Data Supplement

Two tables; Word document.

Files in this Data Supplement:

• E1 - Table (E) T-1: Clinical features (Abbreviations-y: years, the time in years indicates duration of symptoms and not age at symptom onset unless indicated otherwise, F: female, M: male, L: left, R: right, MVA: motor vehicle accident, LE: lower extremity, UE: upper extremity); Table (E) T-2: Findings on MRI, angiogram, and myelogram. (Abbreviations: NA: not available: +: present, -: absent, R: right, L: left, SDH: subdural hematoma, AV: arteriovenous, * indicates those patients who had surgical intervention); Word document.