Ramazzini; Blog on work and health by Annet Lenderink

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Not so easy to diagnose carpal tunnel syndrome

To evaluate the utility of physical examination manoeuvres in the prediction of carpal tunnel syndrome (CTS) a cohort of 1108 newly employed workers in several industries was studied. Each worker completed a symptom questionnaire, a structured physical examination and nerve conduction study. To diagnose CTS both median nerve conduction abnormality and symptoms classified as “classic” or “probable” on a hand diagram were required. The prevalence of CTS in our cohort was 1.2% for the right hand and 1.0% for the left hand. The post-test probability of positive testing was <50% for all strategies tested. In this study it turned out that physical examination, alone or in combination with symptoms, was not predictive of CTS in a working population. Researchers suggest using specific symptoms as a first-level screening tool, and nerve conduction study as a confirmatory test

Diagnostic strategies using physical examination are minimally useful in defining carpal tunnel syndrome in population-based research
 Descatha, A, Dale, A-M, Franzblau, A, Coomes, J, Evanoff, B
Occup Environ Med 2010;67:133-135 doi:10.1136/oem.2009.047431

Objective: We evaluated the utility of physical examination manoeuvres in the prediction of carpal tunnel syndrome (CTS) in a population-based research study.

Methods: We studied a cohort of 1108 newly employed workers in several industries. Each worker completed a symptom questionnaire, a structured physical examination and nerve conduction study. For each hand, our CTS case definition required both median nerve conduction abnormality and symptoms classified as “classic” or “probable” on a hand diagram. We calculated the positive predictive values and likelihood ratios for physical examination manoeuvres in subjects with and without symptoms.

Results: The prevalence of CTS in our cohort was 1.2% for the right hand and 1.0% for the left hand. The likelihood ratios of a positive test for physical provocative tests ranged from 2.0 to 3.3, and those of a negative test from 0.3 to 0.9. The post-test probability of positive testing was <50% for all strategies tested.

Conclusion: Our study found that physical examination, alone or in combination with symptoms, was not predictive of CTS in a working population. We suggest using specific symptoms as a first-level screening tool, and nerve conduction study as a confirmatory test, as a case definition strategy in research settings.

Filed under: Musculoskeletal problems, Occupational injury, Occupational medicine, ,

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