<qa>  What is the difference in symptom severity score in patients who had surgery on the study hand afterThe Chi-square test will be used to compare the 80-mg methylprednisolone group and the placebo group with regard to the proportion of patients who have had carpal tunnel release surgery on the study hand within 5 years after injection primary outcome. The change in symptom severity score in patients in the 80-mg methylprednisolone group who did not have surgery on the study hand after injection will be compared with the change in symptom severity score in patients who had surgery on the study hand after methylprednisolone injection co-primary outcome using analysis of covariance ANCOVA adjusting for sex, age, dominance of the study hand and baseline symptom severity score. A similar comparison will be made for the 11-item DASH and the bodily pain scores. The palmar pain score at 5 to 7 years will be compared between the groups using the independent-samples t-test and also ANCOVA to adjust for sex, age and dominance of the study hand. Patients who had surgery after methylprednisolone injection will be compared with patients who had surgery after placebo injection with regard to change from baseline to 5 to 7 years in the symptom severity score, 11-item DASH scale score, bodily pain score and satisfaction score using ANCOVA adjusting for sex, age, dominance of the study hand and respective baseline score. To identify potential predictive factors for long-term benefit after 80 mg methylprednisolone injection, surgery within 5 years will be analyzed according to the variables sex, age, dominance of the study hand, baseline symptom severity score 3 versus 3 and baseline median nerve conduction abnormality severemoderate vs mildnormal. 