• Cramer GD

• Immobilization / adverse effects
• Tissue Adhesions / etiology
• Zygapophyseal Joint / pathology

Methods: Using an established rat model, 3 contiguous segments (L4, L5, L6) were fixed with specially engineered, surgically implanted, vertebral fixation devices. Z joints of experimental rats (17 rats, 64 Z joints) with 4, 8, 12, or 16 weeks of induced hypomobility were compared with Z joints of age-matched control rats (23 rats, 86 Z joints). Tissue was prepared for brightfield microscopy, examined, and photomicrographed. A standardized grading system identified small, medium, and large ADH and the average numbers of each per joint were calculated.

Results: Connective tissue ADH were characterized and their location within Z joints described. Small and medium ADH were found in rats from all study groups. However, large ADH were found only in rats with 8, 12, or 16 weeks of experimentally induced intervertebral hypomobility. Significant differences among study groups were found for small (P < .003), medium (P < .000), and large (P < .000) ADH. The average number of medium and large ADH per joint increased with the length of experimentally induced hypomobility in rats with 8 and 16 weeks of induced hypomobility.

Conclusions: We conclude that hypomobility results in time-dependent ADH development within the Z joints. Such ADH development may have relevance to spinal manipulation, which could theoretically break up Z joint intra-articular ADHs.

This abstract is reproduced with the permission of the publisher; full text by subscription. Click on the above link and choose a publisher from PubMed's LinkOut feature.