Paralysis of the trapezius muscle: evaluation and surgical management.

Background: Paralysis of the trapezius muscle most commonly results from iatrogenic injury to the spinal accessory nerve.

Methods: The clinical presentation and physical examination findings of trapezius palsy have been well characterized, but unfortunately the diagnosis of this condition is oftentimes missed or delayed, sometimes leading to unnecessary surgery on the rotator cuff or tendon of the long head of the biceps.

Results: The diagnosis can be confirmed using electromyography with nerve conduction studies. Although nonoperative treatment may help some patients with temporary neurapraxia of the spinal accessory nerve, nerve repair with or without nerve grafting should be performed soon for patients suspected of a nerve transection. Nerve transfers can be considered within the first year after the injury when nerve repair and grafting cannot be completed. For chronic trapezius palsy, transfer of the levator scapulae and rhomboids has been refined and represents a very successful surgical procedure. Rarely, scapulothoracic arthrodesis is considered for individuals with failed tendon transfers or multiple nerve involvement.

Conclusion: Trapezius palsy is oftentimes missed. An accurate diagnosis allows consideration of various treatment modalities that have been reported to provide good outcomes for properly selected patients.