"Winged" Eagle's syndrome: neurophysiological findings in a rare cause of spinal accessory nerve palsy. Illustrative cases

Eagle's syndrome (ES) classically describes dysphagia, globus sensation, and otalgia from an elongated and calcified styloid process or stylohyoid ligament. Compression of the spinal accessory nerve (SAN) has not been reported as an associated feature of ES or related variants. The authors describe two cases of an atypical "winged" variant with SAN palsy resulting from compression by a posteriorly angulated or calcified styloid process. Both patients exhibited lateral scapular winging and atrophy of the trapezius and sternocleidomastoid muscles. Electrophysiological studies demonstrated motor unit preservation; therefore, surgical exploration, styloidectomy, and SAN decompression were performed through a transcervical approach. Postoperatively, both patients had improvements in pain and shoulder mobility, the return of muscle strength, and electrophysiological evidence of trapezius reinnervation. Compression of the SAN, which can be identified both clinically and on electrodiagnostic testing, is an atypical finding that can result from a posteriorly angulated or calcified styloid process. This winged variant of ES should be included in the differential for SAN palsy, and a multidisciplinary approach is recommended for assessment and management.