426 - Dorsal Scapular Nerve Injury After Neck Manipulation Resulting in Scapular Winging: A Case Report

Case Diagnosis: Dorsal scapular nerve injury resulting in scapular winging.

Case Description: A 54-year-old male presented after two months of right shoulder pain with associated weakness, decreased range of motion (ROM), and pain with overhead activities following cervical chiropractic manipulation. Physical exam revealed right medial scapular winging with flexion and abduction. Right shoulder strength was 5/5 throughout except for 4/5 flexion and abduction. Cervical MRI showed C5-C6 right neural foraminal narrowing. Brachial plexus MRI was unremarkable. Despite three months of conservative management with physical therapy, the patient reported increasing pain and minimally improved ROM. Nerve conduction studies and electromyography at 6 months and 10 months showed symmetric spinal accessory responses and chronic denervation of the right rhomboid major, suggesting chronic right dorsal scapular neuropathy. Further management included right subacromial bursa injection with triamcinolone 40mg/mL, providing 80% pain relief.

Discussions: Scapular winging is abnormal scapular motion due to an imbalance of the periscapular muscles. It is most commonly due to a long thoracic nerve or spinal accessory nerve injury. However, a rare cause of scapular winging can be due to dorsal scapular nerve injury. The dorsal scapular nerve originates from the C5 nerve root and innervates the rhomboid major, rhomboid minor, and levator scapulae muscles. Previous literature mentions dorsal scapular nerve injury from repetitive overhead movements, traction, trauma, or a hypertrophied middle scalene muscle. Chiropractic manipulation applies force and traction to the cervical region, potentially leading to brachial plexus injury. While brachial plexus injuries after manipulation have been documented, there has been no reported dorsal scapular nerve injury.

Conclusions: Although rare, dorsal scapular nerve injury should be included in the differential diagnosis for a patient presenting with scapular winging, shoulder pain, and decreased ROM, especially after cervical chiropractic manipulation.