Age / Sex : 63 / M

Chief complaint : Voiding difficulty, left posterior thigh, calf, and heel pain


What is your diagnosis?

Two weeks later, you can see the final diagonosis with a brief discussion of this case (Please submit only one answer).


Courtesy : 김현수 (Hyun Su Kim), 삼성서울병원 (Samsung medical center)

Dural ectasia in ankylosing spondylitis

Discussion

Findings:

Bamboo spine with ankylosis of facet joints and sacroiliac joints.

Dural ectasia with arachnoidal diverticula formation.

Adhesion of nerve roots within the diverticula

Bone erosions at the anterior aspect of vertebra posterior elements

 Differential Diagnosis:

Meningocele, Arachnoid cyst

Diagnosis:  

Dural ectasia in ankylosing spondylitis

Discussion:

Dural ectasia:

- Enlarged spinal dural sac usually involving the lumbosacral regions where the cerebrospinal fluid pressure is greatest

- Marfan syndrome, neurofibromatosis Type I, Ehlers–Danlos syndrome and long-standing ankylosing spondylitis

Dural ectasia in ankylosing spondylitis (AS):

- In long-standing AS, the inflammatory process may extend from the paraspinous ligaments to the dura mater, resulting in adhesion of the dura mater to the surrounding structures that reduce the compliance and elasticity of the lower dural sac and its ability to dampen the fluctuations in CSF pressure

- Exact prevalence of dural ectasia in AS is still unknown

- Dilated dural sac with diverticula formation, adhesion of nerve roots within the diverticula can be seen

- “Empty dural sac” sign can be manifested by adhesion of all the nerve roots

- Bone erosion predominantly involves the posterior elements rather than the posterior aspect of vertebral bodies seen in the other conditions

- Efficacy of medical and surgical treatments are still controversial

References:

 CC Liu, YC Lin, CP Lo et al. Cauda equina syndrome and dural ectasia: rare manifestations in chronic ankylosing spondylitis. Br J Radiol. Jun 2011; 84(1002): e123–e125.

S Ha, B Son. Cauda Equina Syndrome Associated with Dural Ectasia in Chronic Anlylosing Spondylitis. J Korean Neurosurg Soc 56 (6) : 517-520, 2014

R Abello, M Rovira, MP Sanz, A Capdevila et al. MRI and CT of ankylosing spondylitis with vertebral scalloping. Neuroradiology 1988 30:272-275.