Comprehensive Evaluation of Effect of Low Dose Local Steroid Injection in Carpal Tunnel Syndrome

Abstract

Introduction: Carpal Tunnel Syndrome (CTS) is one of the most common entrapment neuropathy with significant affection of hand function. Diagnosis is based on clinical, electrophysiological findings and ultrasonographic findings. Treatment may be nonsurgical or surgical. Of the nonsurgical methods, local glucocorticoid injection has yielded promising results in mild to moderate CTS. Use of different doses of steroid for CTS ranging from 12 mg to 40 mg with comparable results has been reported in the literature. To the best of our knowledge, efficacy of low dose steroid injection has not been evaluated in a comprehensive manner. Aim: To assess the efficacy of a low dose local steroid injection in CTS patients utilising clinical, electrophysiological and ultrasonographic parameters. Materials and Methods: Fifty five diagnosed patients of mild and moderate CTS, on the basis of electrophysiologic findings, were recruited for the study. Clinical evaluation was done in terms of grip strength and pain status. For baseline electrophysiological evaluation, nerve conduction studies were performed. This included Sensory Nerve Action Potentials (SNAPs), Sensory Distal Latency (SDL), Motor Distal Latency (MDL) and sensory and motor Conduction Velocity (CV) of median nerve as assessment parameters. Cross Sectional Area (CSA) of median nerve and bowing of flexor retinaculum was assessed using ultrasonography. Single dose of 20 mg methylprednisolone acetate was injected into the carpal tunnel under all aseptic precautions. Pain status was assessed at one week after the procedure. Overall, efficacy of the intervention was assessed using all the assessment parameters at one and three months after intervention. Statistical analysis was done using SPSS version 17 and p-value of <0.05 was considered as statistically significant. Results: 44 patients completed three months follow-up period. Most of the parameters assessed showed improvement at one month and three months after the intervention. At one month, grip strength, pain, SNAP, MDL, sensory CV and CSA of median nerve were found to be significantly improved. At three months follow-up, in addition to the further improvement in these parameters, SDL also showed significant improvement in comparison to baseline. However, motor nerve CV showed no significant improvement during the study period. Conclusion: Low dose local steroid injection is an effective intervention for treating CTS subjects. It provides rapid pain relief and improvement in objective parameters which persists till the end of three months.

Keywords

• electrophysiological assessment
• entrapment neuropathy
• methylprednisolone