Dural ectasia

Last revised by Subhan Iqbal on 31 Jan 2024

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.

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 meningoceles which may present as an abdominal mass.

Dural ectasia describes widening of the dural sac or spinal nerve root sleeves, usually associated with bony erosions of the posterior vertebral body 4. One study suggests that the anteroposterior diameter of the thecal sac at the S1 level should be greater than that of the thecal sac at the L4 level in order to describe dural ectasia 4.

Posterior vertebral scalloping on a lateral radiograph may be an indirect indicator 1,2,4. 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 anteroposterior diameter of the dural sac, usually in the lumbar region 4.

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