Carpal Tunnel Syndrome (CTS) is the most prevalent entrapment neuropathy caused by median nerve compression in carpal tunnel characterized by nocturnal paresthesia, tingling, numbness and pain involving glove or median distribution in hand. Almost all patients are from working group of different occupations.

The non-surgical treatments are for patients having mild to moderate CTS and these include oral steroids, drugs, braces, ultrasound therapy, tendon-gliding exercises, local steroid injection or hydrodissection etc. Hydrodissection for CTS includes injecting fluid around the nerve to eliminate the adhesions, restore blood supply and improve kinematic properties of the entrapped nerve. Ultrasound (US) - guided in-plane ulnar approach for hydrodissection in the CTS is more effective \& safer. Traditionally, the steroid (triamcinolone acetonide) combined with normal saline \& lidocaine is injected for this procedure. Though, the steroid injection shows greater clinical improvement only for short term, there are also possible side effects like short-lived local pain (13%), widespread axonal \& myelin degeneration, skin thinning \& depigmentation etc. Whereas, Normal saline (NS) is an isotonic fluid which would be suitable for expanding the perineural space. There are only a few studies comparing the outcome of hydrodissection with normal saline and triamcinolone acetonide in carpal tunnel syndrome, although the steroid injection is well established in management of CTS. Therefore, this study aims to compare the outcome between normal saline alone with combination of triamcinolone, normal saline \& lidocaine. This will be a randomized clinical trial conducting in the department of Physical Medicine and Rehabilitation, Shaheed Suhrawardy Medical College Hospital, Bangladesh for 12-months period following approval of this protocol. Ethical clearance will be obtained from Ethical Review Committee (ERC) of above-mentioned hospital.

A total of 62 (sixty-two) patients above 18 years with clinical features of CTS lasting for more than 04 (four) weeks will be selected by convenience sampling and enrolled by following exclusion-inclusion criteria. All cases will be randomly assigned in to two groups (31 cases in each group) and get following treatment, i.e. Group A: Hydrodissection by 05 ml of normal saline only; Group B: Hydrodissection by 05 ml of combination of triamcinolone acetonide, normal saline \& lidocaine; Both groups: Gabapentin, Neurotropic B vitamins, static wrist splint overnight, tendon gliding exercises, maintaining Activities of Daily Living (ADL) advices. Outcome will be measured by Symptom severity scale (SSS) \& Functional status scale (FSS) of Boston Carpal Tunnel Questionnaire (BCQT), and Numeric pain rating score (NRS-11). Data will be taken before intervention (baseline) and 4th, 8th \& 12th week after intervention. The cross-sectional area of the median nerve at carpal tunnel inlet will also be measured at the baseline \& at the 12th week follow-up.

Data will be collected in a predesigned data collection sheet by face-to-face. The statistical analysis will be conducted using Statistical Package for the Social Sciences (SPSS) version 25 statistical software. The Mann-Whitney U-test and chi-square test/Fisher exact test will be used for continuous and categorical data, respectively. Intragroup data at different follow-up time-points will be evaluated using the Wilcoxon signed rank test. Differences between groups will be measured using the Mann-Whitney U-test. All statistical tests will be two-tailed, with P\<0.05 considered significant. Bonferroni correction will be performed for intergroup comparisons at different time-points. All data will be presented as mean, frequency and percentages in tables, line charts etc.