Acessory nerve function after surgical procedures in the posterior triangle.

Seventeen patients who had undergone surgical procedures in the posterior triangle of the neck were examined between one day and four years after operation. Eleven patients were studied with electromyography. Clinical and electromyographic evidence of 11th cranial nerve paresis was present in 12 patients. Partial nerve injuries and entrapments, as suggested by delayed symptoms and incomplete denervation on electromyographic studies, were frequent. Physiotherapy was effective in restoring a satisfactory, although in many cases an incomplete, return of function. The spinal accessory nerve appears to be vulnerable to injury despite careful preservation during surgical dissection.