Clinical outcomes following corticosteroid administration in patients with delayed diagnosis of spinal arteriovenous fistulas

Background and purpose: There have been several previously reported cases of acute progression of myelopathic symptoms in patients with spinal arteriovenous fistula (SAVF) treated with intravenous methylprednisolone. This usually occurs during or immediately following steroid administration. We examined a small case series of patients with SAVF treated with epidural, oral, or intravenous steroids to determine the association between steroid administration and clinical outcomes in these patients. Methods: Following Institutional Review Board approval, we conducted a retrospective review of patients with angiographically-confirmed SAVF who received intravenous, oral, or epidural corticosteroids for treatment of their symptoms. We studied patientreported motor and sensory function following steroid administration using both the modified Rankin Scale and the Aminoff Motor Disability Scale. Results: Twenty-one patients with SAVF were included in this study. Thirteen patients (61.9%) had intravenous methylprednisolone administered, four patients (19.0%) had epidural steroid injections, and six patients (28.6%) had oral prednisone. Among patients who received intravenous methylprednisolone, seven (53.8%) reported acute worsening of symptoms during or immediately following steroid administration. Among the patients receiving epidural steroids, none reported worsening and one patient reported short-term relief. Among the patients receiving oral steroids, one reported acute worsening of symptoms. Worsened deficits did not consistently resolve after steroid discontinuation. Conclusions: Our study suggests that intravenous methylprednisolone can cause immediate worsening of motor and sensory symptoms when administered to patients with SAVF. Steroid administration should be avoided in patients with a myelopathy secondary to an untreated SAVF because neurological worsening may not be fully reversible.