Prospective evaluation of the safety of ultrasound-guided cervical medial branch blocks using the in-plane technique

Background: While fluoroscopic guidance is currently the imaging standard for cervical medial branch blocks (CMBBs), ultrasound guidance (USG) offers several potential safety advantages such as real-time needle visualization and the ability to detect and avoid critical soft tissue vascular or neural structures. However, no large-scale trials have examined the safety of USG for CMBB.

Methods: Five hundred patients undergoing 2308 individual block levels were recruited using a prospective cohort design, and blocks were performed in an outpatient office setting using an in-plane USG technique. Primary outcomes included immediate block-related complication, as well as delayed occurrences, in the following 2 weeks. Vascular structures adjacent to the target area, as well as the occurrence of vascular breach, were recorded.

Results: Three minor immediate complications were noted (two subcutaneous hematomas, one vasovagal reaction) comprising 0.13% of blocks (0.03% to 0.38%; 95% two-sided CI), and no delayed events were recorded (0% to 0.16%; 97.5% one-sided CI). Blood vessels were detected and avoided in 8.2% of blocks, and vascular breach was noted in 0.52% of blocks (0.27% to 0.91%; 95% two-sided CI).

Conclusion: When performed using an in-plane technique by experienced operators, USG CMBB was found to be safe, with rare minor immediate complications and no further adverse event reported in the following 2 weeks.

Trial registration number: NCT04852393.