Comparing the Efficacy of Local Triamcinolone Injection in Carpal Tunnel Syndrome Using Three Different Approaches with or without Ultrasound Guidance [Letter]

Dear editor

We read the article by Rayegani et al with great interest.¹ In their study, the authors compared three methods (landmark-guided, conventional ultrasound-guided midline approach and ultrasound-guided ulnar in-plane method) in the treatment of carpal tunnel syndrome (CTS) and found that all of these three methods could improve pain intensity, function and electrophysiologic and radiographic outcomes. In addition, no statistical differences were found among the three groups in any outcomes.

However, the unreasonable P values in the study should be noted. In Table 2, five P values were greater than 0.05.¹ For example, the P value in the ulnar in-plane group regarding Boston questionnaire symptom severity scale (BQ-SSS) was 0.542, meaning no significant difference was found in symptom severity before and after ultrasound-guided ulnar in-plane triamcinolone injection. But according to our clinical and statistical experience, nearly 50% improvement showed a non-significant difference was inconceivable. Meanwhile, previous studies all showed statistical improvements in BQ-SSS after ultrasound-guided corticosteroid injection treatment.^2–5 Considering the authors used paired t-test through SPSS software in the study, P values in the Paired Samples Correlations and in the Paired Samples Test could be confused in the output document if not careful, so the P values in the Paired Samples Correlations may be recorded as original P values in the Paired Samples Test.

Hence, we advise the authors recalculate the data in this part. If all the P values in Table 2 were less than 0.05, the “Discussion” and “Conclusion” section should be corrected appropriately.