Ultrasound-Guided Hydrodissection for Dorsal Scapular Nerve Entrapment: A Technical Report on the Scalene and Scapular Approaches.

Dorsal scapular nerve (DSN) entrapment is a common yet often underdiagnosed cause of chronic interscapular and neck pain. Ultrasound-guided hydrodissection has emerged as a minimally invasive and effective treatment, utilizing fluid to separate the nerve from constricting fascial structures. This technical report provides a detailed, step-by-step guide for two primary approaches to DSN hydrodissection: the proximal (scalene) approach and the distal (scapular) approach. The scalene approach targets the nerve within the middle scalene muscle, its most common site of entrapment, while the scapular approach targets the nerve as it courses deep to the levator scapulae and rhomboid muscles along the medial scapular border. We describe the requisite patient positioning, sonographic anatomy, key landmarks for nerve identification, and the in-plane injection technique for each method. A standardized injectate of 10 mL containing triamcinolone acetonide (40 mg) and lidocaine in saline is used for both. This report serves as a comprehensive technical reference for pain physicians and interventionalists seeking to enhance the precision, safety, and efficacy of ultrasound-guided interventions for DSN entrapment syndrome, a common yet underdiagnosed cause of chronic interscapular and neck pain.