Dural ectasia

Dural ectasia refers to ballooning or widening of the dural sac which can result in posterior vertebral scalloping and is associated with herniation of nerve root sleeves.

Clinical presentation

Patients with dural ectasia may present with low back pain or radicular pain in the buttocks or legs. Pain may be accompanied by leg weakness or urinary incontinence. Other associations include spondylolisthesis, scoliosis, vertebral erosions and vertebral fractures. There is also an increased incidence of anterior sacral meningocoeles which may present as an abdominal mass.


Radiographic features

Dural ectasia is dilation of the dural sac. Anteroposterior diameter of the thecal sac at the S1 level greater than that of the thecal sac at the L4 level ref required.

Plain radiograph

Posterior vertebral scalloping may be an indirect indicator 1-2. However, this is not specific, as it is seen in a significant percentage of the normal population and is also associated with several other conditions.


Increase in the AP diameter of the dural sac, usually in the lumbar region.

Differential diagnosis

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