RESUMEN
BACKGROUND: Stretch-induced spinal accessory nerve palsy has been considered extremely rare, with only a few cases reported. OBJECTIVE: In 357 patients with stretch lesions of the brachial plexus, we investigated the prevalence, course, and surgical treatment of accessory nerve palsy. METHODS: Accessory nerve palsy was ascertained when the patient was unable to shrug the ipsilateral shoulder. Patients underwent brachial plexus reconstruction between 6 and 8 months after trauma. To confirm paralysis, during surgery, the accessory nerve was stimulated electrically. RESULTS: Accessory nerve palsy occurred in 19 of the 327 patients (6%) with upper type or complete palsy of the brachial plexus. Proximal injuries of the accessory nerve accompanied by voice alteration and complete palsy of the sternocleidomastoid and trapezius muscle occurred in 2 patients. Proximal palsy without vocal alterations was observed in 6 patients. Palsy of the trapezius muscle with preservation of the sternocleidomastoid muscle occurred in 11 patients. All 7 patients who demonstrated muscle contractions upon electrical stimulation of the accessory nerve during surgery recovered completely. Patients with surgical reconstruction of the accessory nerve through grafting (n = 2) or repair by platysma motor nerve transfer (n = 2) recovered active shoulder shrugging within 36 months of surgery. Seven of the 8 patients without accessory nerve reconstruction recovered from their drop shoulder and head tilt, but remained unable to shrug. CONCLUSION: If intraoperative electrical stimulation produces contraction of the upper trapezius muscle, no repair is needed. In proximal injuries, the platysma motor branch should be transferred to the accessory nerve; whereas in paralysis distal to the sternocleidomastoid muscle, the accessory nerve should be explored and grafted.