Nerve high-resolution ultrasound in a 2-year follow-up of radial nerve palsy related to humeral shaft fractures.

Background: High-resolution nerve ultrasonography (HRUS) could have an emerging importance in diagnosis and follow-up of axonopathic radial palsy associated with humeral shaft fractures due to closed trauma. The aim of our study was to establish the role of HURS in this context through a longitudinal multimodal analysis.

Methods: Clinical, electrodiagnostic (EDX) and HRUS evaluations were prospectively performed at month 1, 3, 6, 12 and 24 from injury, in a continuous series of 19 patients collected in a 5-year study. Clinical severity was scored on MRC of involved muscles, EDX on presence/absence of functional continuity; anatomical continuity and nerve cross sectional area (NCSA) of radial (RN) and posterior interosseus (PIN) nerves were evaluated through HRUS.

Results: All patients showed clinical improvement during follow-up; EDX functional continuity was reached by all patients within 12 months; HRUS revealed RN anatomical continuity in all patients and PIN involvement in 74%. RN NCSA progressively reduced during FU, but it was still significantly higher than contralateral at month 24; PIN NCSA became normal within 24 months.

Conclusions: When anatomical RN continuity is confirmed by HRUS, good functional outcome is reached even in patients with EDX loss of functional continuity. Together with clinical and EDX evaluations, HRUS may provide useful data in the follow-up of radial palsy due to humeral shaft fractures.