We performed facet joint injection to thirty two patients who had chronic low back pain. The mean age of the subjects was 52.8 years. All patients had other mechanical lumbar problems such as herniated intervetebral disc, degenerative spondylosis, spondylo-listhesis, old L1 compression fracture and all had been refractory to the usual conservative treatment at least for 6 weeks.

Facet joint injection was done under fluoroscopic guide. Lidocane 1 mL, Depomedrol 1mL, and contrast media(Ultravist^Ⱂ) 1mL were injected into the facet joint cavity and were extravaginated into the extracapsular tissue.

Pain assessment was carried out with 10cm visual analog scale(VAS) before the injection, and the presence or absence of immediate pain relief after the injection. Twenty patients followed-up for 3 months and the severity of pain was asked(A: completely relieved, B: improved, C: not changed, D: aggravated).

Immediate pain relief was present in 22(68.7%) out of 32 patients. 3 months later, pain was relieved completely or improved in 10 patients(50%). The similar good result was shown in 9 patients who had confirmed the lumbar herniated intervetebral disc.

We assumed the facet joints were responsible for 20∼25% of chronic low back pain. Facet joint injection is easy to perform and a safe procedure. We could expect good results in 50% of subjects regardless of combined lumbar problems.