Optimum Sonoanatomical Approach for Selective Cervical Nerve Root Block: Evaluation of Three Different Needle...

To identify the safest approach for selective cervical spinal nerve block (SCSNB) using sonoanatomic evaluation of spinal nerves (SNs) and adjacent vascular structures.

This study included 50 healthy volunteers and 7 cadavers. In volunteers, C5-C7 SNs were evaluated using ultrasound. Three virtual needle trajectories posterior-to-anterior (P-A), anterior-to-posterior (A-P), and lateral-to-medial (L-M) were assessed within a region of interest. Cadaveric dissections examined morphometric relationships between the vertebral artery (VA), ascending cervical artery (ACA), deep cervical artery (DCA), and SNs.

Vascular structures increased from C5 to C7 (P < 0.001), and the L-M trajectory contained fewer vessels than the A-P and P-A trajectories (P < 0.001). Cadaveric findings demonstrated caudal increases in SN thickness and arterial diameters, with the VA, ACA, and DCA positioned closer to spinal grooves at lower levels.

Lower cervical levels show increased vascular density and vessel proximity to SNs. The L-M trajectory has the fewest vessels and appears safest for SCSNB. The L-M trajectory demonstrated the lowest vascular density and may represent a relatively safer anatomical corridor for SCSNB; however, its clinical performance should be confirmed by future interventional studies.