Carotid endarterectomy (CEA) is one of the more commonly performed surgical procedures in North America. The number of CEAs done will probably increase over the next few years because recent studies have shown beneficial effects of CEA in both symptomatic and asymptomatic carotid s t e n o ~i s . ~-~~" ~' ~ Cranial nerve injury is a frequent problem during CEA; however, spinal accessory nerve ( S A N ) injury is rarely d e s ~r i b e d . ' ~. ~~
To increase awareness of this disabling complication, we present 2 cases of S A N injury.
CASE ONE
A 66-year-old man had a right CEA for transient ischemic attacks. The carotid bifurcation was found to be high during the surgery. Postoperatively, the patient developed pain in the right shoulder and inability to raise his arm above the horizontal plane. When seen 5 months after CEA, he had drooping of the right shoulder along with wasting of the upper trapezius muscle. The patient was unable to abduct his right arm fully. Electrodiagnostic study at that time showed symmetrical latencies (2.9 ms) to the upper trapezius on stimulation of the spinal accessory nerves. The amplitude of the compound muscle action potential (CMAP) was reduced (0.4 mV) on the right side as compared to the left (6.3 mV). Concentric needle electromyography (EMG) of the right upper, middle, and lower trapezius showed 2+ fibrillation potentials and a few large motor units