A novel technique of ultrasound-guided nerve root block: anterior compression lateral approach

Conventional posterior ultrasound-guided selective cervical nerve root block (SNRB) often fails to deliver injectate reliably into the neural foramen, while fluoroscopic guidance involves radiation exposure and specialized equipment. We developed a novel anterior compression lateral (ACL) ultrasound-guided approach to provide radiation-free, real-time visualization with improved intraforaminal delivery. This study compared ACL with conventional ultrasound (US) and fluoroscopy (FL) in terms of needle placement accuracy and injectate distribution.

This retrospective single-center cohort study measured needle tip distance from the lateral mass on anteroposterior radiographs. Contrast distribution was classified as foraminal, junctional, or extraforaminal on radiographs and confirmed with axial CT in the US and ACL subgroups. Craniocaudal spread distance was also quantified.

A total of 114 patients with cervical radiculopathy underwent SNRB using FL (n = 56), US (n = 25), or ACL (n = 33). Radiographic intraforaminal distribution occurred in 76.8% of FL, 72.7% of ACL, and 16.0% of US injections (P < 0.0001). Needle tips in US and ACL were positioned more lateral than FL (mean offsets 4.3 ± 6.8 mm and 2.5 ± 3.9 mm vs - 3.5 ± 2.6 mm, respectively). Injectate spread was greater with US (30.8 ± 9.6 mm) and ACL (25.9 ± 15.1 mm) than FL (15.9 ± 10.7 mm) (P < 0.0001). On CT, ACL achieved higher intraforaminal contrast than US (72.7% vs 16.0%, P < 0.0001). No major complications occurred.

The ACL ultrasound-guided approach delivers intraforaminal injectate with accuracy comparable to fluoroscopy while eliminating radiation exposure. It outperforms conventional posterior ultrasound in targeting consistency and offers a precise, accessible option for outpatient cervical SNRB.