Spinal Epidural Fistulas–A Separate Entity to Dural Fistulas with Different Angioarchitecture and Treatment Approach

• Published in: World neurosurgery Vol. 149; pp. e600 - e611
• Main Authors: Shetty, Gurucharan S., Singh, Vivek, Prasad, Surya Nandan, Phadke, Rajendra V., Neyaz, Zafar, Udiya, Alok, Behari, Sanjay
• Format: Journal Article
• Language: English
• Published: United States Elsevier Inc 01-05-2021
• Subjects: Dural; Embolization; Endovascular; Epidural; Spinal; Spinal; Epidural; AVF; MRI; Endovascular; Dural; Embolization; SEAVF
• ISSN: 1878-8750; 1878-8769
• DOI: 10.1016/j.wneu.2021.01.126

Spinal epidural arteriovenous fistulas (SEAVFs) are the rarest variety of spinal vascular malformation and are often misdiagnosed as type 1 spinal dural fistula. This retrospective study highlights the salient anatomic differentiating points of these entities and also highlights the importance of a planned endovascular treatment approach using different routes of access. Efficacy of the endovascular treatment at 3 months follow-up was also studied.
We retrospectively reviewed 11 treated patients with SEAVF. Existence of epidural arteriovenous fistula in all these patients was confirmed by spinal angiography. The Aminoff-Logue Scale score was assigned both before and after the procedure. The statistical results were expressed as percentages, and the preprocedure scale was compared with the postprocedure scale at 3 months by using a nonparametric Wilcoxon signed-rank test.
The patients ranged in age from 7 to 53 years, with male predominance. Paraparesis was the commonest symptom, and 1 patient had congestive cardiac failure caused by a large fistula. Location was mostly dorsolumbar with intradural venous reflux into the perimedullary venous system (Castilla type A) noted in 3/11(27%) patients, and the remaining 73% patients had Castilla type B1 with an enlarged epidural venous sac. Therapeutic embolization was performed from arterial, venous, or combined routes. The 3-month postprocedure clinical assessment showed statistically significant (P < 0.004) improvement in the Aminoff-Logue Scale score.
The differentiating points between SEAVF compared with type 1 spinal dural fistula are emphasized. The study also highlights the importance of a good angiographic assessment to best access the fistula by arterial, venous, percutaneous, or combined routes. Endovascular treatment resulted in statistically significant clinical improvement at 3 months follow-up.