The Effect of Exercises on the Shear Wave Velocity of the Median Nerve and the 3rd FDS in Patients With Carpal Tunnel Syndrome

The aim of the study is to evaluate the impact of exercise protocols on the US SWV of the median nerve and 3rd FDS in the carpal tunnel in participants with mild to moderate CTS. The investigators aim to establish US SWE as a potential method to monitor nerve and tendon SWE changes due to exercise intervention and consequently show the effect of different exercise interventions on mechanical changes within the carpal tunnel.

This study was conducted in accordance with the ethical principles of the Declaration of Helsinki and Good Clinical Practice guidelines. The study protocol adhered to the CONSORT guidelines for reporting randomized trials and received approval from the National Medical Ethics Committee of the Republic of Slovenia (protocol number 0120-25/2023/3). Written informed consent was obtained from all participants prior to enrolment. Participants with suspected CTS were prospectively recruited from April 2025 to October 2025 at a single tertiary referral centre: the Institute of Clinical Neurophysiology, University Medical Centre Ljubljana, Slovenia. The inclusion criteria were as follows: (1) age between 24 and 78 years; (2) affirmative responses to at least two of the following three questions: (a) tingling in at least two of the first four digits; (b) symptoms worsening at night or in the morning; (c) symptom relief with hand flicking (flick sign); and (3) electrodiagnostic (EDx) confirmation of mild to moderate median nerve entrapment neuropathy at the wrist. Exclusion criteria were: (1) previous wrist fracture or surgery; (2) polyneuropathy, motor neuron disease, cervical radiculopathy, or brachial plexopathy; (3) structural abnormalities within the carpal tunnel; and (4) tenosynovitis. The investigators conducted a prospective, randomized, three-arm, parallel-group trial with a 1:1:1 allocation ratio to Gliding, Strength, and Control groups. Outcome measures were assessed before and after the intervention. Randomization of participants into two intervention groups and one control group was performed using the Clinical Trial Randomization Tool developed by the National Cancer Institute. The same tool was applied in participants with bilateral CTS to randomly determine which hand was assessed and included in the study.

The intervention lasted for 3 weeks and was performed once daily. The control group did not participate in any training program and was instructed to continue with their usual daily and work-related activities. Ultrasound SWV measurements were performed by the primary investigator, who was blinded to participants' CTS diagnoses. A second investigator conducted the randomization process and scheduled participants' appointments; consequently, the primary investigator remained unaware of participant details prior to the SWV assessment.

Participants randomized to Gliding or Strength group received written description of exercises supported with images. Nerve and tendon gliding exercises targeted flexion and extension of the index and ring fingers, complemented by wrist flexion and extension movements. These exercises were taken from literature and designed to promote median nerve and tendon gliding through the carpal tunnel, thereby reducing entrapment of the median nerve and the 3rd FDS tendon.

Strengthening exercises involved movement patterns (finger and wrist flexion and extension) similar to the nerve and tendon gliding exercises; however, external resistance was introduced through the use of hand therapy resistance balls or low-weight dumbbells ranging from 0.5 to 2.0 kg depending on the participant.