Extracranial spinal accessory nerve palsy following neck surgery: a clinical and electrophysiological study of seven cases

After innervating the sternocleidomastoid muscle, the spinal accessory nerve emerges and down crosses the posterior cervical triangle to innervate the trapezius. At the posterior triangle, the nerve is closely related to local lymph nodes and may be injured by their enlargement or surgical removal. Injury to this nerve is uncommon. Most cases are iatrogenically due to surgical procedures in the posterior cervical triangle, often following lymph nodes biopsies or benign tumors approaches. We present seven eases of post-surgical related spinal accessory nerve injury and discuss its clinical and electrophysiologyeal profiles. The major motor signs were shoulder drop and paresis to mise ann. Pain and sensory complaints were almost universal and most probably due to concomitant injury of cervical plexus cutaneous branches, which are in direct relation to the spinal accessory nerve in the posterior cervical triangle. Lesion type is usually axonotmesis, but varied degrees of compression by cicatricial spurs are observed in some patients. Surgical approach and nerve repair must be considered fur patients with delayed recovery.