Working Diagnosis:
Lateral Scapular Winging secondary to Spinal accessory Nerve Injury and Trapezius muscle atrophy secondary to Spinal accessory nerve injury

Treatment:
Patient was referred for physical therapy 3 times a week for 4 weeks, and then 2 times a week for another 2 months. Therapy focused on shoulder range of motion and isometric exercises focused on the trapezius, sternocleidomastoid and cervical musculature.

Home scapular, rotator cuff, trapezius and cervical strengthening exercises were also provided to patient.

Outcome:
At 6-month follow-up, the patient's range of motion had returned to pre-injury levels and pain had resolved.

The patient did not return to playing football this season, which was his only sport. He returned to weightlifting and cardiovascular conditioning without difficulty. Patient likely was cleared to play football for the following season. The patient was also cleared to participate in off-season workouts as tolerated as well.

Author's Comments:
The spinal accessory nerve (Cranial Nerve XI) descends along the internal carotid artery and innervates the sternocleidomastoid and trapezius muscles.

The primary complaint seen with injury to the spinal accessory nerve is pain and weakness of the shoulder. Pain may radiate to the upper back, neck, or ipsilateral arm. Pain is typically more prominent with lifting objects overhead. On examination, the affected shoulder may be in a lower position (drooping) compared to the normal shoulder, with or without trapezoidal atrophy.

It is important to differentiate lateral scapular winging from medial scapular winging, the latter of which is caused by weakness of the serratus anterior muscle and commonly caused by damage to the long thoracic nerve.

Serratus anterior muscle palsy typically recovers well with conservative management. Paralysis of the trapezius, however, rarely however improves with such treatment. In many cases, exploration and nerve repair yields better results. This case signifies the importance of differentiating between medial and lateral scapular winging.

Editor's Comments:
Spinal accessory nerve injuries are uncommon, and many are iatrogenic in nature after a surgical procedure. They are typically associated with neuropathic pain, significant reduction in shoulder range of motion, shoulder drooping, and scapular winging. Workup should include history, physical examination, and electrodiagnostic studies. This case demonstrated a young patient who responded well to conservative management; those who fail conservative treatment after 1 year are candidates for surgical intervention.

References:
Park SB, Ramage JL. Winging of the Scapula. [Updated 2023 Mar 13]. In: StatPearls [Internet]. Treasure Island (FL): StatPearls Publishing; 2024 Jan-. Available from: https://www.ncbi.nlm.nih.gov/books/NBK541005/

Bordoni B, Reed RR, Tadi P, et al. Neuroanatomy, Cranial Nerve 11 (Accessory) [Updated 2023 Jul 17]. In: StatPearls [Internet]. Treasure Island (FL): StatPearls Publishing; 2024 Jan. Available from: https://www.ncbi.nlm.nih.gov/books/NBK507722/

Wiater JM, Bigliani LU. Spinal accessory nerve injury. Clin Orthop Relat Res. 1999 Nov;(368):5-16. PMID: 10613148.

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