Surgical and Clinical Outcomes After Microsurgical Clip Occlusion of Spinal Epidural Arteriovenous Fistulas

Introduction: Spinal epidural arteriovenous fistulas (ED-AVFs) are a rare but clinically distinct subset of spinal vascular malformations. The aim of this study was to report surgical and clinical outcomes for a large contemporary series of patients with spinal ED-AVFs treated with microsurgical clip occlusion.

Methods: A bi-institutional, single-surgeon neurovascular database was queried for patients with spinal ED-AVFs between 2007 and 2022. Clinical data capture included demographics, radiographic, surgical, and clinical (modified Rankin Scale [mRS], modified McCormick Scale, Aminoff-Logue Scale [ALS]) outcomes.

Results: Fifteen patients were identified. The mean (SD) age was 62 (18) years and 67% were male. Lesions were located in the cervical (27%, n=4), thoracic (20%, n=3), and lumbar (53%, n=8) spine. Patients presented with pain (53%, n=8), paresis (93%, n=14), paresthesias (47%, n=7), bowel and bladder dysfunction (20%, n=3), and prior hemorrhage (20%, n=3). Nine (60%) lesions were previously embolized. Treatment included intradural occlusion in 8 (53%) and extradural occlusion in 7 (47%). The mean (SD) follow-up time was 13 (20) months. Patients reported improved (mRS, 69% [9/13]; McCormick, 15% [2/13]; ALS, 77% [10/13]) or unchanged (mRS, 31% [4/13]; McCormick, 85% [11/13]; ALS, 23% [3/13]) outcomes postoperatively. At follow-up, patients reported improved (mRS, 85% [11/13]; McCormick, 69% [9/13]; ALS, 85% [11/13]) or unchanged (mRS, 31% [4/13]; McCormick, 31% [4/13]; ALS, 15% [2/13]) outcomes. All procedures took place without complications. Two (13%) patients underwent repeat surgery for clip occlusion of residual fistulous shunting. Intraoperative indocyanine green videoangiography confirmed complete occlusion of ED-AVF with a 92% negative predictive value (11/12), as was confirmed by postoperative digital subtraction angiography for all cases.

Conclusion : Spinal ED-AVFs may present with significant symptoms. Surgical and clinical outcomes after microsurgical clip occlusion are favorable, with either intradural or extradural technique, often resulting in immediate symptom relief postoperatively.