The validation of ultrasound-guided lumbar facet nerve blocks as confirmed by fluoroscopy

Abstract

Study design: This is a prospective study.

Purpose: To develop a methodological approach for conducting ultrasound-guided lumbar facet nerve block by defining essential ultrasound-guided landmarks in order to assess the feasibility of this method.

Overview of literature: The current role of ultrasound guidance for musculoskeletal intervention treatments has been reported upon in previous literature.

Methods: Ultrasound-guided facet nerve block was done in 95 segments for 50 patients with chronic back pain by facet arthropathy. After the surface landmarks of the spinous process and iliac crest line were confirmed, longitudinal facet views were obtained by a curved array transducer to identify the different spinal segments. The spinous process and facet joint with transverse process were delineated by transverse sonograms at each level and the target point for the block was defined as lying on the upper edge of the transverse process. The needle was inserted toward the target point. After a contrast injection, the placement of the needle and contrast was checked by fluoroscopy.

Results: Eighty-seven segments (91.6%) could be guided successfully to the right facet nerve block by using ultrasound. After fluoroscopic control, 8 needles had to be corrected because of problems with other segments (3 cases) and lamina placements (5 cases). For the 42 patients who underwent successful block by ultrasound, however, the mean visual analogue score for back pain was improved from 6.2 ± 0.9 before the block to 4.0 ± 1.0 after the block (p = 0.001).

Conclusions: Ultrasound-guided longitudinal facet view and the surface landmarks of the spinous process and iliac crest line seems to be a promising guidance technique for the lumbar facet nerve block technique.

Keywords: Lumbosacral region; Nerve block; Ultrasonography.

Figures

Fig. 1

Marking of L4-5 spinous process and iliac crest as surface anatomical landmarks.

Fig. 2

Longitudinal facet views were obtained by curved tranducer to identify the different spinal segments (A), longitudial facet view by ultrasound showed L3-4, L4-5, and L5-S1 facet joints (B).

Fig. 3

Needle insertion between the superior articular process and on the upper edge of the transverse process. SP: Spinous process, FJ: Facet joint, TP: Transverse process.

Fig. 4

The fluoroscopy revealed correct insertion of needle at the facet joint (A) and the wrong insertion of needles (B).