Usefulness of neuromuscular ultrasound in the diagnosis of idiopathic carpal tunnel syndrome

Abstract

ObjectiveThe aim of the study was to assess the usefulness of neuromuscular ultrasound in the diagnosis of idiopathic carpal tunnel syndrome (CTS) and to determine the relationships of ultrasonographic measurements with the clinical severity and the electrophysiological grading scale.Patients and methodsOne hundred CTS diseased hands and 100 nondiseased hands were assessed clinically and by nerve conduction studies. We measured ultrasonographic cross-sectional area (CSA) of the median nerve at various levels of the carpal canal (inlet and outlet), flattening ratio (FR), palmar bowing of the flexor retinaculum, wrist/ forearm ratio, as well as median nerve mobility and power doppler signals. Data from patients and controls were compared to determine the diagnostic relations and the grade of severity.ResultsMeasures of CSA of the median nerve at the inlet and at the outlet, palmer bowing and inlet/forearm ratio in the CTS group were significantly higher than the control group (P<0.05); 50% of diseased hands showed restriction of mobility of the median nerve, while 31% had doppler signals. Positive correlations of ultrasonographic measurements with patient-oriented measures, clinical severity scale and electrophysiological grade were observed.ConclusionUltrasonographic measurements of CSA at the inlet and flexor retinaculum have a relatively higher diagnostic accuracy than FR for CTS. The correlation between clinical scores, historical-objective-distribution scale, electrophysiological grade and ultrasonographic measurements reflects the usefulness of neuromuscular ultrasound in the diagnosis of idiopathic CTS.