Variation of facet joint orientation and tropism in lumbar degenerative spondylolisthesis and disc herniation at L4-L5: A systematic review and meta-analysis.

Although degenerative spondylolisthesis (DS) and lumber disc herniation (LDH) are common causes of back pain, the associations between the lumbar facet joint angle orientation and tropism in these conditions are still contentious. The objective of the meta-analysis was to identify the role of facet joint orientation and tropism on the development of lumbar degenerative disease, including DS and LDH. Electronic searches of PubMed and Embase were conducted up to April 2017. P value<0.05 was regarded as significant. Seventeen studies were included in this meta-analysis. Depending on the analysis, patients with DS have more sagittal orientated facet joints compared with control subjects (weighted mean difference [WMD] -10.5, 95% confidence interval [CI] -11.71 to -8.60; P<0.00001). We also found that DS patients have more remarkable facet joint tropism (WMD 1.84, 95% CI 0.77-2.91; P=0.0007). No significant correlation was observed between facet joint angle with LDH. There is a possibility that morphological deformity of facet joints could be associated with accelerated degeneration of stabilizing structures and affect the progress of DS. Our conclusion did not support the correlation between LDH and abnormalities of the facet joint. We tend to assume that the mechanics related to biomechanical changes in LDH disease progress might be more sophisticated.