Dural Ectasia in the Marfan Spine: Symptoms and Treatment**

Nicholas U. Ahn, MD;
Paul D. Sponseller, MD;
Uri M. Ahn, MD;
L. Nallamshetty, BS;
Peter Rose, BS;
J. Buchowski, MS;
Mesfin Lemma, MD;
Elizabeth Garrett, PhD
Johns Hopkins Hospital Department of Pediatric Orthopaedics, Baltimore, MD, USA

INTRODUCTION:
Dural ectasia (DE) is a ballooning of the dural sac seen in the caudal vertebrae in Marfan syndrome. DE causes severe bony erosions of the lumbosacral spine in these patients. In our review of the literature which included 63 cases, DE was associated with back pain in 32% and neurologic deficits in 17%. However, no well–controlled study exists to determine whether DE is associated with back pain or neurologic deficits in Marfan patients. There is currently no known treatment for DE in symptomatic Marfan patients. All case reports in the literature have described this disease and its symptoms, but have not mentioned a means of treating DE.

MATERIALS AND METHODS:
32 volunteers aged 30–50 with Marfan syndrome were enrolled into age and sex matched pairs with significant back pain (group I) and without back pain (group II). Questionnaire, physical exam, and MRI of the lumbosacral spine were obtained. Dural volume was calculated from the MR data using specially designed software. Patients with symptomatic DE were divided into two groups of seven patients each. The treatment group was given Diamox (acetazolamide) and the control group was not treated. Follow up questionnaire was used to assess improvement after drug therapy. Minimum follow up was 2 years from initiation of this study.

RESULTS:
DE was present in 76% of the patients in group I and 41 % of the patients in group II. The proportion of patients with DE was significantly higher in group I (p=0.03). Furthermore, mean dural volume was significantly higher in group I (p=0.04) and a significant correlation existed between dural volume and Oswestry score (p=0.05). Fourteen patients had symptomatic DE; 7 were in the treatment group. The proportion of patients who improved > 20 Oswestry points in the treatment group was significantly higher than that in the control group (p=0.03).

CONCLUSIONS:
The presence and size of DE is associated with back pain in the Marfan syndrome. However. a high prevalence of dural ectasia (41 %) exists even in Marfan patients without back pain. The mere presence of dural ectasia therefore does not necessarily mean the patient will be symptomatic even though the two are associated. Diamox (acetazolamide) appears to be useful in treating Marfan patients with symptomatic DE. Two year follow up has shown significant functional improvements, and further trials are currently under way for this difficult problem.

** The FDA has not cleared a drug and/or medical device for the use described in this presentation. (i.e., the drug or medical device is being discussed in an “off–label" use).