Association between Carpal Tunnel Cross-Sectional Area and Carpal Tunnel Syndrome: A Systematic Review and Meta-Analysis

Background. Carpal tunnel syndrome (CTS) is a prevalent peripheral compressive neuropathy. In addition to an enlargement of the median nerve cross-sectional area (CSA), the carpal tunnel CSA may be a determinant of CTS. However, the findings of studies assessing the association between carpal tunnel CSA and CTS are very limited and inconclusive. Purpose. The present systematic review aimed to execute a meta-analysis of present literature to establish evidence of the association between the carpal tunnel CSA at the proximal and distal levels and CTS. Methods. PICOS strategy was used to electronically search key terms in the PubMed, Cochrane Library, Embase and Wiley Online databases with no restrictions on the publication date for case-control and cohort studies. The bias risks for these studies were assessed using the Newcastle-Ottawa Scale (NOS). Meta-analysis was performed using the RevMan5 from Cochrane. A total of 13 studies comparing the association between CSA of the carpal tunnel at the proximal and distal levels and CTS between 428 CTS participants and 324 controls with a 145/249 male-to-female ratio and a mean age of 42.2 met the inclusion criteria. Results. Overall, the studies were rated as acceptable quality, having scored 4, 6, 7, or 8 (out of 9 stars) on the NOS. Meta-analysis of the included studies indicated that the overall pooled mean difference of CSA of the carpal tunnel at the proximal level was higher in the CTS groups when compared with the control groups (0.79; 95% (confidence interval) CI 0.63-0.96; p = 0.003). Similarly, the overall pooled mean difference of CSA of the carpal tunnel at the distal level was higher in CTS individuals when compared with controls (0.54; 90%CI 0.32-0.76; p = 0.32). Conclusions. This review found evidence that an increased CSA of the carpal tunnel at the proximal and distal levels is associated with CTS.