Carpal Tunnel Syndrome Diagnosis: A Narrative Review of Complementary Roles of Neuromuscular Ultrasound and Electrodiagnostic Studies

Carpal tunnel syndrome (CTS), the most prevalent entrapment neuropathy of the upper extremities, presents diagnostic challenges due to nonspecific clinical symptoms and discrepancies between subjective experiences and objective findings. Traditional reliance on electrodiagnostic studies (EDX), including nerve conduction studies (NCS) and electromyography, as the traditional reference method for assessing median nerve function is limited by invasiveness, operator dependency, and reduced sensitivity in mild cases. Neuromuscular ultrasound (NMUS) has emerged as a non-invasive complementary imaging method, enabling visualization of morphological changes such as increased median nerve cross-sectional area (CSA) and restricted gliding. This narrative review synthesizes evidence on the diagnostic utility of NMUS and EDX. We found that while EDX remains the reference standard for functional grading (eg, distal motor latency), it is limited by its invasiveness. Conversely, NMUS excels in identifying anatomical pathologies (eg, CSA ≥10 mm²) but is operator dependent. Rather than using a single tool, we demonstrate that combining EDX's physiological precision with NMUS's anatomical visualization offers the highest diagnostic accuracy. Recent trends favor artificial intelligence (AI) integration and standardized multimodal protocols to bridge the current implementation gaps.