Evaluation of the effects of facet joint morphologic variations on chronic low back pain

Low back pain (LBP) is one of the reasons among the musculoskeletal system disorders that leads to patient complaints and constrains from social life. 80% of the people suffer from LBP in one part of their lives. There are many factors present in the etiology of LBP. The aim of this study is to classify morphological types of anatomical variations of facet joints and to evaluate the effect of facet joint orientation angles on the overall pain status (VAS) and overall functional status (Oswestry Disability Index) of the patients with chronic LBP. Two-hundred and five patients that are consistent with the inclusion criteria diagnosed as nonspecific chronic LBP that those were under 65 years old were included in the study. Computed tomographic scan of the lumbar spine was conducted with an objective to classify anatomical variations of the facet joints. The measurement of facet joint orientation angles and determination of facet types at L4 and L5 vertebras of the patients has been conducted. Facet joint morphological types are categorized as curved and flat. The patients who have different types in right facet and left facet joints at the same vertebra level have been noted as asymmetrical. Measurement of spinal canal area and the vertebra corpus area of the patients has been performed to determine whether the patients have anatomic stricture at the L4 and L5 vertebra levels. The ratio of multiplicated sagittal and transverse diameters of spinal canal to multiplicated sagittal and transverse diameters of the corpses has been calculated. The calculated value was accepted as a representative of the spinal canal area. VAS has been used for the general pain level evaluation of the patients. Oswestry disability Index has been used for functional evaluations. The patients who had curved type of facet joints had also sagittal orientation. It had been determined as mostly curved at the level of L4, whereas it had been observed mostly flat type at the level of L5. Facet joint orientation angles show mostly sagittal orientation at L4 vertebra level and show mostly coronal orientation at L5 vertebra level. More functional insufficiency and greater pain level had been detected in the patients whose facet joint orientation angle shows sagittal orientation that was statistically significant (p<0.05). As the result, facet joint morphological types and anatomical orientation angles may affect general pain and functional status of the patients. Key Words: Facet, Anatomical Variations, Chronic Low Back Pain, Oswestry Disability Scale