Physical Therapy Management of Scapular Dyskinesis Due to Spinal Accessory Nerve Palsy Secondary to Neuralgic Amyotrophy: A Case Report.

This case report describes a rare clinical presentation of spinal accessory nerve (SAN) palsy secondary to neuralgic amyotrophy and discusses physical therapy differential diagnosis, interventions, and outcomes. The patient was a 37-year-old left-hand-dominant Caucasian male who presented to physical therapy with right-sided neck and shoulder pain and limited right shoulder overhead movement. Examination identified trapezius atrophy, weakness, compensatory scapular protraction during shoulder flexion, and a positive modified Scapular Assistance Test. Physical therapy interventions included a multimodal approach with therapeutic exercise focused on scapular stabilization and shoulder strengthening, as well as manual therapy interventions including dry needling, thoracic manipulation, elastic therapeutic taping, scapular stretching, and mobilizations with movement to reduce pain and facilitate improved trapezius activation. The patient was seen for ten sessions over four months, with significant improvement in right shoulder flexion active range of motion from 125° to 155° within four weeks, ultimately achieving 165°. He also demonstrated improvements in shoulder strength but continued to exhibit trapezius weakness. Final outcome measures were mixed, with improvement on the Global Rating of Change (GRC) scale by +5, indicating "quite a bit better" and meeting the threshold for meaningful improvement, and improvement on the Patient-Reported Outcomes Measurement Information System (PROMIS) self-efficacy subscale by 4 points, from 37 to 41; however, his PROMIS physical function score declined from 46 to 31. Physical therapists should be aware of neuralgic amyotrophy affecting the SAN as a rare cause of scapular dyskinesis. Early conservative management with physical therapy using a multimodal approach, including manual therapy, was associated with rapid restoration of shoulder flexion range of motion and improvements in strength and pain management in this case.