Diagnosis of carpal tunnel syndrome in perspective of clinical features, neurophysiological studies and high resolution ultrasound

Carpal tunnel syndrome (CTS) is compression of median nerve during its course through the carpal tunnel in the hand. CTS is the most common mononeuropathy diagnosed in neurological clinics.  CTS can cause pain, psychological distress, decreased performance at work, absentia from work and financial loss. The diagnosis is mainly based on high degree of clinical suspicion with positive clinical symptoms and signs and must be confirmed with either neurophysiological testing or high resolution ultrasonography. Neurophysiological studies had been the gold standard in diagnosis and grading CTS and for excluding it from other neuromuscular disorder. High resolution ultrasound is being increasingly utilized to diagnose CTS as it can show the pathology of CTS such as swelling and inflammation of median nerve and bowing of flexor retinaculum indicating compressive median neuropathy at the carpal tunnel. It is noninvasive, painless and cheaper but the measurements are operator dependent. Neurophysiological studies have well defined criteria for grading. The use of combined ultrasound and neurophysiological study show greater sensitivity and specificity than the individual procedures and can provide greater clarity to avoid false positive and false negative results.  High resolution ultrasonography can help in evaluation of persistence of symptoms even after surgical release and to detect anatomical variations. Early diagnosis and grading is critical in following the appropriate treatment strategy. Clinical features, neurophysiological studies and ultrasound are valuable tools in the identification and assessment of CTS whenever each is used individually or as complementary to each other.