Beschreibung:
<jats:p>Synovial folds (SFs) are part of the normal anatomy of the Z joints. Although degenerative changes and adhesions have been identified in hypomobile Z joints, putative changes in SFs have not been previously studied. Using an established, IACUC approved, rat model, 3 contiguous segments (L4, L5, L6) were fixed with a specially engineered, surgically implanted, vertebral fixation device. Spinal segments of control rats (n=24 animals, 88 joints) were compared with those of animals with 4, 8, 12, or 16 weeks of fixation (n=16 animals, 54 joints). At the end of the experimental period, deep anesthesia was induced, followed by transcardial perfusion with fixative. Tissue was embedded in paraffin, sectioned, stained, and examined and photomicrographed using bright field microscopy. The number of Z joint quadrants with SFs was determined for each joint (left and right L4/L5 and L5/L6). Average number of quadrants with SFs was calculated for each group. Results: SFs were found in all joints. Significant differences were found among and between groups (ANOVA, p<0.001) with joints of control animals of each time period having larger synovial folds than fixation animals of the same time period (Tukey post hoc, wks: 4, p<0.05; 8, p<0.001; 12, p<0.005; 16, p<0.001). We conclude that hypomobility of rat Z joints results in regression of synovial folds.</jats:p><jats:p>Support: NCMIC administered by FCER (Grant # 97‐10‐18).</jats:p>