Babol University of Medical Sciences Caspian Journal of Surgery 3115-9087 Articles in Press 2026 04 28 Effectiveness of Ultrasound-Guided Median Nerve Methylprednisolone Hydrodissection Vs. Open Surgery in Treatment of Carpal Tunnel Syndrome: A Parallel-Group, Single-Blinded, Randomized Clinical Trial 735314 10.22088/caspjs.2026.2079247.1054 EN Danial Hosseinzadeh Department of Orthopedics, Babol University of Medical Sciences, Babol, Iran 0000-0003-2906-7068 Parmida Abdavi Student Research Committee, School of Medicine, Babol University of Medical Sciences, Babol, Iran 0000-0002-6684-4703 Payam Ghafouri Department of Physical Therapy, School of Rehabilitation, Tehran University of Medical Sciences, Tehran, Iran 0009-0008-5470-2135 Mehrafza Mir Department of Anesthesiology, School of Medicine, Babol University of Medical Sciences, Babol, Iran 0000-0001-6356-7117 Amirhossein Zohrehvand Department of Neurosurgery, School of Medicine, Babol University of Medical Sciences, Babol, Iran 0000-0002-9441-2107 Journal Article 2026 04 21 Background: Carpal tunnel syndrome (CTS) is one of the most prevalent entrapment neuropathies of the upper extremity. Hydrodissection, a technique guided by ultrasound, has gained increased interest in the last decade for managing entrapment neuropathies. However, the comparison of ultrasound-guided hydrodissection versus open surgery for the treatment of CTS remains challenging due to uncertainty in current findings from limited studies. This trial compared the effects on function and severity of ultrasound-guided hydrodissection with methylprednisolone against open surgery in patients with moderate-to-severe CTS.<br /> Methods: In this randomized parallel-group, single-blinded clinical trial, 46 patients with CTS aged 20 to 65 were randomly allocated to either hydrodissection (injection of methylprednisolone, n=23) or open surgery (n=23) group. The functional status and severity scores of the Boston Carpal Tunnel Questionnaire (BCTQ) were the primary outcome and were assessed at baseline and one and three months after each intervention. <br /> Results: 44 patients, with a mean age of 48±10.3, successfully completed the study. Adjusting for baseline outcomes, the mixed model ANCOVA did not reveal significant Group*Time interactions for either severity (F=1.006; P=0.330; ηp2 =0.056) nor function (F=0.856; P=0.368; ηp2 =0.048) scales of the BCTQ. Both groups experienced similar improvements in both severity (one month: Δ0.1, 95%CI -0.4 to 0.6; three months: Δ0.4, 95%CI -0.25 to 1.05) and function (one month: Δ0.25, 95%CI -0.3 to 0.8; three months: Δ0.5, 95%CI -0.2 to 1.2) outcomes.<br /> Conclusions: This clinical trial showed that ultrasound-guided methylprednisolone hydrodissection and open surgery were similarly effective in moderate-to-severe CTS patients in the short term.