Ulnar neuropathy with normal electrodiagnosis and abnormal nerve ultrasound

Measurement of cross-sectional area of cervical roots and brachial plexus trunks

INTRODUCTION

The aim of this study was to determine normal reference values for cross-sectional area (CSA) and the correlation between demographic factors and CSA in the cervical roots and brachial plexus trunks using ultrasonography.

METHODS

Ninety-five age-matched healthy individuals were studied. Ultrasonographic tests were performed via nerve tracing from the cervical root to the brachial plexus trunk. The CSA of each nerve was measured in the C5-8 ventral roots and brachial plexus (trunk level).

RESULTS

Normal values of each cervical root were: C5, 5.66 ± 1.02 mm(2); C6, 8.98 ± 1.65 mm(2); C7, 10.43 ± 1.86 mm(2); and C8, 10.76 ± 2.02 mm(2). Values for the brachial plexus were: upper trunk, 16.70 ± 2.88 mm(2); middle trunk, 14.01 ± 2.70 mm(2); and lower trunk, 13.75 ± 2.57 mm(2). The side-to-side discrepancy was 11.91 ± 11.11%. Body mass index (BMI) and height correlated frequently with nerve CSA.

CONCLUSIONS

These reference values may be helpful in investigating pathologies involving the cervical area.

Diagnostic value of ultrasonography and magnetic resonance imaging in ulnar neuropathy at the elbow

Aim. To evaluate the diagnostic value of ultrasonography and magnetic resonance imaging (MRI) in patients with ulnar neuropathy at the elbow (UNE). Methods. We prospectively performed electrodiagnostic, ultrasonographic, and MRI studies in UNE patients and healthy controls. Three cross-sectional area (CSA) measurements of the ulnar nerve at multiple levels along the arm and maximum CSA(-max) were recorded. Results. The ulnar nerve CSA measurements were different between the UNE severity grades (P < 0.05). CSA-max had the greatest sensitivity (93%) and specificity (68%). Moreover, CSA-max ≥10 mm² defined the severe UNE cases (sensitivity/specificity: 82%/72%). In MRI, ulnar nerve hyperintensity had the greatest sensitivity (90%) and specificity (80%). Conclusion. Ultrasonography using CSA-max is sensitive and specific in UNE diagnosis and discriminating the severe UNE cases. Furthermore, MRI particularly targeting at increased signal of the ulnar nerve can be a useful diagnostic test of UNE.