Figure 5.

The axial non-contrast lumbar CT scan demonstrates marked congenital stenosis accompanied by superior facet hypertrophy. Note that air (hypodense) within the facet joints is indicative of instability. With such severe spinal stenosis, epidural steroid injections would likely fail or result in dural fistulas as there is essentially no epidural compartment. Similarly, if this patient had a synovial cyst, there would have been virtually no space available for “cyst aspiration”