The cross-sectional morphology of median nerve in carpal tunnel of healthy, adult population: A systematic review and meta-analysis

Abstract

The full text of manuscripts were collected after short-listing the abstracts collected from search strategy. A quality assurance tool was used to capture the risk of bias of each study after reviewing the included manuscripts. The pooled estimate of cross-section area was stratified according to anatomical landmarks, sex, and ancestry. A total of 97 observational studies dealt with 6679 wrists of healthy subjects were included. The pooled estimate of the cross-section area of median nerve at carpal tunnel inlet was 8.54mm2 [95% CI: 8.34-8.74mm2]. The same pooled estimate at carpal tunnel outlet was 8.03mm2 [95% CI: 7.46-8.60mm2]. Both these pooled estimates have significant correlation with mean age of population. Age and sex were two primary predictors of the cross-section of median nerve. The flattening ratio, circularity, and wrist-forearm ratio of median nerve were also computed. These normative data could serve as a reference for assessing median nerve pathologies, including carpal tunnel syndrome. The ethnic variation of pooled estimate and heterogeneity will guide clinician set up the reference value for diagnostic criteria.