Degeneration (Lumbar)

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Clinical History:
A 76 year old man with advanced degenerative spine disease

Diagnosis:
Lumbar spinal stenosis

MR Technique:
4 mm sagittal pre-contrast FSE (3 echoes) T1- and FSE (15 echoes) T2-weighted images are presented, acquired at 1.5 T on a Siemens Espree MR system. Sequence parameters were TR/TE = 665/9.8 and 3130/94 respectively. Scan times were 3:35 and 3:34 min:sec.

Imaging Findings:
There is a grade 1 (<25%) anterolisthesis at L3-L4 and a mild retrolisthesis at L5-S1. There is disc desiccation at all lumbar levels with moderate loss of disc space height at L5-S1. There are mild disc-osteophyte complexes at all lumbar levels. At L3-L4, there is severe central canal stenosis due to a combination of the anterolisthesis, a mild disc osteophyte complex, moderate bilateral facet osteoarthritis, and ligamentum flavum hypertrophy. The latter two contributory factors were identified on axial images (not shown). There is also mild central canal stenosis at L4-L5.

Although not provided in this case presentation, axial images are critical (in addition to sagittal images) for the assessment of central canal stenosis. With degenerative stenosis in the lumbar spine, typically a disk osteophyte complex, facet osteoarthritis, and ligamentum flavum hypertrophy all contribute. In this patient, there is the additional factor of a grade 1 anterolisthesis.

When presented with an anterolisthesis, an important analysis is to decide whether there is an accompanying bilateral pars defect (spondylolysis), in addition to the spondylolisthesis. If the canal AP dimension is preserved, a bilateral pars defect should be present and looked for, whereas (as in this case) where there is canal stenosis, the pars should be intact.