The role of lordosis.

A majority of degenerative changes in the vertebral discs, the facet joints or even the interspinous ligaments, as in Baastrup's disease, are probably caused by pressure damage. Among the various causes of overloading, hyperlordosis--alone or in combination with other adjuvant causes--is presumably the most important one. Its detrimental influence is most noticeable in some peculiar situations, where lordosis is the common denominator of malformations of different origins, as, for instance, dorsal and dorsolumbar kyphosis, L4-5 facetarthrosis with L5-S1 spondylolisthesis, and posterior or posterolateral distraction arthrodesis. It is now recognized that arthrodesis in the lumbar spine should be done in normal lordosis or even slight hyperlordosis in order to respect, or even to improve the stress distribution in the mobile segments. After lumbosacral arthrodesis, as well as in common "everyday" low back pain problems, protection of the disks and facet joints from prolonged continuous loading is essential for the prevention of continuing degeneration.