Carpal tunnel syndrome is the most expensive upper extremity work-related musculoskeletal disorder, impacting 10 million people annually and costing employers up to $113,695 per incident. Although many etiologic mechanisms have been identified, one set of factors cannot accurately predict carpal tunnel syndrome development. As a result, carpal tunnel syndrome interventions are often provided reactively after initial symptom reports or inefficiently to employees perceived to be at risk. As the disorder progresses, it becomes increasingly expensive to treat and functional limitations become more challenging to remediate. There is currently no established method to detect this disorder prior to the onset of symptoms and nerve damage. Preliminary research suggests that sonography-a relatively inexpensive, widely available, increasingly portable technology-can provide a non-invasive and pain-free method of early detection that could reduce incidence, improve targeted interventions and ultimately reduce costs. Sonographic imaging has been used in an animal model to observe early progressive increases in median nerve size due to task exposure. By understanding this progression in humans, it would be possible to develop an early detection technique to stop, slow, or reverse this disorder before it becomes costly and debilitating. Thus, the long-term goal of this work is to develop a model of morphologic changes predictive of the onset and development of work-related carpal tunnel syndrome. As a first step, this study will establish predictive validity of a novel method for early detection using sonographic imaging and identify task components of intensive functional hand activity associated with morphologic changes. This longitudinal study will follow dental hygiene students-a high-risk population with minimal retrospective and controlled prospective task exposure-for two years to investigate these aims. This research is directed at the National Occupational Research Agenda's (NORA) Healthcare and Social Assistance sector with a focus on the National Institute of Occupational Safety and Health's (NIOSH) Exposure Assessment and Musculoskeletal Disorders cross-sectors. Intermediate outcomes of this research will establish sonographic imaging as an early detection tool for workplace-screening and inform methods for combining measures of nerve morphology, neurophysiology, and subjective symptoms for predicting the development of work-related carpal tunnel syndrome. This work will also inform the development of targeted preventive interventions for task components of intensive hand activities that are related to changes in tissue morphology. Finally, this work will provide access to a cohort of individuals who can be followed as they transition into the workforce to document the natural development of work-related musculoskeletal disorders. Identifying morphologic changes in early-stages of pathology and the specific task components linked to these changes are the first steps toward early detection and prevention of work-related carpal tunnel syndrome.
Sonography is a relatively inexpensive, increasingly portable technology that could revolutionize prevention for work-related median nerve pathology through early detection and routine follow-up at the worksite. Capturing median nerve pathology in early stages will lead to shortened time to diagnosis, improved targeting of interventions, and significant cost savings.
