Carpal tunnel syndrome: Analyzing efficacy and utility of clinical tests and various diagnostic modalities

BACKGROUND: Carpal tunnel syndrome (CTS) is the most common entrapment neuropathy, but not adequately studied in India. OBJECTIVES: To study clinical tests, nerve conduction studies (NCS), ultrasonography (USG), and magnetic resonance imaging (MRI) in diagnosing CTS. MATERIALS AND METHODS: We diagnosed CTS in 54 patients (93 hands) out of 60 screened patients with symptoms compatible with CTS, including 19 control patients (23 hands). We conducted provocative tests and calculated Boston Carpal tunnel Questionnaire (BCTQ) symptom (S) and function (F) scores. NCS positive patients were classified into mild, mild-to-moderate, moderate, severe, and all-CTS groups. Median nerve anteroposterior, transverse, circumference (CIR), and cross-sectional area (CSA) at inlet (I), middle (M), and outlet (O) each was measured by USG in all patients. MRI was done in 26 patients (39 hands). RESULTS: Phalen, hand elevation and pressure provocation tests had higher sensitivity, Tinel's test had higher specificity and tethered median nerve and tourniquet tests had low sensitivity and moderate specificity. USG had low sensitivity but high specificity, and MRI had moderate sensitivity. USG in patients compared to controls was significantly abnormal in CSA-I, CIR-I, and CSA-O. Significant correlation was found between BCTQ-S and NCS and BCTQ-S and CIR-O. CIR-M, CIR-O, CSA-M, and CSA-I had correlation with NCS. MRI was significant in moderate and in moderate + severe groups combined and associated pathologies were detected in 59% patients. CONCLUSION: NCS remain gold standard but USG and MRI help increase sensitivity and detect mass lesions amenable to surgery.