Diagnostic value of high-resolution sonography in common fibular neuropathy at the fibular head

In 30% of patients with common fibular (CF) neuropathy at the fibular head, reliable localization of the site of the lesion by means of electrodiagnostic testing is challenging.

We prospectively assessed proximal CF nerve cross-sectional area (CSA) measurements and at the fibular head in 87 patients with CF neuropathy and 16 with a different condition. Reference values were obtained in 64 healthy volunteers.

Patients with CF neuropathy had a significantly larger CF nerve CSA than controls and patient controls (P < 0.0001). Sonography localized the lesion at the fibular head in 55% and just above it in 71% of patients. Assessment of the most thickened part of the CF nerve resulted in a cut-off value of >8 mm² with a sensitivity of 90% (CI 81-95%) and a specificity of 69% (CI 58-78%).

High-resolution sonography in addition to electrodiagnostic testing improves diagnostic reliability in CF neuropathy.