Radiographic analysis of the listhesis associated with lumbar isthmic spondylolysis.

BACKGROUND

In cases of spondylolysis, hypoplasia of L5 mimicking spondylolisthesis has been described, mainly based on MRI; however, the treatment implications have not been analyzed specifically.

OBJECTIVE

Assess the impact of hypoplasia of the L5 vertebral body in the constitution of the spondylolisthesis associated with isthmic spondylolysis.

MATERIAL AND

METHODS

A retrospective radiographic study in the standing position was performed with 104 patients with L5 isthmic spondylolysis and 24 control subjects.

RESULTS

Measurements of vertebral endplate length showed that the standard apparent posterior listhesis (APL) is made up of true listhesis (TL) and false listhesis (FL). FL is induced by hypoplasia of the L5 vertebral body relative to the S1 endplate. TL results from disk failure and leads to anterior listhesis (AL), which alters the balance of spinal curvatures.

CONCLUSIONS

By integrating the potential for false listhesis into the classification systems for spondylolisthesis, we can adapt the treatment algorithms.

TYPE OF STUDY: Retrospective radiography study.

LEVEL OF EVIDENCE: IV Retrospective review of cases.