Clinical Outcomes of Patients with Delayed Diagnosis of Spinal Dural Arteriovenous Fistulas.
OBJECTIVE
Spinal dural arteriovenous fistulas are commonly missed on imaging or misdiagnosed as inflammatory or neoplastic processes. We reviewed a consecutive series of spinal dural arteriovenous fistulas referred to our institution that were missed or misdiagnosed on initial imaging and studied the clinical consequences of missing or misdiagnosing the lesion.


METHODS
We reviewed spinal dural arteriovenous fistulas diagnosed at our institution between January 1, 2000, and November 1, 2014. A lesion was defined as "misdiagnosed" if initial MR imaging or CT myelography demonstrated characteristic imaging features of spinal dural arteriovenous fistula but the patient was clinically or radiologically misdiagnosed. Outcomes included length of delay of diagnosis, increased disability (increase in mRS or Aminoff motor disability of ≥1 point) between initial imaging evaluation and diagnosis date, and posttreatment disability.


RESULTS
Fifty-three consecutive spinal dural arteriovenous fistulas that were initially misdiagnosed despite having characteristic imaging findings on MR imaging or CT myelography were included in our study. Eight patients (18.9%) underwent spinal angiography before referral, which was interpreted as having negative findings but was either incomplete (6 cases) or retrospectively demonstrated the spinal dural arteriovenous fistulas (2 cases). The median time of delayed diagnosis was 6 months (interquartile range, 2-14 months). Fifty-one patients (96.2%) had increased disability between the initial study, which demonstrated features of a spinal dural arteriovenous fistula, and diagnosis. Thirty-two patients (60.4%) developed a new requirement for a walker or wheelchair. Following treatment, 21 patients (41.2%) had an improvement of 1 point on the mRS or Aminoff motor disability scale.


CONCLUSIONS
Delayed diagnosis of spinal dural arteriovenous fistula with characteristic imaging features results in high rates of additional disability that are often irreversible despite surgical or endovascular treatment of the fistula.
From Departments of Radiology (W.B., J.M.M.) Brinjikji.waleed@mayo.edu.
W
http://orcid.org/0000-0001-5271-5524
W
Brinjikji
Neurology (D.M.N., A.A.R.).
D M
http://orcid.org/0000-0002-2676-5779
DM
Nasr
From Departments of Radiology (W.B., J.M.M.).
J M
http://orcid.org/0000-0001-5035-3910
JM
Morris
Neurology (D.M.N., A.A.R.).
A A
http://orcid.org/0000-0001-8359-2838
AA
Rabinstein
Neurosurgery (G.L.) Center for Science of Healthcare Delivery (G.L.), Mayo Clinic, Rochester, Minnesota.
G
http://orcid.org/0000-0003-1479-465X
G
Lanzino
D000328:Adult; D000368:Aged; D020785:Central Nervous System Vascular Malformations / Q000150:complications* / Q000175:diagnosis*; D057210:Delayed Diagnosis; D003951:Diagnostic Errors; D004185:Disability Evaluation; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D012189:Retrospective Studies