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 40mg 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.