Time’s Toll on the Tunnel: How Aging Affects the Median Nerve and Carpal Tunnel

PURPOSE: Prior studies suggest carpal tunnel syndrome (CTS) is primarily associated with structural, genetic, and biological factors, while occupational and environmental contributors, such as repetitive hand use, demonstrate weaker inconsistent correlations (1-3). CTS commonly presents between the fourth and sixth decades of life, raising the question: Why do some individuals develop CTS as they age? This study examines age-related variations in carpal tunnel and median nerve volumes and cross-sectional areas in individuals without CTS using MRI to explore potential anatomical predispositions for CTS development. METHODS: This single-institution study utilized MRI scans of the wrist from individuals aged 20-70 years. Participants were grouped into decade-based cohorts: 20-30, 31-40, 41-50, 51-60, and 61-70 years. Exclusion criteria included prior wrist trauma or wrist surgery, diabetes, rheumatoid arthritis, or a clinical diagnosis of CTS to ensure observed changes were age-related rather than pathological. MRI images were analyzed using Visage Imaging and Materialize Mimics software for volumetric segmentation of the carpal tunnel and median nerve. Standardized anatomical landmarks were used for measurements. Statistical analysis included descriptive statistics, independent t-tests to compare mean differences between age groups, and Fisher’s exact test for categorical variables, with significance set at p<0.05. RESULTS: To date, 46 individuals aged 20-30 years, 42 aged 31-40 years, 35 aged 41-50 years, 36 aged 51-60 years, and 30 aged 61-70 years have been analyzed. Carpal tunnel volume exhibited a decreasing trend with age, though this was not statistically significant. The highest mean volume was in the 31-40 age group (4716.06 mm³), while the lowest was in the 61-70 age group (4160.89 mm³), suggesting a steady reduction across cohorts. Similarly, median nerve volume progressively declined from 254.23 mm³ in the 20-30 group to 233.05 mm³ in the 61-70 group, indicating potential age-related nerve atrophy. The carpal tunnel inlet-to-outlet cross-sectional area ratio remained consistent across cohorts, but the median nerve ratio significantly increased with age, suggesting potential increased nerve compression. CONCLUSIONS: Aging is associated with a measurable decline in both carpal tunnel and median nerve volumes, suggesting a potential role in CTS risk. Although statistical significance has not been reached, ongoing data collection may clarify these trends. The observed volumetric decline suggests that anatomical changes in the wrist may increase susceptibility to neuropathic symptoms. These findings highlight the importance of age-related anatomical factors beyond traditional CTS risk factors, such as occupation, trauma, diabetes, and hormonal influences. Recognizing these age-related changes may aid in early identification of CTS risk and inform preventive strategies.