Surgical treatment of low back pain in spine instability.

Spinal instability is a loosely used term resulting from a variety of traumatic, developmental, neoplastic, hereditary, and degenerative insults to the axial skeleton. As defined by White and Panjabi, lumbar instability would imply the loss of the spine's ability, under physiological loads, to maintain its patterns of displacement so as to avoid neurologic deficits, incapacitating deformity, and intractable pain. Although from a strict engineering standpoint, the concept of load and deformation is valid, it is not at all known what type of movement or what magnitude of movement is responsible for low back pain. In light of these considerations, the author would define instability as either acute or chronic. Acute mechanical instability would result from those conditions such as fracture, tumor infiltration, infection, postlaminectomy, and certain congenital defects where a small change in loading or deformation could lead to permanent vertebral displacement with fixed deformity and/or neurologic damage. Chronic instability would result from those low back disorders that lead to progressive deformity over a period of years, often producing back pain from degenerative osteoarthritis, and central as well as foraminal stenosis. These disorders would include lumbar scoliosis, kyphosis, and spondylolisthesis, either isthmic or degenerative type. In those situations associated with more chronic instability, the relationship of low back pain is not always discernable even with provocative discography or magnetic resonance imaging. The surgical treatment of low back pain associated with these spinal instabilities depends on the etiology of the conditions defined. Acute traumatic injuries are best managed by posterior segmental instrumentation. At the level of the upper lumbar spine, a combined approach may be desirable to support anterior column deficiency.(ABSTRACT TRUNCATED AT 250 WORDS)