Management of iatrogenic injury to the spinal accessory nerve

Spinal accessory nerve injury results in a debilitating shoulder dysfunction. The trapezius is a major suspensory muscle of the shoulder girdle, and paralysis results in chronic pain and debility from disruption of synchronous scapulohumeral rhythm. This injury usually follows a simple posterior triangle lymph node biopsy and is treatable if appropriate measures are taken in a timely fashion. A major pitfall in early management is either failure to recognize or acknowledge the injury or hoping that it will resolve with conservative treatment. Variation of innervation of the trapezius alters clinical presentation and can make diagnosis difficult. We present a series of six patients with iatrogenic spinal accessory nerve injury following a neck node biopsy. Pain was the most common presenting symptom, and a loss of sustained abduction was the most common physical sign. Three patients had a primary nerve repair and the other three patients had nerve grafting. Maximum recovery time ranged from 4 to 10 months. All patients had varying degrees of recovery of motor function, and all six patients were 100 percent painfree. An algorithm for the management of this distressing condition emphasizes the importance of early referral and highlights the pitfalls in making an accurate diagnosis. Whereas conservative therapy is less predictable and needs careful selection, it also runs the risk of delaying a more effective surgical management. Early operative intervention is more definitive and has the best functional results. Prevention is key and is best achieved by avoiding unnecessary biopsies of the posterior triangle lymph node. When operating, knowledge of posterior neck anatomy and judicious use of the bipolar cautery and magnifying loupes arc essential in preventing this problem.