Evaluating degree of symptom improvement, safety and the change of electrophysiological findings after ultrasound versus landmark guided steroid injection in treatment of carpal tunnel syndrome

Abstract

To evaluate the degree of symptom improvement, safety and the change of electrophysiological findings after ultrasound (US)-guided versus landmark (LM)-guided local steroid injection in treatment of carpal tunnel syndrome (CTS). Fifty-two patients with moderate or moderate to severe CTS were recruited in this study. The subjects were randomly assigned into each US-guided or LM-guided steroid injection group and received 40 mg methylprednisolone. After 4 weeks and 12 weeks, the patients were evaluated using Boston questionnaire and electrophysiologic parameters. All variables including symptom/functional scores and electrophysiological findings improved significantly in both groups after 4 weeks (all P < 0.05) except CMAP amplitude in LM-guided group. However, LM-guided group showed a regress with all variables after the 12-week period compared with the 4-week period, these improvements persisted at the week 12 after treatment in the US-guided group ( P < 0.05) except Functional Status Scale (FSS) and Sensory Nerve Action Potential (SNAP). The improvement in the Compound Muscle Action Potential (CMAP) amplitude in the US-guided group at the week 12 was higher than in the LM-guided group ( P < 0.05); however, SNAP amplitude and SNAP Nerve Conduction Velocity (NCV) had improved significantly in the LM-guided group. Significant differences were not observed between groups with respect to Symptom Severity Score (SSS), FSS, SNAP latency, and CMAP latency in 4 or 12 weeks after treatment ( P > 0.05). symptom severity, functional status and all electrophysiologic parameters improved significantly in both groups and generally no statistical significant difference was observed between two groups.