Early histologic changes in lower lumbar discs and facet joints and their correlation

Biomechanical and histologic studies have highlighted the close functional relationship between lumbar discs and their associated facet joints, and it is conceivable that their degenerative changes are interdependent. However , separation of cause from effect remains controversial. Hitherto, no study in humans has correlated the changes histologically. The present study ass essed histologic changes in lower lumbar discs and their associated facet j oints in patients under the age of 40 years using classification systems de veloped for this investigation. A specific objective was to correlate chang es in discs and facet joints. Data from 15 lower lumbar spine specimens wer e obtained. Three parasagittal sections per disc and one section per facet joint were graded histologically. The results were correlated with age, wit hin the functional spinal unit (FSU), and with the adjacent level. Histolog ic changes were found in discs and facet joints from all FSUs. There was no correlation between the age of the subject and the degree of degeneration of the disc or facet joints at either level. The extent of disc degeneratio n at L4/5 correlated significantly with changes at L5/S1 (P < 0.01). There was no correlation between changes in discs and the associated facet joints at either level. The results of the study showed that microscopic changes are seen in the disc and facet joints from an early age and can be quite ma rked in some individuals before the age of 40 years. A correlation of degen erative changes within the FSU could not be established.