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Reversible median nerve impairment after three weeks of repetitive work

Tabatabaeifar, Sorosh; Svendsen, Susanne Wulff; Johnsen, Birger; Hansson, Gert Åke LU ; Fuglsang-Frederiksen, Anders and Frost, Poul (2017) In Scandinavian Journal of Work, Environment and Health 43(2). p.163-170
Abstract

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. 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. 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... (More)

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. 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. 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. 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.

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author
organization
publishing date
type
Contribution to journal
publication status
published
subject
keywords
Carpal tunnel syndrome, CTS, Median nerve, Median nerve impairment, Nerve conduction study, Nerve impairment, Occupational exposure, Repetitive work
in
Scandinavian Journal of Work, Environment and Health
volume
43
issue
2
pages
8 pages
publisher
Finnish Institute of Occupational Health
external identifiers
  • scopus:85014675076
  • wos:000395849200009
ISSN
0355-3140
DOI
10.5271/sjweh.3619
language
English
LU publication?
yes
id
3e7ba392-6ea8-4978-ae72-1d34a2e1513b
date added to LUP
2017-04-07 10:48:50
date last changed
2017-09-18 13:31:45
@article{3e7ba392-6ea8-4978-ae72-1d34a2e1513b,
  abstract     = {<p>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. 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. 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&lt;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. 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.</p>},
  author       = {Tabatabaeifar, Sorosh and Svendsen, Susanne Wulff and Johnsen, Birger and Hansson, Gert Åke and Fuglsang-Frederiksen, Anders and Frost, Poul},
  issn         = {0355-3140},
  keyword      = {Carpal tunnel syndrome,CTS,Median nerve,Median nerve impairment,Nerve conduction study,Nerve impairment,Occupational exposure,Repetitive work},
  language     = {eng},
  number       = {2},
  pages        = {163--170},
  publisher    = {Finnish Institute of Occupational Health},
  series       = {Scandinavian Journal of Work, Environment and Health},
  title        = {Reversible median nerve impairment after three weeks of repetitive work},
  url          = {http://dx.doi.org/10.5271/sjweh.3619},
  volume       = {43},
  year         = {2017},
}