Normal and pathologic anatomy of the lumbar root canals.

Eighty-three degenerated human lumbar spines (274 segments) were frozen in situ, some after injection of contrast medium into the arteries or after functional positioning. No single orthogonal plane ideally displays the complex three-dimensional relationships in the long osseoligamentous lumbar root canals; detailed anatomic images were therefore obtained in axial, sagittal or coronal planes with a surface cryoplaning technique. Typical degenerative changes included bulging of the intervertebral discs, retropulsion of annulus fibrosus remnants, and the formation of sclerotic, circumferential ridges around the vertebral endplates. Osteoarthritic facet joints exhibited osteophytosis of the superior articular process, cartilage erosion, degeneration and buckling of the capsular ligamentum flavum, effusion, hemarthrosis, and derangement of meniscoid synovial folds. On extension and rotation there was significant encroachment on the nerve root complex and radicular vessels; the importance of the segmental blood circulation is discussed.