Healing trabecular microfractures in the bodies of lumbar vertebrae.

The presence of nodular aggregates of woven bone situated on porotic trabeculae has been described in the patella in chondromalacia patellae (Darracott and Vernon-Roberts, 1971) and in the femoral head in osteoarthrosis and rheumatoid arthritis (Todd, Freeman, and Pirie, 1972). The distribution and microstructure of the nodular aggregates indicate that they may represent some form of new bone formation or buttressing effect at sites of trabecular stress (Darracott and Vernon-Roberts, 1971) or callus formation surrounding the sites of trabecular fractures (Todd and others, 1972). The presence of fractures through trabeculae with surrounding callus formed of woven bone has also been described in idiopathic asepticnecrosis ofthe femoralhead (Lagier, 1971). The microstructure and distribution of these trabecular lesions in the patella and femoral head has stimulated us to search for similar lesions in the bodies of lumbar vertebrae, since diffuse or focal osteoporosis is a common finding in this region after the fifth decade, and since it is also clear that this region of the skeleton is constantly subjected to severe mechanical stresses throughout life. The possibility that such lesions could be concerned in the genesis of back pain was also considered when we started this study.