Diagnostic value of the clinical examination for diagnosing carpal tunnel syndrome assisted with nerve conduction studies

Abstract

Nerve conduction studies (NCS) are the most reliable methods in diagnosis of carpal tunnel syndrome (CTS). Although there are many clinical finding associated with CTS, there are a limited number of studies in the literature indicating the objective value of these finding for diagnosing. To evaluate the reliability of clinical examination in diagnosing CTS, with the help of NCS and detection of comorbid diseases likely to be risk factors in the CTS. We accepted 463 patients, who visited our outpatient clinic and presented with paresthesia or pain at the median nerve distribution. Demographic data, clinical findings and comorbidities were recorded. According to the NCS results, patients were divided two groups (positive or negative) and analyzed. Only 51.1% of the patients were negative and 48.9% were positive according to NCS. The highest sensitivity was at Durkan's test (95.6%) and lowest was at thenar atrophy (22.1%). The highest specificity and positive predictive value were at thenar atrophy (100%) and the lowest were at Tinel's test (40.9% and 59.1). The highest negative predictive value was at Durkan's test (94%) and the thenar atrophy was the lowest (57.4%). There was a significant difference between the clinical findings in NCS groups ( P < 0.001). A total of 46.9% of the patients were had comorbidities. Hypertension, diabetes and obesity were the most common comorbidities. There was a significant difference between the groups for diabetes, obesity, rheumatoid arthritis, hypothyroidism and gout ( P < 0.05). Thenar atrophy and sensory loss were highly specific in CTS but had limited value in early detection, due to their low sensitivities and observations in more advanced stage patients. For their low specificity, provocative tests seem to be insufficient to establish a definite CTS diagnosis. Maybe only Durkan's test could be considered primarily with more balanced values. Diabetes, obesity, rheumatoid arthritis, hypothyroidism and gout were significantly increasing the CTS risk.