Efficacy of Ultrasound-Guided Hydrodissection in Carpal Tunnel Syndrome

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.

The median nerve will be defined at the proximal entrance of the carpal tunnel (scaphoid-pisiform plane). Under the ulnar approach with the in-plane technique, it was planned to hydrodissect the median nerve using 5 cc of 5% dextrose.

The median nerve will be defined at the proximal entrance of the carpal tunnel (scaphoid-pisiform plane). Under the ulnar approach with the in-plane technique, it was planned to hydrodissect the median nerve , using 5 cc normal saline.

The median nerve will be defined at the proximal entrance of the carpal tunnel (scaphoid-pisiform plane). Under the ulnar approach with the in-plane technique, it was planned to hydrodissect the median nerve , using 10 cc 5% dextrose.

The median nerve will be defined at the proximal entrance of the carpal tunnel (scaphoid-pisiform plane). Under the ulnar approach with the in-plane technique, it was planned to hydrodissect the median nerve from , using 10 cc normal saline.

The median nerve will be defined at the proximal entrance of the carpal tunnel (scaphoid-pisiform plane). Under the ulnar approach with the in-plane technique, first it was planned to hydrodissect the median nerve from the retinaculum superiorly and then from the flexor tendons inferiorly, using 5 cc of 5% dextrose.

The median nerve will be defined at the proximal entrance of the carpal tunnel (scaphoid-pisiform plane). Under the ulnar approach with the in-plane technique, first it was planned to hydrodissect the median nerve from the retinaculum superiorly and then from the flexor tendons inferiorly, using 5 cc normal saline.

The median nerve will be defined at the proximal entrance of the carpal tunnel (scaphoid-pisiform plane). Under the ulnar approach with the in-plane technique, first it was planned to hydrodissect the median nerve from the retinaculum superiorly and then from the flexor tendons inferiorly, using 10 cc 5% dextrose.

The median nerve will be defined at the proximal entrance of the carpal tunnel (scaphoid-pisiform plane). Under the ulnar approach with the in-plane technique, first it was planned to hydrodissect the median nerve from the retinaculum superiorly and then from the flexor tendons inferiorly, using 10 cc normal saline.

Pain intensity was measured with visual analogue scale for pain (0-10 mm; 0 means no pain, 10 means severe pain) which is used to measure musculoskeletal pain with very good reliability and validity.

The Boston Carpal Tunnel Syndrome Questionnaire (BCTQ) is a frequently used questionnaire for CTS that includes 2 components. It evaluates for grading under two sub-headings: symptom severity scale (11 questions) and functional status scale (8 questions). Scores range from 0 to 5 for each question; 0 represents no difficulty during the activity, 5 represents extremely severe dysfunction.

The cross-sectional area (CSA) of the median nerve will be used for analysis by the mean value of 3 measurements made with an electronic caliper at the same level as the injection site (scaphoid-pisiform level). CSA values increase as clinical findings worsen.

Antidromic sensory nerve conduction velocity and distal motor latency of the median nerve will be measured in all patients. All measurements will be made 3 times and the average value will be taken. To diagnose CTS electrophysiologically; The median nerve peak sensory conduction velocity recorded antidromically from the second finger should be slower than 41.25 m/sec, the conduction velocity should be slower than 34 m/sec in the mixed nerve conduction study in the palm-wrist segment (8 cm), and/or recordings from the APB (abductor pollicis brevis) muscle DML (distal motor latency) was determined to be longer than 3.8 ms with stimulation of the median nerve from the wrist segment (5 cm).

The hand grip strength of the participants will be measured with the "Jamar Hand Dynamometer". Measurements will be made with the shoulder in adduction and neutral rotation adjacent to the trunk, elbow 90 degrees flexed, wrist 0-30 degrees dorsiflexion and 0-15 degrees ulnar deviation with thumb up. Finger grip strength will be evaluated with the "Jamar Digital Pinchmeter". Patients will be placed in the sitting position with the wrist in 90° flexion and the forearm in the neutral position. Measurements will be made bilaterally in three different positions as lateral, palmar and fingertip grips. Patients will be asked to squeeze with maximum force and each measurement will be made three times, and their averages will be recorded in kg. The dynamometer has a dual scale readout which displays isometric grip force from 0-90 kg. Higher scores means better grip strength.

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

Babaei-Ghazani A, Forogh B, Raissi GR, Ahadi T, Eftekharsadat B, Yousefi N, Rahimi-Dehgolan S, Moradi K. Ultrasound-Guided Corticosteroid Injection in Carpal Tunnel Syndrome: Comparison Between Radial and Ulnar Approaches. J Pain Res. 2020 Jun 26;13:1569-1578. doi: 10.2147/JPR.S248600. eCollection 2020.

Chang KV, Wu WT, Ozcakar L. Ultrasound imaging and guidance in peripheral nerve entrapment: hydrodissection highlighted. Pain Manag. 2020 Mar;10(2):97-106. doi: 10.2217/pmt-2019-0056. Epub 2020 Mar 12.

Lam KHS, Hung CY, Chiang YP, Onishi K, Su DCJ, Clark TB, Reeves KD. Ultrasound-Guided Nerve Hydrodissection for Pain Management: Rationale, Methods, Current Literature, and Theoretical Mechanisms. J Pain Res. 2020 Aug 4;13:1957-1968. doi: 10.2147/JPR.S247208. eCollection 2020.