ANATOMY IN ASYMPTOMATIC LUMBAR FACET JOINT ARTHROSIS

The facet joints are the only synovial joint of spine and undergo osteoarthritic changes referred to as facet joint arthrosis (FJA). The arthrosis is akin to arthritic changes in any other synovial joint of the body and may manifest as back pain or may remain asymptomatic throughout life. The causes for pain manifestation in FJAare manifold but there is paucity of literature in defining reasons to remain asymptomatic even with a deranged pathology at the joint. Thus the aim of the study was to assess the prevalence of asymptomatic FJA and define its relation with respect to age, gender and vertebral level on CT evaluation and discuss the pertinent anatomy around each spinal motion segment which prevents manifestation of pain.Material & Methods: A total of 100 asymptomatic subjects were selected on basis of a low back pain questionnaire within age range of 20-70 years, reporting to radiology department for CT abdomen. The individualswere categorized as per the following age groups; 20-35yrs as young; 36-50 as middle and 51-70 as old age groups. All five lumbar vertebral levels with their facet joints were analysed for evidences of degenerative grades and their severity, in total selected subjects. The images obtained were further assessed on image analysissoftware for distribution as per the age-groups, gender and prevalence with respect to vertebral level.Results: A total of 136 (27.2%) levels in 43(43%) spines were found to have FJA. The highest prevalence (43.3%) of asymptomatic FJA was observed in the middle age group with involvement of multiple spinal motion segments and with grade 4 severity.Conclusion: Prevalence of severe grades of asymptomatic FJA in middle age group suggests the possible role of certain muscle groups in maintaining an appropriate posture in spite of on-going degenerative processes.