Sonographic follow-up of patients with carpal tunnel syndrome undergoing surgical or nonsurgical treatment: prospective cohort study.

PURPOSE: To compare changes in the largest cross-sectional area (CSA) of the median nerve in wrists undergoing surgical decompression with changes in wrists undergoing non-surgical treatment of carpal tunnel syndrome (CTS). METHODS: This study was a prospective cohort study in 55 consecutive patients with 78 wrists with established CTS, including 60 wrists treated with surgical decompression and 18 wrists with non-surgical treatment. A sonographic examination was scheduled before and 4 months after initiation of treatment. We compared changes in CSA of the median nerve between wrists with surgical treatment and wrists with non-surgical treatment using linear regression models. RESULTS: Decreases in CSA of the median nerve were more pronounced in wrists with CTS release than in wrists undergoing nonsurgical treatment (difference in means, 1.0 mm(2); 95% confidence interval, 0.3-1.8 mm(2)). Results were robust to the adjustment for age, gender, and neurological severity at baseline. Among wrists with CTS release, those with postoperative CSA of 10 mm(2) or less tended to have better clinical outcomes than those with postoperative CSA of greater than 10 mm(2) (p=.055). Postoperative sonographic workup in the 3 patients with unfavorable outcome or recurrence identified likely causes for treatment failure in 2 patients. CONCLUSIONS: In this observational study, surgical decompression was associated with a greater decrease in median nerve CSA than was nonsurgical treatment. Smaller postoperative CSAs may be associated with better clinical outcomes. Additional randomized trials are necessary to determine the optimal treatment strategy in different subgroups of patients with CTS. TYPE OF STUDY/LEVEL OF EVIDENCE: Therapeutic III.