Relationship of BMI and wrist joint index with carpal tunnel syndrome in manual laborers

Objective To evaluate the severity of median nerve damage in patients with carpal tunnel syndrome (CTS) , and to analyze its relationship with body mass index (BMI) and wrist joint index. Methods From May 2016 to January 2017, 23 patients with mild CTS (mild group) and 35 patients with moderate to severe CTS (moderate to severe group) were enrolled in this study. And 22 healthy volunteers matched for sex and age were selected as control group. The neuroelectrophysiological monitor was used to measure the median nerve movement and sensory nerve conduction in the subjects. The BMI and wrist joint index were calculated. The relationship of neuroelectrophysiological parameters with BMI and wrist joint index was analyzed in the CTS patients. Results Compared with the control group, the mild group and the moderate to severe group had significantly higher wrist joint index, significantly longer distal motor latency (DML) of the median nerve, and significantly lower sensory nerve conduction velocity (SNCV) and sensory nerve action potential (SNAP) amplitude of the finger 1-wrist and finger 3-wrist (P 0.73 had a significantly higher risk of CTS than those with a wrist joint index of <0.73 (odd ratio=30.67, 95% confidence interval: 3.79-248.36) . Conclusion A wrist joint index of >0.73 is an independent risk factor for CTS in manual laborers. CTS should be prevented in the manual laborers with high wrist joint index and BMI. Key words: Carpal tunnel syndrome; Body mass index; Electrophysiological examination; Wrist index