Spondylolysis is more common in: March 2009

Ans. C: Pars Interaicularis Normally the inferior aiculating fact of each lumbar veebral body lies posterior to the superior aiculating facet of the body below it. If the bony connection between the inferior and superior aiculating facets (pars interaicularis) is defective, the weight of the body may cause the upper veebra, including all of the veebral bodies above it, to slip forward for varying amounts on the body below (spondylolisthesis) The defect in the pars interaicularis is called spondylolysis Spondylolysis is not present at bih but increases in frequency with increasing age. When symptomatic, pain is the most frequent symptom of either spondylolysis or spondylolisthesis There are several different etiologies for spondylolisthesis: Spondylolytic spondylolisthesis is the most common type and results from bilateral defects in the pars interaicularis. Degenerative spondylolisthesis -Most frequent at the L4-L5 level It is not the result of a pars defect but a complex interaction between the disk, facets joints and the ligamentous structures Dysplastic spondylolisthesis-Results from congenital abnormalities of the body and/or facets in the lumbar region such that the alignment of the facets allows spondylolisthesis to occur. The pars may or may not be intact Traumatic spondylolisthesis-Trauma can lead to an acute fracture through a normal pars interaicularis. Conventional radiography in the anteroposterior, lateral and both oblique projections is usually adequate to demonstrate both spondylolysis and spondylolisthesis Spondylolysis appears as a break in the "neck" of the Scottie Dog on the oblique view