[Lower trunk brachial plexopathy due to hematoma following median sternotomy: a case report]

We present the case of an 81-year-old woman who underwent aortic valve replacement and coronary artery bypass surgery by median sternotomy. Following the operation, she experienced distal muscle weakness in her left upper limb and numbness in the medial part of her left forearm and palm. Nerve conduction study revealed low amplitudes of her left ulnar compound muscle action potential (CMAP) and sensory nerve action potential (SNAP), radial CMAP, and medial antebrachial cutaneous SNAP. Needle electromyography showed denervation potentials in the extensor digitorum communis and abductor pollicis brevis. CT and MRI showed a left first rib fracture and a hematoma nearby. Short-T1 inversion recovery image (STIR) showed a high-intensity area in the left root of C8. Based on these findings, we diagnosed the patient with lower trunk brachial plexopathy due to hematoma.