Different case definitions to describe the prevalence of occupational carpal tunnel syndrome in meat industry workers

Objectives: The aim of this study was to assess the prevalence of carpal tunnel syndrome (CTS) in a group of meat industry workers, using typical symptoms, median nerve conduction studies (NCSs) and their combinations. In the case definition including the NCSs, we tested the electrodiagnostic reference values derived from the general healthy population and from the asymptomatic study population. Methods: One-hundred fourteen workers were examined by clinical interviews and median NCSs. Results: The prevalence of CTS varied from 11% to 53%, with a progressive reduction passing from symptoms to NCSs to the their combinations. The prevalence was identical and the highest at the same time (53%) considering the case definitions based only on the symptoms and only on the NCSs with Kimura's reference values. Using the asymptomatic workers' electrodiagnostic reference values, alone or in combination with symptoms, the prevalence of CTS was the lowest (respectively, 15% and 11%). Conclusions: In the epidemiological studies, median NCSs should be considered desirable, if not essential, for confirming a clinical diagnosis, most of all in the longitudinal studies. In the future of CTS diagnosis, attention should be paid to the electrodiagnostic reference values that are discriminating to confirm the presence or not of the disease.