Disclosures: Michael O. Boyd, DO: Nothing to disclose

Case Description: The patient was referred to sports medicine clinic for 2 months of left shoulder pain and weakness. Her symptoms began shortly after a branchial cleft cyst excision. She endorsed left anterior shoulder pain and weakness with flexion and abduction past 30 degrees. Her pain was refractory to meloxicam and two intramuscular corticosteroid injections. She denied paresthesias, shoulder dislocation, trauma or weakness in other parts of the arm. Workup completed at the time of referral was AP and lateral x-rays and MRI of the left shoulder which were negative for pathology. Exam demonstrated subtle atrophy and tenderness to palpation of the left superior trapezius muscle. Left shoulder abduction past 30 degrees required extension of the left shoulder posteriorly and use of accessory muscles to elevate her arm superiorly. Observation of her scapula during range of motion testing revealed a protracted, depressed and medially rotated scapula. She was referred for electrodiagnostic evaluation.

Setting: Tertiary Care, Academic Medical Center, Sports Medicine Clinic and Electrophysiology Lab

Patient: An 18-year-old female student athlete with left shoulder pain and weakness.

Assessment/Results: Nerve conduction studies showed asymmetric spinal accessory nerve amplitudes (1.5 mV on the left and 6.0 mV on the right). Electromyography evaluation of the left trapezius muscle demonstrated normal insertional activity, no spontaneous activity at rest, small polyphasic motor unit potentials, reduced recruitment and interference pattern leading to the diagnosis of spinal accessory mononeuropathy. She was referred to physical therapy and completed 16 weeks of scapular stabilization and shoulder strengthening exercises, which significantly improved her symptoms.

Discussion: Spinal accessory nerve injuries are a known complication in head and neck cancer surgeries, but, to our knowledge, this is the first reported case of spinal accessory nerve injury following branchial cleft cyst excision.

Conclusion: Electrodiagnostic evaluation should be considered in the workup of obscure cases of shoulder pain and weakness.

Level of Evidence: Level V

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PM&R Meeting Abstracts - https://pmrjabstracts.org/abstract/the-cold-shoulder-a-case-report-of-an-unusual-cause-of-shoulder-pain-and-weakness/