@Article{Tabatabaeifar2017, author = "Tabatabaeifar, Sorosh and Svendsen, Susanne Wulff and Johnsen, Birger and Hansson, Gert-Åke and Fuglsang-Frederiksen, Anders and Frost, Poul", title = "Reversible median nerve impairment after three weeks of repetitive work", journal = "Scandinavian Journal of Work, Environment & Health", year = "2017", month = "Mar", day = "43", number = "2", pages = "163--170", keywords = "carpal tunnel syndrome; CTS; median nerve; median nerve impairment; nerve conduction study; nerve impairment; occupational exposure; repetitive work", abstract = "'
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OBJECTIVES ': 'The aim of this study was to evaluate the development of impaired median nerve function in relation to hand-intensive seasonal work. We hypothesized that at end-season, median nerve conduction would be impaired and then recover within weeks.
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METHODS ': 'Using nerve conduction studies (NCS), we examined median nerve conduction before, during, and after engaging in 22 days of mink skinning. For a subgroup, we used goniometry and surface electromyography to characterize occupational mechanical exposures. Questionnaire information on symptoms, disability, and lifestyle factors was obtained.
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RESULTS ': 'The study comprised 11 male mink skinners with normal median nerve conduction at pre-season (mean age 35.7 years, mean number of seasons with skinning 8.9 years). Mink skinning was characterized by a median angle of wrist flexion/extension of 16º extension, a median velocity of wrist flexion/extension of 22 °/s, and force exertions of 11% of maximal voluntary electrical activity. At end-season, mean distal motor latency (DML) had increased 0.41 ms (P<0.001), mean sensory nerve conduction velocity (SNCV) digit 2 had decreased 6.3 m/s (P=0.004), and mean SNCV digit 3 had decreased 6.2 m/s (P=0.01); 9 mink skinners had decreases in nerve conduction, 5 fulfilled electrodiagnostic criteria and 4 fulfilled electrodiagnostic and clinical criteria (a positive Katz hand diagram) for carpal tunnel syndrome (CTS). Three to six weeks post-season, the changes had reverted to normal. Symptom and disability scores showed corresponding changes.
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CONCLUSIONS ': 'In this natural experiment, impaired median nerve conduction developed during 22 days of repetitive industrial work with moderate wrist postures and limited force exertion. Recovery occurred within 3–6 weeks post-season.
", issn = "0355-3140", doi = "10.5271/sjweh.3619", url = "https://www.sjweh.fi/show_abstract.php?abstract_id=3619", url = "https://doi.org/10.5271/sjweh.3619" }