Spondylolisthesis, Pars Defect & Stress fracture
Spondylolisthesis with pars defect - …
Repetitive trauma means extension movements of the spine, with lateral flexion, which increase the shearing stress at the pars interarticularis and result in a stress fracture.
Spondylolysis and Spondylolisthesis - OrthoInfo - AAOS
Spondylolysis (spon-dee-low-lye-sis) and spondylolisthesis (spon-dee-low-lis-thee-sis) are separate, yet related conditions. Spondylolysis usually comes first, though not always. The term comes from "spondylo," which means "spine," and "lysis," which means to divide. Spondylolysis is a breakdown or fracture of the narrow bridge between the upper and lower facets, called the pars interarticularis. It can occur on one side (unilateral) or both sides (bilateral) and at any level of the spine, but most often at the fourth or fifth lumbar vertebra (Fig. 2). If spondylolysis is present, then you have the potential to develop spondylolisthesis.
Three stages of injury to the pars interarticularis—the ..
The lytic (subtype a) results from the separation or dissolution of the pars. The incidence of this type of Spondylolisthesis increases from less than 1 percent in children 5 years of age to 4.5 percent in children 7 years of age. The remaining 0.8 to 1 percent increase occurs between the ages of 11 to 16 years, presumably because of stress fractures caused by athletic activity. Extension movements of the spine, with lateral flexion, can increase the shearing stress at the pars interarticularis and result in Spondylolysis.
Many people with spondylolysis and spondylolisthesis never become ..
A unilateral pars defect (spondylolysis) may not demonstrate any degree of slippage; thus, a patient may have spondylolysis without spondylolisthesis. The reverse is also true as in the degenerative-type slips described below.