Novel Ultrasound-Guided Bilateral Simultaneous Hydrodissection of the Cervical Sympathetic Chain and Vagus Nerves: A Detailed Technical Description With Anatomical Correlation

The vagus nerve and cervical sympathetic chain regulate autonomic function and are implicated in chronic pain and post-viral autonomic syndromes. Hydrodissection with 5% dextrose is established for peripheral nerves, but simultaneous ultrasound-guided hydrodissection of both cervical autonomic nerves has not been described. We describe a reproducible ultrasound-guided technique for bilateral simultaneous hydrodissection of the cervical sympathetic chain and vagus nerves using 5% dextrose without local anesthetic. The procedure uses a high-frequency linear transducer at C6-C7 and an in-plane lateral 25-gauge needle approach, performing the deeper sympathetic chain hydrodissection first (prevertebral fascia superficial to the longus colli), followed by vagus nerve hydrodissection within the carotid sheath. Injection is performed slowly (12-18 minutes per side) to permit full delivery and patient comfort. We report procedural outcomes in 10 patients (30 sessions) treated for post-COVID-related autonomic dysfunction. All procedures were completed successfully. Total injectate was 60 mL of 5% dextrose per side (approximately 30 mL for the sympathetic chain and 30 mL for the vagus nerve). The deep-to-superficial sequence preserved sonographic visualization and avoided air-bubble artifact. No procedural complications occurred (including bradycardia, hypotension, voice changes, dysphagia, hematoma, or infection). At a minimum 12-month follow-up, patients maintained clinical improvement without additional interventions. Ultrasound-guided bilateral simultaneous hydrodissection of the cervical sympathetic chain and vagus nerves with 5% dextrose is technically feasible and well tolerated. A deep-to-superficial injection sequence and very slow administration optimize visualization and delivery. Detailed clinical outcomes are presented separately.