Ultrasound-guided cervical selective nerve root block A fluoroscopy-controlled feasibility study

Background and Objectives: Reports of intravascular injection during cervical transforaminal injections, even after confirmation by contrast fluoroscopy, have led some to question the procedure's safety. As ultrasound allows for visualization of soft tissues, nerves, and vessels, thus potentially improving precision and safety, we evaluated its feasibility in cervical nerve root injections. Methods: This is a prospective series of 10 patients who received cervical nerve root injections using ultrasound as the primary imaging tool, with fluoroscopic confirmation. Our radiologic target point was the posterior aspect of the intervertebral foramen just anterior to the superior articular process in the oblique view and at the midsagittal plane of the articular pillars in the anteroposterior (AP) view. Results: The needle was exactly at the target point in 5 patients in the oblique view and in 3 patients in the AP views. The needle was within 3 mm in all patients in the lateral oblique view and in 8 patients in the AP view. In the remaining 2 patients, the needle was within 5 mm from the radiologic target. In 4 patients, we were able to identify vessels at the anterior aspect of the foramen, whereas 2 patients had critical vessels at the posterior aspect of the foramen, and in 1 patient, this artery continued medially into the foramen, most likely forming or joining a segmental feeder artery. In both cases, the vessels might well have been in the pathway of a needle correctly positioned under fluoroscopic control.