The objective of this study was to compare the probability of carpal tunnel syndrome diagnosed on electrodiagnostic testing with the probability of it being present after the diagnosis was established on the basis of a clinical evaluation alone. The clinical evaluation utilized the CTS-6, a validated diagnostic aid that estimates the probability of carpal tunnel syndrome based the presence or absence of six clinical findings. These include symptoms and history (that is numbness predominantly or exclusively in the median nerve territory), nocturnal numbness, physical examination of thenar atrophy and/or weakness, a positive Phalen’s test, loss of two point discrimination, and a positive Tinel’s sign.
Not surprisingly, the results show that in the majority of patients who are considered to have carpal tunnel syndrome on the basis of their history and physical examination alone, electrodiagnostic tests do not change the probability of diagnosing this condition to an extent that is clinically relevant. This paper has relevance to all physicians who treat carpal tunnel syndrome, including primary care providers. Although hand doctors will have variable comfort levels with respect to preoperative testing prior to surgery, electrodiagnostic studies do not appear to be necessary to confirm the diagnosis of carpal tunnel syndrome in straightforward cases.