1. Results Methods: Conclusions References: Background:
A PROSPECTIVE STUDY EXAMINING THE SENSITIVITY OF ULTRASOUND DETERMINED MEDIAN NERVE CROSS-SECTIONAL AREA WITH NERVE CONDUCTION INVESTIGATION IN THE DIAGNOSIS OF CARPAL TUNNEL SYNDROME (CTS).
Beena Hameed1, Tamim Khanbhai2, Peter Resteghini3, Stephen Bourke4, 1.Rheumatology, 2.Sports Medicine, 4.Radiology, Homerton University Hospital, london, UK.
Background:
Results
Diagnosis of CTS with nerve conduction studies (NCS) rests upon demonstrating impaired median nerve conduction across the carpal tunnel in the context of normal conduction elsewhere. Imaging techniques provide alternative means of diagnosis for CTS. High-resolution US allows non-invasive imaging of the carpal tunnel and its contents with several advantages over MRI, including being relatively fast and inexpensive and allowing additional dynamic and blood flow imaging with relatively little additional time.
Ultrasound diagnosed more wrists with median nerve pathology 50/56 (88%) than EMG 38/56 (53%). Overall no strong correlations were found between clinical measures and either EMG or ultrasound (CSA). Ultrasound (CSA) co-related significantly with EMG (p=0.007). The wrist to fore-arm (WFR) measures correlated weakly with the EMG (p=0.205).
Objectives:This study examines sensitivity of ultrasound in confirming CTS
in comparison to NCS in patients with clinically defined CTS.
Methods:
28 patients (56 wrists), (mean age 53 years, range years) with CTS were enrolled. Clinical parameters were recorded at one time point by: phalens’test, sensory deficit and motor deficit in median nerve distribution by two clinicians by consensus who were blinded to either NCS or US findings. Ultrasound assessment (Gray scale and Power Doppler using GE Logic E9 and a ML6-15Hz transducer) of the median nerve was performed (cross-sectional area [CSA] measurement at the proximal carpal tunnel, at the level of the pronator quadratus muscle and 12 cm proximally in the mid forearm) by two observers (radiologist or trained radiographer) by consensus, however were blinded to clinical or NCS examination of these patients. In addition the flexor retinaculum was assessed for degree of bowing and the median nerve was assessed for intra-neural hyper-vascularisation. The relation between each measure of median nerve assessment was determined by Spearman Correlation analysis.
Conclusions
In CTS ultrasound examination performed over and above NCS in confirming diagnosis. Milder cases where, NCS reports normal examination may be diagnosed by ultrasound examination. Larger studies are needed to determine the relative predictive power of ultrasound in diagnosing mild carpal tunnel syndrome.
References:
Padua L etal. Carpal tunnel syndrome: ultrasound, neurophysiology, clinical and patient oriented assessment. Clin Neurophysiol Sep;119(9):2064-9