Impairment of upper trapezius branch of the spinal accessory nerve during bypass grafting: a stretch injury?

Internal jugular vein catheterization has been implicated in spinal accessory nerve (SAN) injuries after coronary artery bypass grafting (CABG). Stretch injury due to prolonged positioning during CABG has also been proposed as another mechanism of injury. Herein we describe a male patient with left shoulder pain and abduction difficulty following CABG, who displayed electromyographic abnormalities confined to the left upper trapezius muscle. Internal jugular vein catheterization had not been performed during surgery. Although unusual, the possibility of upper trapezius muscular branch paralysis should be considered in patients with shoulder pain or weakness after CABG.