Diagnosis and pathophysiology of carpal tunnel syndrome

Purpose of review Carpal tunnel syndrome is the most commonly reported compression neuropathy. Awareness of the syndrome has increased the frequency of diagnosis. Yet controversy remains regarding the exact mechanism of nerve compression and the existence of a true gold standard for the diagnosis of carpal tunnel syndrome. We examine recent literature regarding pathophysiology and diagnostic criteria. Recent findings Our understanding of changes in the carpal tunnel and median nerve as seen with magnetic resonance imaging and ultrasound continues to improve. These show promise, both as screening tests and to enable understanding of the causes of carpal tunnel syndrome. A clinical diagnostic standard has been proposed, and may allow better comparison among studies. Obesity and age are independent risk factors. Findings and symptoms differ depending on the population examined, with more severe findings in the elderly for given symptoms. Summary Carpal tunnel syndrome is a clinical diagnosis. Electrodiagnostic studies are frequently useful in further evaluation of cases. Alternate imaging methodologies may become useful as screening tools in the future. Causes are related to mechanical strain and increased carpal canal pressures. Noninvasive imaging is assisting in defining the anatomy and dynamic nature of the carpal tunnel with movement.