Bilateral mirror image lumbar spinal dural arterial venous fistula: a rare case and systematic review of the literature

Background: Spinal dural arteriovenous fistulas (SDAVF) are rare with an incidence of 5-10/million annually. They can be difficult to diagnose causing a delay in treatment with significant morbidity. We describe the first case in the literature of a symptomatic mirror lumbar SDAVF which may go unnoticed due to its unique vascular anatomy.

Case description: A 78-year-old gentleman presented with a progressive deterioration in his walking distance and urinary retention. An initial MRI scan of the whole spine did not show features suggestive of an underlying vascular malformation. During further investigations of neurological causes, the patient continued to have progressive symptoms over a 10-month period resulting in a repeat MRI scan. This showed a new finding of cord oedema without abnormal flow voids. He went on to have vascular imaging which demonstrated a mirror L3 SDAVF and underwent subsequent surgical management. At follow up there was a significant improvement in symptoms.

Conclusions: Completing a systematic review of the literature we find that the mirror lumbar SDAVF in our patient presented in a more aggressive manner with symptoms progressing faster than in single or multi-level SDAVF. Our case demonstrates how this unique vascular anatomy may result in a diagnostic challenge, behaving in an occult way where typical findings are not seen on initial MRI scanning. We provide an argument for early vascular imaging which can result in the treatment of these lesions in a timely manner.