, gout, systemic sclerosis, dermatomyositis, polymyositis
• Presence of malignancy
• Presence of active infection