Effects of corticosteroid pretreatment in patients with spinal dural arteriovenous fistula

Background and Purpose: Spinal arteriovenous fistulas, especially dural types (SdAVFs), are often misdiagnosed as inflammatory myelopathies, leading to inadvertent corticosteroid therapy. This study systematically evaluated the clinical consequences of steroid pretreatment in SdAVF and its underlying pathophysiological mechanisms. Methods: A PRISMA-compliant systematic review and pooled analysis were conducted across PubMed, Scopus, and Embase on October 10th, 2025. Quantitative data on patients receiving corticosteroids before SdAVF diagnosis were extracted, including demographic, clinical, radiologic, and outcome measures. Comparative and paired analyses (χ², Kruskal-Wallis and Wilcoxon tests) assessed associations between steroid exposure, fistula location, and modified Aminoff–Logue Scale (mALS) outcomes. Results: Seventy-one studies, including 161 patients from case series and 86 from pooled case reports, were included. Across the pooled cohort of case reports, 81.4% of steroid-treated patients experienced neurological worsening. In case series, worsening remained frequent, occurring in 54.7% of patients. Paired analysis confirmed significant deterioration in gait, urinary, and fecal mALS domains after steroid administration (p < 0.01, p < 0.001, p = 0.006). Conclusions: Steroid therapy in SdAVF has been associated with neurological deterioration, due to possibly aggravating venous hypertension and precipitating irreversible myelopathy. Clinicians should avoid empiric corticosteroids in unexplained progressive myelopathy and pursue early vascular imaging to exclude SdAVF.