Ultrasound-guided cervical selective nerve root injections: a narrative review of literature

Background/Importance Ultrasound (US)-guided cervical selective nerve root injections (CSNRI) have been proposed as an alternative to fluoroscopic (FL)-guided injections. When choosing US guidance, the proceduralist should be aware of potential issues confirming vertebral level, be clear regarding terminology, and up to date regarding the advantages and disadvantages of US-guided CSNRI. Objective Review the accuracy and effectiveness of US guidance in avoiding vascular puncture (VP) and/or intravascular injection (IVI) during CSNRI. Evidence Review Queries included PubMed, CINAHL and Embase databases from 2005 to 2019. Three authors reviewed references for eligibility, abstracted data, and appraised quality. Findings The literature demonstrates distinct safety considerations and limited evidence of the effectiveness of US guidance in detecting VP and/or IVI. As vascular flow and desired injectate spread cannot be visualized with US, the use of real-time fluoroscopy, and if needed digitial subraction imaging, is indicated in cervical transforaminal epidural injections (CTFEIs). Given the risk of VP and/or IVI, the ability to perform and to retain FL images to document that the procedure was safely conducted is valuable in CTFEIs. Conclusion US guidance remains to be proven as a non-inferior alternative to FL guidance or other imaging modalities in the prevention of VP and/or IVI with CTFEIs or cervical selective nerve root blocks. There is a paucity of adequately powered clinical studies evaluating the accuracy and effectiveness of US guidance in avoiding VP and/or IVI. US-guided procedures to treat cervical radicular pain has limitations in visualization of anatomy, and currently with the evidence available is best used in a combined approach with FL guidance.