Isthmic Spondylolisthesis is most commonly at which spinal level?

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Multiple Choice

Isthmic Spondylolisthesis is most commonly at which spinal level?

The level most commonly involved is the L5 level at the L5–S1 junction. Isthmic spondylolisthesis happens when a defect in the pars interarticularis allows forward slipping of the vertebra. The L5–S1 junction bears the greatest anterior shear forces because of the lumbosacral angle and the way the facets are oriented there. This combination makes pars defects at this level particularly likely to shift forward, especially in adolescents who engage in repetitive hyperextension activities. While slips can occur at other levels, they are far less common because those segments experience less shear stress and different facet mechanics.

The level most commonly involved is the L5 level at the L5–S1 junction. Isthmic spondylolisthesis happens when a defect in the pars interarticularis allows forward slipping of the vertebra. The L5–S1 junction bears the greatest anterior shear forces because of the lumbosacral angle and the way the facets are oriented there. This combination makes pars defects at this level particularly likely to shift forward, especially in adolescents who engage in repetitive hyperextension activities. While slips can occur at other levels, they are far less common because those segments experience less shear stress and different facet mechanics.

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