Ultrasound-guided lumbar medial-branch block: a clinical study with fluoroscopy control

For diagnostic lumbar medial-branch blocks, fluoroscopic guidance is considered mandatory, but this technique comes with radiation exposure. The clinical feasibility of the ultrasound-guided lumbar medial-branch block has been demonstrated. We evaluated the success rate and validity of this new method by use of fluoroscopy controls in patients previously diagnosed with lumbar facet joint-mediated pain.

In 20 patients, 101 lumbar medial-branch blocks were performed under ultrasound guidance. The target point was the groove at the cephalad margin of the transverse process adjacent to the superior articular process. C-arm fluoroscopy was performed afterward to confirm the needle position. Pain scores were assessed by use of visual analog scale (VAS 0 to 100).

All 101 needles were placed in the correct lumbar segment. Ninety-six of the 101 needletips were in the correct position with a success rate of 95%. Two needles were associated with intravascular spread of the contrast dye. VAS score was reduced from 52 to 16 after the block.

Ultrasound-guided lumbar medial-branch blocks can be performed with a high success rate. However, to be completely independent from fluoroscopy controls, this technique requires further studies regarding the detection of intravascular spread.