Abstract

Spondylolysis and spondylolisthesis are two conditions that directly involve changes in the vertebra. Spondylolysis is defined as a defect in the pars interarticularis, the region of the lamina between the superior and inferior articular facets. Progression of the defect can result in spondylolisthesis, which is defined as a subluxation or 'slippage' of two adjacent vertebrae. In the low back it occurs most commonly at the lumbosacral level; next in frequency is spondylolisthesis of the fourth lumbar vertebra on the fifth. To provide the reader with information about the aetiology and anatomical consideration of spondylolysis and spondylolisthesis type. Spondylolisthesis has recently been classified by Wiltse and others into five types based on the suspected aetiology; dysplastic, isthmic, degenerative, posttraumatic, pathologic and postsurgical. Of these five types, isthmic spondylolisthesi and degenerative spondylolisthesis, both of which are frequently associated with low back and lower limb pain.

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