Correlation of body composition and anthropometric indices with electrodiagnostic and ultrasonographic findings in patients with carpal tunnel syndrome.

Objective: Carpal tunnel syndrome (CTS) is the most common entrapment neuropathy of the upper limb. Various risk factors have been described for this disorder. This study aimed to investigate the relationship between CTS with body composition indexes and hand anthropometric characteristics.

Design: This is a case-control study.

Setting: The study conducted in physical medicine and rehabilitation clinic at Firoozgar Hospital, Iran University of Medical Sciences between 2019 and 2020.

Participants: Fifty patients with clinical symptoms of CTS and 50 controls were enrolled.

Intervention: The median nerve distal sensory latency (DSL) and amplitude, and distal motor latency (DML) and amplitude, were measured using a Natus Synergy Ultrapro S100 instrument.

Main outcomes measure: Age, hand anthropometric index, body weight, body mass index (BMI), body composition indexes and sonographically measured cross-sectional area (CSA) of median nerve were evaluated in both groups, and the relation between these variables as the incidence of CTS and its severity were investigated.

Results: We observed a significant correlation between CTS incidence and larger dorsovolar and mediolateral diameters of the wrist (all with P < 0.05). The right median nerve CSA was 14.94 ± 6.00 mm2 in the case group, and 10.88 ± 2.19 mm2 in the control group, and the left CSA was 14.17 ± 5.00 mm2 in the case group and 10.72 ± 2.17 mm2 in the control group, all with P < 0.001. The mean weight, BMI, fat mass, and total extracellular water (ECW) ratio were significantly higher in the case group. There was no significant relationship between CTS severity and weight and body composition indexes (all with P > 0.05) except for median nerve CSA.

Conclusions: Our study showed that among the body composition indexes, the body fat mass, as an indicator of the body fat distribution, and total ECW ratio are associated with the incidence of CTS while not its severity. Higher body weight, BMI, fat mass, total ECW ratio, median nerve CSA and wrist diameters increase the risk of CTS. Higher median nerve CSA is also associated with the higher severity of CTS.