[Etiologies of lumbago].
There are numerous etiologies to low back pain. Even if the degenerative origin is the most frequent one, other possible aetiologies have to be kept in mind. Inflammatory low back pain is encountered in the young patient, appearing at night and can be associated with extra-spinal symptoms (e.g. psoriasis, M. Reiter, etc.). The lumbar spine is rarely involved in chronic polyarthritis. In case of tumors, the metastasis is the most frequent cause whereas the plasmocytoma is the most frequent primitive bone tumor of the spine. Infectious diseases can be of hematogenous origin or by direct iatrogenic inoculation. Surgical treatment is indicated in case of inefficient medical treatment or if there is a risk of neurologic compromise or instability. Low back pain of metabolic origin is related to osteoporosis. Pain is secondary to vertebral compression fractures which makes it come close to post-traumatic low back pain caused by static disorders. Finally, in most cases low back pain is has a degenerative origin. The degenerative disease is dominated by the disc degeneration, primum movens of the degenerative disease. Alteration of the mechanical properties of the disc leads to degenerative arthritis in the intervertebral joints by modifying their motion pattern. These changes can lead to osteophytes which can, together with the narrowing of the disc space lead to a narrowing either of the foramen intervertebrale or the spinal canal (acquired lumbar stenosis). Treatment is nonoperative first except in urgent situations (conus cauda syndrome, disc hernia with paresia).