The effectiveness of triamcinolone acetonide vs. procaine hydrochloride injection in the management of carpal tunnel syndrome: a double-blind randomized clinical trial.

Objective: Corticosteroid injection into the carpal tunnel is frequently used for the treatment of carpal tunnel syndrome (CTS). Steroids are usually mixed with local anesthetics, which have positive effects that can aid the treatment of CTS by inhibiting the spontaneous discharge ability of excitable cells. The aim of this study was 3-fold: (1) to determine the efficacy of triamcinolone acetonide injection in the treatment of CTS, (2) to determine the efficacy of procaine hydrochloride (HCl) in the treatment of CTS, and (3) to compare the efficacy of triamcinolone acetonide and that of procaine HCl in the treatment of CTS.

Design: This prospective, randomized, double-blind clinical trial included 99 patients (120 median nerves) with clinical and electrophysiologic evidence of CTS. The 120 median nerves were randomly assigned to one of three groups: group 1 received 40 mg of triamcinolone acetonide, group 2 received 4 ml of 1% procaine HCl, and group 3 received both 40 mg of triamcinolone acetonide and 4 ml of 1% procaine HCl. Clinical and electrophysiologic evaluations were performed at the study onset and at 2 and 6 mos after treatment.

Results: At the study onset, there were no statistically significant differences between the groups with respect to distal motor latency, compound motor action potential, compound sensory action potential, sensory nerve conduction velocity, or visual analog scale score; however, distal motor latency, compound sensory action potential amplitude, sensory nerve conduction velocity, and visual analog scale scores improved significantly in each group 2 mos after treatment (P < 0.05), and these improvements persisted at 6 mos after treatment (P < 0.05). Significant differences were not observed between groups 1 and 2 or between groups 1 and 3 with respect to electrophysiologic findings at baseline or 2 or 6 mos after treatment (P > 0.05). Group 3 had better compound sensory action potential amplitude and sensory nerve conduction velocity scores than group 2 did at 6 mos (P < 0.05) and better visual analog scale scores than group 2 did at 2 and 6 mos (P < 0.05).

Conclusions: Local procaine HCl injection and steroid injection effectively reduced the symptoms of CTS and equally improved electrophysiologic findings. As such, procaine HCl can be used in CTS patients in whom steroid use is contraindicated.