Intraneural Ganglion of the Suprascapular Nerve with Asymmetric Branch Recovery and Dual-Site Compression: A Case Report

Introduction: Intraneural ganglion cysts of the suprascapular nerve (SSN) are rare cystic lesions that can lead to shoulder pain, weakness, and muscle atrophy due to nerve compression. They frequently arise secondary to a capsulolabral tear, which allows joint fluid to track into the nerve through the articular branch. Although relatively uncommon, appropriate management is crucial to prevent cyst enlargement and progressive nerve damage. Case Report: We report the case of a 63-year-old woman who presented with a 6-month history of posterior shoulder pain, weakness, and limitation in overhead activities. Magnetic resonance imaging and ultrasound identified an intraneural ganglion cyst at the spinoglenoid and suprascapular notch in association with a superior labrum anterior to posterior lesion, while electromyography (EMG) confirmed a SSN lesion proximal to the branch to the supraspinatus muscle. Conservative management with physiotherapy, cyst aspiration, and corticosteroid injection provided partial pain relief but resulted in cyst enlargement. Follow-up EMG demonstrated partial recovery of the supraspinatus branch but no recovery of the infraspinatus branch. Arthroscopic decompression and labral debridement were performed, preserving the articular branch. Postoperatively, EMG confirmed symmetrical recovery of both the supraspinatus and infraspinatus muscles. Conclusion: This case demonstrates that conservative treatment without addressing the underlying labral tear may allow cyst progression and cause dual-site nerve compression with asymmetric branch recovery. Early recognition, serial imaging, and EMG are essential to guide timely surgical intervention and prevent irreversible denervation. This report also supports Spinner's unifying articular theory.