Evaluation and surgical treatment of high-grade isthmic dysplastic spondylolisthesis.

In children and young adults who seek medical treatment for high-grade isthmic dysplastic spondylolisthesis, common clinical symptoms are referable to the lumbosacral spine and/or the lower extremities. Pain in the lumbosacral spine may be secondary to altered lumbosacral alignment and biomechanics. It also may be caused by malalignment of the entire spinal-pelvic axis as a result of anterior sagittal imbalance. Lower extremity radiculopathies involving the L5 nerve root(s) may be present, and in severe forms of spondylolisthesis crisis, marked entrapment of the cauda equina at L5-S1 may occur. High-grade isthmic dysplastic spondylolisthesis are treated surgically and should include appropriate central and foraminal decompressions at the L5-S1 level, followed by lumbosacral fusion. Partial reduction aiming at improving the slip angle (lumbosacral kyphosis) is more beneficial and provides less risk to the L5 nerve roots than complete reduction of the translational component of the slip. Solid anterior and posterior spinal fusion at L5-S1 appears to provide the best long-term results.