Electrophysiological Profile and Comparative Analysis in Brachial Plexus Injuries

BACKGROUND AND OBJECTIVES: Brachial plexopathies (BPs) are disabling peripheral nerve disorders resulting in significant motor and sensory deficits. Traumatic BP is the most common etiology, typically following high-energy injuries, while non-traumatic causes include inflammatory and other etiologies. Although imaging provides anatomical detail, electrodiagnostic studies-nerve conduction study (NCS) and needle electromyography (EMG)-remain central to functional assessment. METHODS: We conducted a retrospective observational study of patients evaluated for BP at a tertiary electrophysiology laboratory between 2017 and 2022. Patients with symptom duration ≥1 month and complete NCS and EMG datasets were included. These datasets were analyzed to determine lesion localization, including trunks, cords, anterior primary rami (APR), and preganglionic involvement. Electrophysiological patterns were compared between traumatic and non-traumatic etiologies. RESULTS: Seventy-eight patients were included (69 males; mean age 31.7 years); 70 (89.7%) had traumatic and 8 (10.3%) had non-traumatic BPs. Pan-plexopathy was the most frequent localization (73.1%), followed by upper trunk involvement. EMG was abnormal in all patients and provided incremental diagnostic yield beyond NCS alone, identifying plexus involvement in 2.6% of patients with normal NCS and detecting APR or preganglionic involvement in an additional 6-9%. Preganglionic and root avulsion patterns were observed exclusively in traumatic cases (8.9%). Apart from proximal lesions in the form of APR and root involvement exclusivity in traumatic BP, electrophysiological patterns overlapped substantially between etiologies. CONCLUSIONS: Pan-plexopathy and upper trunk involvement predominate in BPs. EMG provides critical information beyond NCS alone, particularly for identifying proximal and preganglionic lesions, and remains indispensable for accurate localization.