Dynamic degenerative lumbar spondylolisthesis: diagnosis with axial loaded magnetic resonance imaging.

Study Design: Retrospective review of case notes and imaging.

Objective: To show the advantage of axial loaded magnetic resonance imaging (MRI) for identification of dynamic degenerative spondylolisthesis as a suspected cause of spinal claudication.

Summary Of Background Data: Degenerative spondylolisthesis typically occurs at L4/L5 and is usually evident on plain radiography. However, dynamic degenerative spondylolisthesis may become evident on erect radiographs when not shown on supine radiographs or MRI.

Methods: The case notes and imaging (radiography, conventional MRI, and axial loaded MRI) in 2 patients with symptoms of spinal claudication were reviewed.

Results: A 44-year-old female presented with a 3-year history of intermittent low back pain and right leg numbness after a fall. A 52-year-old female presented with a 4-year history of low back pain, bilateral leg weakness, and right leg numbness. In both cases, conventional MRI studies showed mild-to-moderate degenerative disc disease only with no evidence of abnormal spinal alignment or nerve root compression. Axial loaded MRI clearly showed the development of a degenerative spondylolisthesis with central canal stenosis and facet ganglion formation in 1 case.

Conclusions: Axial loaded MRI identified occult dynamic degenerative spondylolisthesis, which correlated with the clinical picture but was not shown on initial conventional MRI or plain radiography.