Lumbar facet joint tissue has inflammatory cytokines. However, no reports have shown whether inflammatory cytokines in the facet joint leads to pain. This study was designed to characterize the correlation between inflammatory cytokines released from facet joint tissue and symptoms in degenerative lumbar spinal disorders. The purpose of this study was to seek involvement of inflammatory facet joint for radiculopathy in lumbar spinal canal stenosis with clinical and anatomical studies.
Lumbar facet joint cartilage and synovial tissues in 40 cases of posterior lumbar surgery were harvested to measure tumor necrotizing factor-alpha (TNFalpha), interleukin-1beta (IL-1beta), and interleukin-6 (IL-6) during operation. The visual analogue scale (VAS) and Roland-Morris disability questionnaire (RDQ) were used to examine the correlation between cytokine concentration and symptoms. Coloring agent was injected into facet joints of fresh cadavers to find leakage of pigment from the facet joint into the spinal canal.
Inflammatory cytokines were detected in the joint tissues in the lumbar spinal canal stenosis (LSCS) and lumbar disc herniation (LDH) groups. A positive reaction rate of IL-1beta was significantly higher in the LSCS group than in the LDH group. IL-1beta-positive cases in the LSCS group showed higher VAS scores for leg pain and higher RDQ scores. Intraspinal canal tissues including lumbar nerve root were stained by injection of methylene blue into the facet joints.
IL-1beta in facet joint cartilage in LSCS was associated with leg pain and a decline of quality of life. Inflammatory cytokines produced in degenerated facet joint may leak into the intraspinal space through the lateral part of the ventral facet joint capsule. These results suggest the involvement of inflammatory cytokines in degenerated lumbar facet joints regarding the genesis of pain production.