Correlation between clinical suspicion of carpal tunnel syndrome and neurophysiology studies

Abstract

Carpal tunnel syndrome (CTS) it's one of the most frequent diagnosis referred to the electrodiagnostic laboratory. Nerve conduction velocities (NCV) and electromyography (EMG) usually confirm the diagnosis. To assess the clinical accuracy between referred hospital services and electrodiagnostic studies. We assessed 107 requests of studies of patients who were referred with the clinical suspicion of CTS, uni or bilateral to the Instituto Nacional de Nutrición at Mexico City, from 2016 to 2019. We obtained informed consent and classified the reports into five groups according to the specialty from which the request came. We performed a standard NCV/EMG and the rate of clinical misdiagnosis was determined individually for five groups specialties; we used SPSS® version 25 software to analyze data and evaluate with the Chi square if there were any difference clinical diagnostic accuracy between the specialties. Five reports were excluded for insufficient information. NCV were normal in 38.8% of patients with clinically suspect CTS. By electrodiagnostic methods the diagnosis was confirmed in 88.8% of cases referred from plastic surgery, 83.3% from endocrinology and 72.2% from internal medicine. For rheumatology and neurology this ratios were 63.6% and 51.8%, respectively. There was no statistically significant difference for clinical presumption of CTS between specialties. Electrodiagnosis studies might confirm the diagnosis, but we know that these studies may show up to 10-20% of false positive, some misdiagnosis could be explained by this fact. We suggest the implementation of standardized clinical questionnaire for diagnosis of CTS to improved clinical accuracy.