128. Single fiber electromyography with a concentric needle electrode and surface stimulus in the orbicularis oculi muscle

Abstract

arthroscopy 3 months prior, using three standard ankle port sites, subsequently developed precisely delineated numbness and pain of the right ankle and foot. Physical examination showed heterogeneous sensory disturbance and hypersensitivity throughout the entire dorsum of the foot, as well as extensor digitorum brevis atrophy. Electrodiagnosis demonstrated neuropathy of the right saphenous, superficial fibular sensory, and distal deep fibular nerves. High frequency ultrasound was utilized for further localization and assessment. Ultrasonography demonstrated loss of the fasicular architecture and fusiform swelling of the affected nerves precisely at the port sites, but continuity was demonstrated with each nerve. Conclusion: This case demonstrates the utility of high frequency ultrasound in the assessment of traumatic neuropathies. Using this modality provided evidence of continuity (i.e., no neurotmesis) in the nerves that had absent sensory nerve action potentials. It also provided more precise localization of the injury than electrodiagnostic techniques alone. Additionally, this is the first reported case, to the authors’ knowledge, demonstrating ultrasonographic evidence of nerve disruption following a standard ankle arthroscopic procedure.