The comparison of the effectiveness between different doses of local methylprednisolone injection versus triamcinolone in Carpal Tunnel Syndrome: a double-blind clinical trial

PURPOSE: Local corticosteroid injection is one of the most prevalent methods in treating carpal tunnel syndrome (CTS). However, the most efficient substance and its appropriate dosage remain controversial. In the present double-blind randomized controlled trial, the efficacy and safety of local injection of two corticosteroids (triamcinolone and methylprednisolone) were compared at two different dosages, 20 and 40 mg. PATIENTS AND METHODS: We consecutively included 80 patients with mild or moderate CTS and randomly assigned them to four groups: 20 or 40 mg triamcinolone (T20 or T40) and 20 or 40 mg methylprednisolone (M20 or M40) groups; each patient received a single injection of steroid using conventional approach. The four groups were relatively comparable and did not show any significant difference initially in their baseline measurements including pain intensity measured using VAS, pain-free grip strength (PFGS), nerve conduction study (NCS), and two parts of Boston Carpal Tunnel Syndrome Questionnaire: symptom severity scale (SSS) and functional status scale (FSS); the latter was our primary outcome measure. Three months after injection, they were reassessed to evaluate the clinical and electrodiagnostic changes. RESULTS: Almost all NCS parameters, VAS, and PFGS significantly improved after treatment in all the groups (P<0.05). Compound motor action potential amplitude significantly improved only in T40 group (P=0.032), while there was no significant improvement in other groups. Furthermore, SSS remarkably decreased in all the four groups, without any significant difference between the groups (P=0.87). A similar significant decrease was found in FSS, with a higher improvement in T40 group (P=0.009). There was no significant difference between the four groups in other variables after treatment. CONCLUSION: Based on the current data, the efficacy and safety of local injection of triamcinolone and methylprednisolone at doses of 20 and 40 mg were associated with a significant improvement in pain, functional status, and strength. Although, there was no remarkable superiority, 40 mg injection, especially for triamcinolone, yielded better NCS results and functional status