Ultrasound-Guided Lumbar Transforaminal Injections

In Brief Study Design. Preclinical feasibility study. Objective. Evaluation and validation of ultrasound-guided lumbar transforaminal injections. Summary of Background Data. Lumbar transforaminal injections are routinely implemented in the interventional management of spinal radicular pain. Typically, these injections are administered under fluoroscopy or computed tomography. Although radiological guidance provides anatomical precision and accuracy, it is associated with radiation exposure and cannot be performed during outpatient visits or at bedside. Ultrasound-guided techniques have been previously described; however, the methodological generalizability remained unknown and validation against routine fluoroscopy has never been conducted on multiple spinal levels. Methods. We addressed the procedural accuracy of ultrasound-guided lumbar transforaminal injections and proposed anatomically sound approach. Fluoroscopic validation was performed. Results. Of the 50 planned injections, 46 procedures were performed. L5/S1 foraminal access was impossible in 4 cases (8%). Fluoroscopy confirmed the correct foraminal placement in all 46 injections (100%). The contrast-spread pattern was intraforaminal in 42 cases (91.3%) and extraforaminal (nerve root) in 4 cases (8.7%). When intraforaminal pattern was detected on anteroposterior image, lateral fluoroscopy demonstrated ventral epidural flow in all occasions. In 3 cases, intravascular injection was detected (6.5%). Conclusion. Ultrasound-guided lumbar transforaminal injections are accurate and feasible in the preclinical setting. Ultrasound-guided lumbar transforaminal approach may be considered as an alternative to radiological guidance. Development of a safe and reliable technique and its validation are necessary prior to clinical implementation. This study addresses methodology and validation of the ultrasound-guided injections against routine fluoroscopy.