Spinal Dural Arteriovenous Fistula Presenting as a Recurrent Nucleus Pulposus Herniation: A Case Report and Literature Review.

CASE: Of the many potential causes of nerve compression that lead to radiculopathy, vascular etiologies remain among the most infrequent, with an estimated prevalence of only five to ten per million cases of radiculopathy. In this case report, we outline the clinical presentation, imaging, intraoperative findings, and pathologic findings for a fifty-four-year old patient with an intradural, extramedullary form of a spinal dural arteriovenous fistula at the L1-L2 level who presented only with axial back pain and radiculopathy. The radiologist and surgeon initially diagnosed the patient with a herniated nucleus pulposus. However, the intraoperative findings and angiogram were suggestive of an arteriovenous fistula. Methods to identify this rare entity are described for the orthopaedic spine community.

CONCLUSION

The potential for a missed diagnosis is particularly important as many partial discectomy procedures are performed at small surgical centers with limited blood products available and no vascular surgeon on staff. For patients with preoperative magnetic resonance imaging (MRI) that is suggestive of vascular malformations (T2 hyperintensity in the lower spinal cord and conus medullaris), we recommend that MR angiography be performed as a secondary diagnostic evaluation. MR angiography has a 95% positive predictive value for specifically diagnosing an arteriovenous fistula.