Ultrasound‐Guided Cervical Periradicular Steroid Injection for Cervical Radicular Pain: Relevance of Spread Pattern and Degree of Penetration of Contrast Medium

Background and Objectives. Ultrasound‐guided cervical periradicular steroid injection (US‐CPSI) is an attractive alternate to conventional C‐arm guided transforaminal epidural injection for treatment of cervical radicular pain. We compared the technical differences and clinical outcomes between these two techniques. Methods. Following ultrasound‐guided needle placement, the extent of contrast media spread and the degree of tissue penetration were monitored by real‐time fluoroscopy at the time of cervical periradicular injection in 59 patients. The spread pattern was judged to be medial foramen (medial bisector of foramen), lateral foramen (lateral bisector of foramen), or extraforaminal. The degree of tissue penetration was classified into periradicular, pararadicular, and intramuscular based on the penetration characteristics. Ultrasonographic images were categorized into crescent, perineuronal protruding, and intramuscular types. These groups were then correlated with clinical outcomes. Results. The actual distance between the ultrasound‐guided needle position and fluoroscopic target point was 1.9 and 2.3 cm in the oblique and anteroposterior view, respectively. Despite a difference in ultrasound and fluoroscopic end points, contrast dye spread was found to reach lateral foramen in 53%, medial foramen in 34%, and extraforaminal in 13% of the subjects. Analysis of postprocedural pain reduction (PPPR) showed significantly the better outcomes in periradicular and pararadicular penetration, medial and lateral, and crescent and perineural protruding type without subgroup differences than intramuscular penetration, extraforaminal spread, and ultrasonographic images of intramuscular type (P