Diagnostic tests used in diagnosis of carpal tunnel syndrome

In 1854 Paget described for the first time that carpal tunnel syndrome (CTS) results from compression of the median nerve within the carpal tunnel. CTS predominantly involves tingling and numbness in the typical median nerve distribution. Pain, described as deep, aching, or throbbing, occurs diffusely in the hand and radiates up the forearm. Atrophy of the muscles of the thenar is usually seen later in the course of the nerve compression. CTS is most frequent among persons between the ages of 30 to 60 and is two to three times more common in women than in men (peak prevalence in women older than 55 years). Carpal tunnel syndrome may affect 1% to 10% of the population. Incorrect diagnosis of CTS has been identified as one of the most common causes of CTS treatment failure. CTS should be diagnosed clinically. Electro-diagnostic studies are a standard method of establishing the diagnosis. Electrodiagnostic studies are performed to confirm the clinical diagnosis, to assess the severity of median nerve compression and to rule out more proximal compression sites. Abnormalities in nerve conduction study results can be the only objective evidence of carpal tunnel syndrome. Lack of objective data, such as ENG can lead to incorrect diagnosis and inappropriate treatment. Clinical diagnosis should be reinforced by valuable diagnostic tests: the Semmes–Weinstein monofilaments test – performed in neutral and Phalen’s positions, vibration threshold measured by means of tuning forks or a vibrometer, by observation of thenar atrophy and using provocative tests. The use of common, sensitive and specific diagnostic tests should improve decision making about patients referral for specific therapies, facilitate the performance of epidemiologic studies, increase the accuracy of diagnosis. The combination of a results obtained using various methods might be more powerful than a single test in establishing the diagnosis of CTS. The combination of hand diagram, questionnaires, abnormal sensibility, thenar weakness or thenar atrophy and positive provocative tests constitutes a sensitive and specific diagnostic tool to establish the diagnosis of CTS. Standardized clinical criteria for CTS would be an important step in reducing inconsistencies and misdiagnoses.