The purpose of this study is to compare using oblique fluoroscopic angle has any advantage in reducing the incidence of vascular punture and technical easiness during lumbar medial branch block

In previous report, the use of oblique fluoroscopic angle during S1 transforaminal injection demonstrated technical easiness and reduced intravascular injection incidences. For the procedure lumbar medial branch block, both anteroposterior and oblique fluoroscopic angle are possible. Usually, which approach method to use is determined according to the physician's preferences.

The final target for lumbar medial branch block is the junction betweeen superior articular process and transverse process. This target can be easily confirmed under the scotty dog appearance. If we use oblique fluoroscopic angle, this approach (30 degree) can make scotty dog appearance more visible so that physician can identify bony landmark more easily for lumbar medial branch block. For beginners, oblique fluoroscopic approach seems to provide more advantages in identifying bony landmark. However, it is uncertain whether this approach can provide technicaL easiness and reduce the intravascualr injection incidences.

Inclusion Criteria:

• facet joint arthropathy

Exclusion Criteria:

• allergy to local anesthetics or contrast medium
• pregnancy
• spine deformity
• neurologic abnormality