Ultrasound-Guided Lumbar Nerve Root Hydrodissection: Fluoroscopy-Assisted Evaluation of Injectate Distribution and Feasibility.

Introduction: Selective nerve root block is commonly performed under fluoroscopy, but reports of ultrasound (US) guidance remain limited. Although hydrodissection has shown favorable outcomes in peripheral nerves, few studies have evaluated the lumbar nerve root. Therefore, we aimed to evaluate the injectate distribution, reproducibility, safety, and clinical efficacy of US-guided hydrodissection of the lumbar nerve root (US-HNR) using fluoroscopic assistance. Methods: US-HNR was performed in 46 patients with lumbar radiculopathy between January and September 2025. A standardized injectate (contrast agent 3 mL, saline 6 mL, and lidocaine 1% 1 mL; total 10 mL) was administered. Distribution was classified into four types under fluoroscopy. The Numerical Rating Scale (NRS), Oswestry Disability Index (ODI), and patient satisfaction were evaluated pre- and postprocedurally. Results: Contrast evaluation was possible in 40 patients. Distribution patterns were localized within the periradicular region of the target nerve root in 30%, ipsilateral epidural in 38%, contralateral epidural in 25%, and contralateral nerve root in 8%, suggesting localized spread in one-third of cases. NRS improved significantly from 7.1 to 5.0 at 1 week, 4.2 at 1 month, and 3.8 at 3 months (all Conclusions: US-HNR was safe and feasible, avoiding radiation and direct nerve puncture. This simple technique showed favorable clinical outcomes and may represent a promising treatment for lumbar radiculopathy.